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Re: [softrock40] Re: Troubleshooting Softrock lite RX

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  • Tony Parks
    Hi Norman, How do the signals look on C11 and C13 with reference to circuit ground when you have an RF input to the antenna terminals? 73, Tony KB9YIG ...
    Message 1 of 20 , Dec 1, 2008
    • 0 Attachment
      Hi Norman,
       
      How do the signals look on C11 and C13 with reference to circuit ground when you have an RF input to the antenna terminals?
       
      73,
      Tony KB9YIG
      ----- Original Message -----
      Sent: Monday, December 01, 2008 7:32 AM
      Subject: [softrock40] Re: Troubleshooting Softrock lite RX

      Dear Tony

      OK I'm really lost now.

      Carefully checked all component values and soldering of T1 leads -
      all seems OK. Checked all leads and for solder bridges with high
      magnification and all seems OK.

      With no power and no signal there is continuity between the two ends
      of T1. There is 20 ohms between pins 11 and 12 of U4 and also
      between pins 3 and 6.

      There is 774 ohms between CT of T1 and pin 8 of U5, and essentially
      zero ohms between CT of T1 and pins 3 and 5 of U5.

      With no power and 1V p/p at 7.1MHz on the antenna there are
      symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6 on U4 -
      all suggests T1 is OK.

      With power on the board and no signal, there is 5.4V p/p at 7.15 MHZ
      on the two test points on the board - square wave and 90 phase
      shifted and these signals are also on pins 2 and 14 of U4.

      With power on and around 50 mV ont he antenna at 7.15 Mhz there is
      about 1V of AF on the Q line and essentially nothing on the I line.

      When I measured the voltahes around U%, all were OK but the "normal"
      values (both 2.47V) both went to 4.93 when a 2.6K resistor was used
      to bridge the inputs - Robbie's program predicts 3.41V.

      Is it possible that one channel of U5 just isn't working? or is
      there some other possible fault?

      Any ides gratefully received

      TIA

      Norman

      --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@...> wrote:
      >
      > Hi Norman,
      >
      > Please check the soldering around T1 and make sure the resistor
      values are according to the schematic.
      >
      > 73,
      > Tony KB9YIG
      > ----- Original Message -----
      > From: norman.billingham
      > To: softrock40@yahoogro ups.com
      > Sent: Sunday, November 30, 2008 12:53 PM
      > Subject: [softrock40] Troubleshooting Softrock lite RX
      >
      >
      > Dear all
      >
      > Hopefully someone can offer words of help to a non-expert.
      >
      > I just finished my second softrock, using a V6.0 kit I've had for
      a
      > while.
      >
      > When I inject about 50mV of signal into the antenna at about
      16kHz
      > off centre, I get a beautiful sine wave at both I and Q and 90o
      phase
      > shift but the p/p voltage on Q is about 3.5 V and on I is only
      around
      > 50mV.
      >
      > I followed the detailed instructions and tests on WB5RVZ's great
      > pages and all checked out OK except for:
      >
      > The op-amps. All voltages were OK but the "normal" values (both
      > 2.47V) both went to 4.93 when a 2.6K resistor was used to bridge
      the
      > inputs - Robbie's program predicts 3.41V
      >
      > I measure 500mV at pins 1 and 15 on the mixer where Robbie's
      values
      > are 45 mV - looking at the circuit, these pins are both on an
      1/11K
      > potential divider from the 5V rail and 500mV is the calculated
      value.
      >
      > I've checked all the component values and soldering around the op
      > amps and can't find a problem.
      >
      > Anyone any good ideas please?
      >
      > Thanks in advance
      >
      > Norman (M0EBI)
      >

    • norman.billingham
      Hi Tony Thanks for coming back so fast This is a 6.0 board so I assume you mean C12 and C13, the two 0.047 uF decouplers? With my scope AC coupled and on its
      Message 2 of 20 , Dec 1, 2008
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        Hi Tony

        Thanks for coming back so fast

        This is a 6.0 board so I assume you mean C12 and C13, the two 0.047
        uF decouplers? With my scope AC coupled and on its best sensitvity,
        and 50mV of RF on the input all I can see there (or at pins 7 and 9
        of U4) is about 20 mV of local oscillator frequency. Likewise at
        pins 2 and 6 of U5.

        Pin 1 of U5 is producing nothing and pin 7 has a nice strong Q signal
        at just the right audio frequency.

        73

        Norman


        --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
        >
        > Hi Norman,
        >
        > How do the signals look on C11 and C13 with reference to circuit
        ground when you have an RF input to the antenna terminals?
        >
        > 73,
        > Tony KB9YIG
        > ----- Original Message -----
        > From: norman.billingham
        > To: softrock40@yahoogroups.com
        > Sent: Monday, December 01, 2008 7:32 AM
        > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
        >
        >
        > Dear Tony
        >
        > OK I'm really lost now.
        >
        > Carefully checked all component values and soldering of T1 leads -

        > all seems OK. Checked all leads and for solder bridges with high
        > magnification and all seems OK.
        >
        > With no power and no signal there is continuity between the two
        ends
        > of T1. There is 20 ohms between pins 11 and 12 of U4 and also
        > between pins 3 and 6.
        >
        > There is 774 ohms between CT of T1 and pin 8 of U5, and
        essentially
        > zero ohms between CT of T1 and pins 3 and 5 of U5.
        >
        > With no power and 1V p/p at 7.1MHz on the antenna there are
        > symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6 on
        U4 -
        > all suggests T1 is OK.
        >
        > With power on the board and no signal, there is 5.4V p/p at 7.15
        MHZ
        > on the two test points on the board - square wave and 90 phase
        > shifted and these signals are also on pins 2 and 14 of U4.
        >
        > With power on and around 50 mV ont he antenna at 7.15 Mhz there
        is
        > about 1V of AF on the Q line and essentially nothing on the I
        line.
        >
        > When I measured the voltahes around U%, all were OK but
        the "normal"
        > values (both 2.47V) both went to 4.93 when a 2.6K resistor was
        used
        > to bridge the inputs - Robbie's program predicts 3.41V.
        >
        > Is it possible that one channel of U5 just isn't working? or is
        > there some other possible fault?
        >
        > Any ides gratefully received
        >
        > TIA
        >
        > Norman
        >
        > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
        > >
        > > Hi Norman,
        > >
        > > Please check the soldering around T1 and make sure the resistor
        > values are according to the schematic.
        > >
        > > 73,
        > > Tony KB9YIG
        > > ----- Original Message -----
        > > From: norman.billingham
        > > To: softrock40@yahoogroups.com
        > > Sent: Sunday, November 30, 2008 12:53 PM
        > > Subject: [softrock40] Troubleshooting Softrock lite RX
        > >
        > >
        > > Dear all
        > >
        > > Hopefully someone can offer words of help to a non-expert.
        > >
        > > I just finished my second softrock, using a V6.0 kit I've had
        for
        > a
        > > while.
        > >
        > > When I inject about 50mV of signal into the antenna at about
        > 16kHz
        > > off centre, I get a beautiful sine wave at both I and Q and 90o
        > phase
        > > shift but the p/p voltage on Q is about 3.5 V and on I is only
        > around
        > > 50mV.
        > >
        > > I followed the detailed instructions and tests on WB5RVZ's
        great
        > > pages and all checked out OK except for:
        > >
        > > The op-amps. All voltages were OK but the "normal" values (both
        > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
        bridge
        > the
        > > inputs - Robbie's program predicts 3.41V
        > >
        > > I measure 500mV at pins 1 and 15 on the mixer where Robbie's
        > values
        > > are 45 mV - looking at the circuit, these pins are both on an
        > 1/11K
        > > potential divider from the 5V rail and 500mV is the calculated
        > value.
        > >
        > > I've checked all the component values and soldering around the
        op
        > > amps and can't find a problem.
        > >
        > > Anyone any good ideas please?
        > >
        > > Thanks in advance
        > >
        > > Norman (M0EBI)
        > >
        >
      • Tony Parks
        Hi Norman, Please repeat the DC gain test for the dual op-amp. A 10k resistor to ground at pin 2 or pin 6 should result in a voltage change of 1.25 volts at
        Message 3 of 20 , Dec 1, 2008
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          Hi Norman,
           
          Please repeat the DC gain test for the dual op-amp.  A 10k resistor to ground at pin 2 or pin 6 should result in a voltage change of 1.25 volts at pin 1 or pin 7 respectively.
           
          73,
          Tony KB9YIG 
          ----- Original Message -----
          Sent: Monday, December 01, 2008 10:20 AM
          Subject: [softrock40] Re: Troubleshooting Softrock lite RX

          Hi Tony

          Thanks for coming back so fast

          This is a 6.0 board so I assume you mean C12 and C13, the two 0.047
          uF decouplers? With my scope AC coupled and on its best sensitvity,
          and 50mV of RF on the input all I can see there (or at pins 7 and 9
          of U4) is about 20 mV of local oscillator frequency. Likewise at
          pins 2 and 6 of U5.

          Pin 1 of U5 is producing nothing and pin 7 has a nice strong Q signal
          at just the right audio frequency.

          73

          Norman

          --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@...> wrote:
          >
          > Hi Norman,
          >
          > How do the signals look on C11 and C13 with reference to circuit
          ground when you have an RF input to the antenna terminals?
          >
          > 73,
          > Tony KB9YIG
          > ----- Original Message -----
          > From: norman.billingham
          > To: softrock40@yahoogro ups.com
          > Sent: Monday, December 01, 2008 7:32 AM
          > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
          >
          >
          > Dear Tony
          >
          > OK I'm really lost now.
          >
          > Carefully checked all component values and soldering of T1 leads -

          > all seems OK. Checked all leads and for solder bridges with high
          > magnification and all seems OK.
          >
          > With no power and no signal there is continuity between the two
          ends
          > of T1. There is 20 ohms between pins 11 and 12 of U4 and also
          > between pins 3 and 6.
          >
          > There is 774 ohms between CT of T1 and pin 8 of U5, and
          essentially
          > zero ohms between CT of T1 and pins 3 and 5 of U5.
          >
          > With no power and 1V p/p at 7.1MHz on the antenna there are
          > symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6 on
          U4 -
          > all suggests T1 is OK.
          >
          > With power on the board and no signal, there is 5.4V p/p at 7.15
          MHZ
          > on the two test points on the board - square wave and 90 phase
          > shifted and these signals are also on pins 2 and 14 of U4.
          >
          > With power on and around 50 mV ont he antenna at 7.15 Mhz there
          is
          > about 1V of AF on the Q line and essentially nothing on the I
          line.
          >
          > When I measured the voltahes around U%, all were OK but
          the "normal"
          > values (both 2.47V) both went to 4.93 when a 2.6K resistor was
          used
          > to bridge the inputs - Robbie's program predicts 3.41V.
          >
          > Is it possible that one channel of U5 just isn't working? or is
          > there some other possible fault?
          >
          > Any ides gratefully received
          >
          > TIA
          >
          > Norman
          >
          > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
          > >
          > > Hi Norman,
          > >
          > > Please check the soldering around T1 and make sure the resistor
          > values are according to the schematic.
          > >
          > > 73,
          > > Tony KB9YIG
          > > ----- Original Message -----
          > > From: norman.billingham
          > > To: softrock40@yahoogro ups.com
          > > Sent: Sunday, November 30, 2008 12:53 PM
          > > Subject: [softrock40] Troubleshooting Softrock lite RX
          > >
          > >
          > > Dear all
          > >
          > > Hopefully someone can offer words of help to a non-expert.
          > >
          > > I just finished my second softrock, using a V6.0 kit I've had
          for
          > a
          > > while.
          > >
          > > When I inject about 50mV of signal into the antenna at about
          > 16kHz
          > > off centre, I get a beautiful sine wave at both I and Q and 90o
          > phase
          > > shift but the p/p voltage on Q is about 3.5 V and on I is only
          > around
          > > 50mV.
          > >
          > > I followed the detailed instructions and tests on WB5RVZ's
          great
          > > pages and all checked out OK except for:
          > >
          > > The op-amps. All voltages were OK but the "normal" values (both
          > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
          bridge
          > the
          > > inputs - Robbie's program predicts 3.41V
          > >
          > > I measure 500mV at pins 1 and 15 on the mixer where Robbie's
          > values
          > > are 45 mV - looking at the circuit, these pins are both on an
          > 1/11K
          > > potential divider from the 5V rail and 500mV is the calculated
          > value.
          > >
          > > I've checked all the component values and soldering around the
          op
          > > amps and can't find a problem.
          > >
          > > Anyone any good ideas please?
          > >
          > > Thanks in advance
          > >
          > > Norman (M0EBI)
          > >
          >

        • norman.billingham
          Hi Tony pin 1 goes from 2.49 to 3.73V with 10K at pin 2 pin 7 goes from 2.49 to 3.89 with 10K at pin 6 Norman ... to ground at pin 2 or pin 6 should result in
          Message 4 of 20 , Dec 1, 2008
          • 0 Attachment
            Hi Tony

            pin 1 goes from 2.49 to 3.73V with 10K at pin 2

            pin 7 goes from 2.49 to 3.89 with 10K at pin 6

            Norman



            --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
            >
            > Hi Norman,
            >
            > Please repeat the DC gain test for the dual op-amp. A 10k resistor
            to ground at pin 2 or pin 6 should result in a voltage change of 1.25
            volts at pin 1 or pin 7 respectively.
            >
            > 73,
            > Tony KB9YIG
            > ----- Original Message -----
            > From: norman.billingham
            > To: softrock40@yahoogroups.com
            > Sent: Monday, December 01, 2008 10:20 AM
            > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
            >
            >
            > Hi Tony
            >
            > Thanks for coming back so fast
            >
            > This is a 6.0 board so I assume you mean C12 and C13, the two
            0.047
            > uF decouplers? With my scope AC coupled and on its best
            sensitvity,
            > and 50mV of RF on the input all I can see there (or at pins 7 and
            9
            > of U4) is about 20 mV of local oscillator frequency. Likewise at
            > pins 2 and 6 of U5.
            >
            > Pin 1 of U5 is producing nothing and pin 7 has a nice strong Q
            signal
            > at just the right audio frequency.
            >
            > 73
            >
            > Norman
            >
            > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
            > >
            > > Hi Norman,
            > >
            > > How do the signals look on C11 and C13 with reference to
            circuit
            > ground when you have an RF input to the antenna terminals?
            > >
            > > 73,
            > > Tony KB9YIG
            > > ----- Original Message -----
            > > From: norman.billingham
            > > To: softrock40@yahoogroups.com
            > > Sent: Monday, December 01, 2008 7:32 AM
            > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
            > >
            > >
            > > Dear Tony
            > >
            > > OK I'm really lost now.
            > >
            > > Carefully checked all component values and soldering of T1
            leads -
            >
            > > all seems OK. Checked all leads and for solder bridges with
            high
            > > magnification and all seems OK.
            > >
            > > With no power and no signal there is continuity between the two
            > ends
            > > of T1. There is 20 ohms between pins 11 and 12 of U4 and also
            > > between pins 3 and 6.
            > >
            > > There is 774 ohms between CT of T1 and pin 8 of U5, and
            > essentially
            > > zero ohms between CT of T1 and pins 3 and 5 of U5.
            > >
            > > With no power and 1V p/p at 7.1MHz on the antenna there are
            > > symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6
            on
            > U4 -
            > > all suggests T1 is OK.
            > >
            > > With power on the board and no signal, there is 5.4V p/p at
            7.15
            > MHZ
            > > on the two test points on the board - square wave and 90 phase
            > > shifted and these signals are also on pins 2 and 14 of U4.
            > >
            > > With power on and around 50 mV ont he antenna at 7.15 Mhz there
            > is
            > > about 1V of AF on the Q line and essentially nothing on the I
            > line.
            > >
            > > When I measured the voltahes around U%, all were OK but
            > the "normal"
            > > values (both 2.47V) both went to 4.93 when a 2.6K resistor was
            > used
            > > to bridge the inputs - Robbie's program predicts 3.41V.
            > >
            > > Is it possible that one channel of U5 just isn't working? or is
            > > there some other possible fault?
            > >
            > > Any ides gratefully received
            > >
            > > TIA
            > >
            > > Norman
            > >
            > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
            > > >
            > > > Hi Norman,
            > > >
            > > > Please check the soldering around T1 and make sure the
            resistor
            > > values are according to the schematic.
            > > >
            > > > 73,
            > > > Tony KB9YIG
            > > > ----- Original Message -----
            > > > From: norman.billingham
            > > > To: softrock40@yahoogroups.com
            > > > Sent: Sunday, November 30, 2008 12:53 PM
            > > > Subject: [softrock40] Troubleshooting Softrock lite RX
            > > >
            > > >
            > > > Dear all
            > > >
            > > > Hopefully someone can offer words of help to a non-expert.
            > > >
            > > > I just finished my second softrock, using a V6.0 kit I've had
            > for
            > > a
            > > > while.
            > > >
            > > > When I inject about 50mV of signal into the antenna at about
            > > 16kHz
            > > > off centre, I get a beautiful sine wave at both I and Q and
            90o
            > > phase
            > > > shift but the p/p voltage on Q is about 3.5 V and on I is
            only
            > > around
            > > > 50mV.
            > > >
            > > > I followed the detailed instructions and tests on WB5RVZ's
            > great
            > > > pages and all checked out OK except for:
            > > >
            > > > The op-amps. All voltages were OK but the "normal" values
            (both
            > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
            > bridge
            > > the
            > > > inputs - Robbie's program predicts 3.41V
            > > >
            > > > I measure 500mV at pins 1 and 15 on the mixer where Robbie's
            > > values
            > > > are 45 mV - looking at the circuit, these pins are both on an
            > > 1/11K
            > > > potential divider from the 5V rail and 500mV is the
            calculated
            > > value.
            > > >
            > > > I've checked all the component values and soldering around
            the
            > op
            > > > amps and can't find a problem.
            > > >
            > > > Anyone any good ideas please?
            > > >
            > > > Thanks in advance
            > > >
            > > > Norman (M0EBI)
            > > >
            > >
            >
          • Tony Parks
            Hi Norman, The DC gain of each of op-amp is about right. When you checked for the AC I and Q outputs was it at pins 1 and 7 of the dual op-amp each with
            Message 5 of 20 , Dec 1, 2008
            • 0 Attachment
              Hi Norman,
               
              The DC gain of each of op-amp is about right.
               
              When you checked for the AC I and Q outputs was it at pins 1 and 7 of the dual op-amp each with reference to circuit ground or at the tip and ring connections beyond SMT caps C16 and C17?  Also, what load did you have on the I and Q output lines?
               
              73,
              Tony KB9YIG
              ----- Original Message -----
              Sent: Monday, December 01, 2008 11:44 AM
              Subject: [softrock40] Re: Troubleshooting Softrock lite RX


              Hi Tony

              pin 1 goes from 2.49 to 3.73V with 10K at pin 2

              pin 7 goes from 2.49 to 3.89 with 10K at pin 6

              Norman

              --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@...> wrote:
              >
              > Hi Norman,
              >
              > Please repeat the DC gain test for the dual op-amp. A 10k resistor
              to ground at pin 2 or pin 6 should result in a voltage change of 1.25
              volts at pin 1 or pin 7 respectively.
              >
              > 73,
              > Tony KB9YIG
              > ----- Original Message -----
              > From: norman.billingham
              > To: softrock40@yahoogro ups.com
              > Sent: Monday, December 01, 2008 10:20 AM
              > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
              >
              >
              > Hi Tony
              >
              > Thanks for coming back so fast
              >
              > This is a 6.0 board so I assume you mean C12 and C13, the two
              0.047
              > uF decouplers? With my scope AC coupled and on its best
              sensitvity,
              > and 50mV of RF on the input all I can see there (or at pins 7 and
              9
              > of U4) is about 20 mV of local oscillator frequency. Likewise at
              > pins 2 and 6 of U5.
              >
              > Pin 1 of U5 is producing nothing and pin 7 has a nice strong Q
              signal
              > at just the right audio frequency.
              >
              > 73
              >
              > Norman
              >
              > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
              > >
              > > Hi Norman,
              > >
              > > How do the signals look on C11 and C13 with reference to
              circuit
              > ground when you have an RF input to the antenna terminals?
              > >
              > > 73,
              > > Tony KB9YIG
              > > ----- Original Message -----
              > > From: norman.billingham
              > > To: softrock40@yahoogro ups.com
              > > Sent: Monday, December 01, 2008 7:32 AM
              > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
              > >
              > >
              > > Dear Tony
              > >
              > > OK I'm really lost now.
              > >
              > > Carefully checked all component values and soldering of T1
              leads -
              >
              > > all seems OK. Checked all leads and for solder bridges with
              high
              > > magnification and all seems OK.
              > >
              > > With no power and no signal there is continuity between the two
              > ends
              > > of T1. There is 20 ohms between pins 11 and 12 of U4 and also
              > > between pins 3 and 6.
              > >
              > > There is 774 ohms between CT of T1 and pin 8 of U5, and
              > essentially
              > > zero ohms between CT of T1 and pins 3 and 5 of U5.
              > >
              > > With no power and 1V p/p at 7.1MHz on the antenna there are
              > > symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6
              on
              > U4 -
              > > all suggests T1 is OK.
              > >
              > > With power on the board and no signal, there is 5.4V p/p at
              7.15
              > MHZ
              > > on the two test points on the board - square wave and 90 phase
              > > shifted and these signals are also on pins 2 and 14 of U4.
              > >
              > > With power on and around 50 mV ont he antenna at 7.15 Mhz there
              > is
              > > about 1V of AF on the Q line and essentially nothing on the I
              > line.
              > >
              > > When I measured the voltahes around U%, all were OK but
              > the "normal"
              > > values (both 2.47V) both went to 4.93 when a 2.6K resistor was
              > used
              > > to bridge the inputs - Robbie's program predicts 3.41V.
              > >
              > > Is it possible that one channel of U5 just isn't working? or is
              > > there some other possible fault?
              > >
              > > Any ides gratefully received
              > >
              > > TIA
              > >
              > > Norman
              > >
              > > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
              > > >
              > > > Hi Norman,
              > > >
              > > > Please check the soldering around T1 and make sure the
              resistor
              > > values are according to the schematic.
              > > >
              > > > 73,
              > > > Tony KB9YIG
              > > > ----- Original Message -----
              > > > From: norman.billingham
              > > > To: softrock40@yahoogro ups.com
              > > > Sent: Sunday, November 30, 2008 12:53 PM
              > > > Subject: [softrock40] Troubleshooting Softrock lite RX
              > > >
              > > >
              > > > Dear all
              > > >
              > > > Hopefully someone can offer words of help to a non-expert.
              > > >
              > > > I just finished my second softrock, using a V6.0 kit I've had
              > for
              > > a
              > > > while.
              > > >
              > > > When I inject about 50mV of signal into the antenna at about
              > > 16kHz
              > > > off centre, I get a beautiful sine wave at both I and Q and
              90o
              > > phase
              > > > shift but the p/p voltage on Q is about 3.5 V and on I is
              only
              > > around
              > > > 50mV.
              > > >
              > > > I followed the detailed instructions and tests on WB5RVZ's
              > great
              > > > pages and all checked out OK except for:
              > > >
              > > > The op-amps. All voltages were OK but the "normal" values
              (both
              > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
              > bridge
              > > the
              > > > inputs - Robbie's program predicts 3.41V
              > > >
              > > > I measure 500mV at pins 1 and 15 on the mixer where Robbie's
              > > values
              > > > are 45 mV - looking at the circuit, these pins are both on an
              > > 1/11K
              > > > potential divider from the 5V rail and 500mV is the
              calculated
              > > value.
              > > >
              > > > I've checked all the component values and soldering around
              the
              > op
              > > > amps and can't find a problem.
              > > >
              > > > Anyone any good ideas please?
              > > >
              > > > Thanks in advance
              > > >
              > > > Norman (M0EBI)
              > > >
              > >
              >

            • norman.billingham
              Hi Tony There is a fine strong signal on pin 7 and on the output side of the capacitor. There is no signal at all on pin 1 or on the output lead. All measured
              Message 6 of 20 , Dec 1, 2008
              • 0 Attachment
                Hi Tony

                There is a fine strong signal on pin 7 and on the output side of the
                capacitor. There is no signal at all on pin 1 or on the output lead.

                All measured wrt ground at the screen connection for I and Q lines.

                Only load is the scope probe - at the moment I just have bits of wire
                soldered into the I and Q outputs to provide test points before I
                mount the board properly in a box and put in the audio cable.

                Thanks for all the help

                73 Norman

                --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                >
                > Hi Norman,
                >
                > The DC gain of each of op-amp is about right.
                >
                > When you checked for the AC I and Q outputs was it at pins 1 and 7
                of the dual op-amp each with reference to circuit ground or at the
                tip and ring connections beyond SMT caps C16 and C17? Also, what
                load did you have on the I and Q output lines?
                >
                > 73,
                > Tony KB9YIG
                > ----- Original Message -----
                > From: norman.billingham
                > To: softrock40@yahoogroups.com
                > Sent: Monday, December 01, 2008 11:44 AM
                > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                >
                >
                >
                > Hi Tony
                >
                > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                >
                > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                >
                > Norman
                >
                > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                > >
                > > Hi Norman,
                > >
                > > Please repeat the DC gain test for the dual op-amp. A 10k
                resistor
                > to ground at pin 2 or pin 6 should result in a voltage change of
                1.25
                > volts at pin 1 or pin 7 respectively.
                > >
                > > 73,
                > > Tony KB9YIG
                > > ----- Original Message -----
                > > From: norman.billingham
                > > To: softrock40@yahoogroups.com
                > > Sent: Monday, December 01, 2008 10:20 AM
                > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                > >
                > >
                > > Hi Tony
                > >
                > > Thanks for coming back so fast
                > >
                > > This is a 6.0 board so I assume you mean C12 and C13, the two
                > 0.047
                > > uF decouplers? With my scope AC coupled and on its best
                > sensitvity,
                > > and 50mV of RF on the input all I can see there (or at pins 7
                and
                > 9
                > > of U4) is about 20 mV of local oscillator frequency. Likewise
                at
                > > pins 2 and 6 of U5.
                > >
                > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong Q
                > signal
                > > at just the right audio frequency.
                > >
                > > 73
                > >
                > > Norman
                > >
                > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                > > >
                > > > Hi Norman,
                > > >
                > > > How do the signals look on C11 and C13 with reference to
                > circuit
                > > ground when you have an RF input to the antenna terminals?
                > > >
                > > > 73,
                > > > Tony KB9YIG
                > > > ----- Original Message -----
                > > > From: norman.billingham
                > > > To: softrock40@yahoogroups.com
                > > > Sent: Monday, December 01, 2008 7:32 AM
                > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                > > >
                > > >
                > > > Dear Tony
                > > >
                > > > OK I'm really lost now.
                > > >
                > > > Carefully checked all component values and soldering of T1
                > leads -
                > >
                > > > all seems OK. Checked all leads and for solder bridges with
                > high
                > > > magnification and all seems OK.
                > > >
                > > > With no power and no signal there is continuity between the
                two
                > > ends
                > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and also
                > > > between pins 3 and 6.
                > > >
                > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                > > essentially
                > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                > > >
                > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                > > > symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6
                > on
                > > U4 -
                > > > all suggests T1 is OK.
                > > >
                > > > With power on the board and no signal, there is 5.4V p/p at
                > 7.15
                > > MHZ
                > > > on the two test points on the board - square wave and 90
                phase
                > > > shifted and these signals are also on pins 2 and 14 of U4.
                > > >
                > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                there
                > > is
                > > > about 1V of AF on the Q line and essentially nothing on the I
                > > line.
                > > >
                > > > When I measured the voltahes around U%, all were OK but
                > > the "normal"
                > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                was
                > > used
                > > > to bridge the inputs - Robbie's program predicts 3.41V.
                > > >
                > > > Is it possible that one channel of U5 just isn't working? or
                is
                > > > there some other possible fault?
                > > >
                > > > Any ides gratefully received
                > > >
                > > > TIA
                > > >
                > > > Norman
                > > >
                > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                wrote:
                > > > >
                > > > > Hi Norman,
                > > > >
                > > > > Please check the soldering around T1 and make sure the
                > resistor
                > > > values are according to the schematic.
                > > > >
                > > > > 73,
                > > > > Tony KB9YIG
                > > > > ----- Original Message -----
                > > > > From: norman.billingham
                > > > > To: softrock40@yahoogroups.com
                > > > > Sent: Sunday, November 30, 2008 12:53 PM
                > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                > > > >
                > > > >
                > > > > Dear all
                > > > >
                > > > > Hopefully someone can offer words of help to a non-expert.
                > > > >
                > > > > I just finished my second softrock, using a V6.0 kit I've
                had
                > > for
                > > > a
                > > > > while.
                > > > >
                > > > > When I inject about 50mV of signal into the antenna at
                about
                > > > 16kHz
                > > > > off centre, I get a beautiful sine wave at both I and Q and
                > 90o
                > > > phase
                > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                > only
                > > > around
                > > > > 50mV.
                > > > >
                > > > > I followed the detailed instructions and tests on WB5RVZ's
                > > great
                > > > > pages and all checked out OK except for:
                > > > >
                > > > > The op-amps. All voltages were OK but the "normal" values
                > (both
                > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                > > bridge
                > > > the
                > > > > inputs - Robbie's program predicts 3.41V
                > > > >
                > > > > I measure 500mV at pins 1 and 15 on the mixer where
                Robbie's
                > > > values
                > > > > are 45 mV - looking at the circuit, these pins are both on
                an
                > > > 1/11K
                > > > > potential divider from the 5V rail and 500mV is the
                > calculated
                > > > value.
                > > > >
                > > > > I've checked all the component values and soldering around
                > the
                > > op
                > > > > amps and can't find a problem.
                > > > >
                > > > > Anyone any good ideas please?
                > > > >
                > > > > Thanks in advance
                > > > >
                > > > > Norman (M0EBI)
                > > > >
                > > >
                > >
                >
              • Tony Parks
                Hi Norman, With DC gain of each op-amp about right, it seems that R9 has a larger resistance than 10 ohms, or C14 has more capacitance than 220 pF, or there is
                Message 7 of 20 , Dec 1, 2008
                • 0 Attachment
                  Hi Norman,
                   
                  With DC gain of each op-amp about right, it seems that R9 has a larger resistance than 10 ohms, or C14 has more capacitance than 220 pF, or there is an AC load on the pin 1 output of U5.  (Also still the possibility there is a problem with U5.)  I would suggest removing C16 first to see if the AC voltage at pin 1 of U5 increases with the RF test signal input you are using.  Next, remove C14.
                   
                  73,
                  Tony KB9YIG
                   
                  ----- Original Message -----
                  Sent: Monday, December 01, 2008 1:27 PM
                  Subject: [softrock40] Re: Troubleshooting Softrock lite RX



                  Hi Tony

                  There is a fine strong signal on pin 7 and on the output side of the
                  capacitor. There is no signal at all on pin 1 or on the output lead.

                  All measured wrt ground at the screen connection for I and Q lines.

                  Only load is the scope probe - at the moment I just have bits of wire
                  soldered into the I and Q outputs to provide test points before I
                  mount the board properly in a box and put in the audio cable.

                  Thanks for all the help

                  73 Norman

                  --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@...> wrote:
                  >
                  > Hi Norman,
                  >
                  > The DC gain of each of op-amp is about right.
                  >
                  > When you checked for the AC I and Q outputs was it at pins 1 and 7
                  of the dual op-amp each with reference to circuit ground or at the
                  tip and ring connections beyond SMT caps C16 and C17? Also, what
                  load did you have on the I and Q output lines?
                  >
                  > 73,
                  > Tony KB9YIG
                  > ----- Original Message -----
                  > From: norman.billingham
                  > To: softrock40@yahoogro ups.com
                  > Sent: Monday, December 01, 2008 11:44 AM
                  > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                  >
                  >
                  >
                  > Hi Tony
                  >
                  > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                  >
                  > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                  >
                  > Norman
                  >
                  > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
                  > >
                  > > Hi Norman,
                  > >
                  > > Please repeat the DC gain test for the dual op-amp. A 10k
                  resistor
                  > to ground at pin 2 or pin 6 should result in a voltage change of
                  1.25
                  > volts at pin 1 or pin 7 respectively.
                  > >
                  > > 73,
                  > > Tony KB9YIG
                  > > ----- Original Message -----
                  > > From: norman.billingham
                  > > To: softrock40@yahoogro ups.com
                  > > Sent: Monday, December 01, 2008 10:20 AM
                  > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                  > >
                  > >
                  > > Hi Tony
                  > >
                  > > Thanks for coming back so fast
                  > >
                  > > This is a 6.0 board so I assume you mean C12 and C13, the two
                  > 0.047
                  > > uF decouplers? With my scope AC coupled and on its best
                  > sensitvity,
                  > > and 50mV of RF on the input all I can see there (or at pins 7
                  and
                  > 9
                  > > of U4) is about 20 mV of local oscillator frequency. Likewise
                  at
                  > > pins 2 and 6 of U5.
                  > >
                  > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong Q
                  > signal
                  > > at just the right audio frequency.
                  > >
                  > > 73
                  > >
                  > > Norman
                  > >
                  > > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
                  > > >
                  > > > Hi Norman,
                  > > >
                  > > > How do the signals look on C11 and C13 with reference to
                  > circuit
                  > > ground when you have an RF input to the antenna terminals?
                  > > >
                  > > > 73,
                  > > > Tony KB9YIG
                  > > > ----- Original Message -----
                  > > > From: norman.billingham
                  > > > To: softrock40@yahoogro ups.com
                  > > > Sent: Monday, December 01, 2008 7:32 AM
                  > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                  > > >
                  > > >
                  > > > Dear Tony
                  > > >
                  > > > OK I'm really lost now.
                  > > >
                  > > > Carefully checked all component values and soldering of T1
                  > leads -
                  > >
                  > > > all seems OK. Checked all leads and for solder bridges with
                  > high
                  > > > magnification and all seems OK.
                  > > >
                  > > > With no power and no signal there is continuity between the
                  two
                  > > ends
                  > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and also
                  > > > between pins 3 and 6.
                  > > >
                  > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                  > > essentially
                  > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                  > > >
                  > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                  > > > symmetrical 450mV signals 180 out of phase at 11/2 and at 3/6
                  > on
                  > > U4 -
                  > > > all suggests T1 is OK.
                  > > >
                  > > > With power on the board and no signal, there is 5.4V p/p at
                  > 7.15
                  > > MHZ
                  > > > on the two test points on the board - square wave and 90
                  phase
                  > > > shifted and these signals are also on pins 2 and 14 of U4.
                  > > >
                  > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                  there
                  > > is
                  > > > about 1V of AF on the Q line and essentially nothing on the I
                  > > line.
                  > > >
                  > > > When I measured the voltahes around U%, all were OK but
                  > > the "normal"
                  > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                  was
                  > > used
                  > > > to bridge the inputs - Robbie's program predicts 3.41V.
                  > > >
                  > > > Is it possible that one channel of U5 just isn't working? or
                  is
                  > > > there some other possible fault?
                  > > >
                  > > > Any ides gratefully received
                  > > >
                  > > > TIA
                  > > >
                  > > > Norman
                  > > >
                  > > > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@>
                  wrote:
                  > > > >
                  > > > > Hi Norman,
                  > > > >
                  > > > > Please check the soldering around T1 and make sure the
                  > resistor
                  > > > values are according to the schematic.
                  > > > >
                  > > > > 73,
                  > > > > Tony KB9YIG
                  > > > > ----- Original Message -----
                  > > > > From: norman.billingham
                  > > > > To: softrock40@yahoogro ups.com
                  > > > > Sent: Sunday, November 30, 2008 12:53 PM
                  > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                  > > > >
                  > > > >
                  > > > > Dear all
                  > > > >
                  > > > > Hopefully someone can offer words of help to a non-expert.
                  > > > >
                  > > > > I just finished my second softrock, using a V6.0 kit I've
                  had
                  > > for
                  > > > a
                  > > > > while.
                  > > > >
                  > > > > When I inject about 50mV of signal into the antenna at
                  about
                  > > > 16kHz
                  > > > > off centre, I get a beautiful sine wave at both I and Q and
                  > 90o
                  > > > phase
                  > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                  > only
                  > > > around
                  > > > > 50mV.
                  > > > >
                  > > > > I followed the detailed instructions and tests on WB5RVZ's
                  > > great
                  > > > > pages and all checked out OK except for:
                  > > > >
                  > > > > The op-amps. All voltages were OK but the "normal" values
                  > (both
                  > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                  > > bridge
                  > > > the
                  > > > > inputs - Robbie's program predicts 3.41V
                  > > > >
                  > > > > I measure 500mV at pins 1 and 15 on the mixer where
                  Robbie's
                  > > > values
                  > > > > are 45 mV - looking at the circuit, these pins are both on
                  an
                  > > > 1/11K
                  > > > > potential divider from the 5V rail and 500mV is the
                  > calculated
                  > > > value.
                  > > > >
                  > > > > I've checked all the component values and soldering around
                  > the
                  > > op
                  > > > > amps and can't find a problem.
                  > > > >
                  > > > > Anyone any good ideas please?
                  > > > >
                  > > > > Thanks in advance
                  > > > >
                  > > > > Norman (M0EBI)
                  > > > >
                  > > >
                  > >
                  >

                • norman.billingham
                  Thanks Tony. It all checks out visually so I ll take out the capacitors tomorrow and see what happens. I ll probably order up a new U5 just in case. Our local
                  Message 8 of 20 , Dec 1, 2008
                  • 0 Attachment
                    Thanks Tony.

                    It all checks out visually so I'll take out the capacitors tomorrow
                    and see what happens.

                    I'll probably order up a new U5 just in case. Our local stockist
                    lists 3 versions of the LTC6241, with numbers LTC6241CS8,
                    LTC6241HVCS8 and LTC6241HVIS8. The first two seem to be identical
                    except for a wider temperature range for the second - both are
                    described as type "low noise". The third is decribed as
                    type "CMOS". Does it matter which I get?

                    Norman






                    --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                    >
                    > Hi Norman,
                    >
                    > With DC gain of each op-amp about right, it seems that R9 has a
                    larger resistance than 10 ohms, or C14 has more capacitance than 220
                    pF, or there is an AC load on the pin 1 output of U5. (Also still
                    the possibility there is a problem with U5.) I would suggest
                    removing C16 first to see if the AC voltage at pin 1 of U5 increases
                    with the RF test signal input you are using. Next, remove C14.
                    >
                    > 73,
                    > Tony KB9YIG
                    >
                    > ----- Original Message -----
                    > From: norman.billingham
                    > To: softrock40@yahoogroups.com
                    > Sent: Monday, December 01, 2008 1:27 PM
                    > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                    >
                    >
                    >
                    >
                    > Hi Tony
                    >
                    > There is a fine strong signal on pin 7 and on the output side of
                    the
                    > capacitor. There is no signal at all on pin 1 or on the output
                    lead.
                    >
                    > All measured wrt ground at the screen connection for I and Q
                    lines.
                    >
                    > Only load is the scope probe - at the moment I just have bits of
                    wire
                    > soldered into the I and Q outputs to provide test points before I
                    > mount the board properly in a box and put in the audio cable.
                    >
                    > Thanks for all the help
                    >
                    > 73 Norman
                    >
                    > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                    > >
                    > > Hi Norman,
                    > >
                    > > The DC gain of each of op-amp is about right.
                    > >
                    > > When you checked for the AC I and Q outputs was it at pins 1
                    and 7
                    > of the dual op-amp each with reference to circuit ground or at
                    the
                    > tip and ring connections beyond SMT caps C16 and C17? Also, what
                    > load did you have on the I and Q output lines?
                    > >
                    > > 73,
                    > > Tony KB9YIG
                    > > ----- Original Message -----
                    > > From: norman.billingham
                    > > To: softrock40@yahoogroups.com
                    > > Sent: Monday, December 01, 2008 11:44 AM
                    > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                    > >
                    > >
                    > >
                    > > Hi Tony
                    > >
                    > > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                    > >
                    > > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                    > >
                    > > Norman
                    > >
                    > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                    > > >
                    > > > Hi Norman,
                    > > >
                    > > > Please repeat the DC gain test for the dual op-amp. A 10k
                    > resistor
                    > > to ground at pin 2 or pin 6 should result in a voltage change
                    of
                    > 1.25
                    > > volts at pin 1 or pin 7 respectively.
                    > > >
                    > > > 73,
                    > > > Tony KB9YIG
                    > > > ----- Original Message -----
                    > > > From: norman.billingham
                    > > > To: softrock40@yahoogroups.com
                    > > > Sent: Monday, December 01, 2008 10:20 AM
                    > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                    > > >
                    > > >
                    > > > Hi Tony
                    > > >
                    > > > Thanks for coming back so fast
                    > > >
                    > > > This is a 6.0 board so I assume you mean C12 and C13, the two
                    > > 0.047
                    > > > uF decouplers? With my scope AC coupled and on its best
                    > > sensitvity,
                    > > > and 50mV of RF on the input all I can see there (or at pins 7
                    > and
                    > > 9
                    > > > of U4) is about 20 mV of local oscillator frequency. Likewise
                    > at
                    > > > pins 2 and 6 of U5.
                    > > >
                    > > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong
                    Q
                    > > signal
                    > > > at just the right audio frequency.
                    > > >
                    > > > 73
                    > > >
                    > > > Norman
                    > > >
                    > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                    wrote:
                    > > > >
                    > > > > Hi Norman,
                    > > > >
                    > > > > How do the signals look on C11 and C13 with reference to
                    > > circuit
                    > > > ground when you have an RF input to the antenna terminals?
                    > > > >
                    > > > > 73,
                    > > > > Tony KB9YIG
                    > > > > ----- Original Message -----
                    > > > > From: norman.billingham
                    > > > > To: softrock40@yahoogroups.com
                    > > > > Sent: Monday, December 01, 2008 7:32 AM
                    > > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                    > > > >
                    > > > >
                    > > > > Dear Tony
                    > > > >
                    > > > > OK I'm really lost now.
                    > > > >
                    > > > > Carefully checked all component values and soldering of T1
                    > > leads -
                    > > >
                    > > > > all seems OK. Checked all leads and for solder bridges with
                    > > high
                    > > > > magnification and all seems OK.
                    > > > >
                    > > > > With no power and no signal there is continuity between the
                    > two
                    > > > ends
                    > > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and
                    also
                    > > > > between pins 3 and 6.
                    > > > >
                    > > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                    > > > essentially
                    > > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                    > > > >
                    > > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                    > > > > symmetrical 450mV signals 180 out of phase at 11/2 and at
                    3/6
                    > > on
                    > > > U4 -
                    > > > > all suggests T1 is OK.
                    > > > >
                    > > > > With power on the board and no signal, there is 5.4V p/p at
                    > > 7.15
                    > > > MHZ
                    > > > > on the two test points on the board - square wave and 90
                    > phase
                    > > > > shifted and these signals are also on pins 2 and 14 of U4.
                    > > > >
                    > > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                    > there
                    > > > is
                    > > > > about 1V of AF on the Q line and essentially nothing on the
                    I
                    > > > line.
                    > > > >
                    > > > > When I measured the voltahes around U%, all were OK but
                    > > > the "normal"
                    > > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                    > was
                    > > > used
                    > > > > to bridge the inputs - Robbie's program predicts 3.41V.
                    > > > >
                    > > > > Is it possible that one channel of U5 just isn't working?
                    or
                    > is
                    > > > > there some other possible fault?
                    > > > >
                    > > > > Any ides gratefully received
                    > > > >
                    > > > > TIA
                    > > > >
                    > > > > Norman
                    > > > >
                    > > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                    > wrote:
                    > > > > >
                    > > > > > Hi Norman,
                    > > > > >
                    > > > > > Please check the soldering around T1 and make sure the
                    > > resistor
                    > > > > values are according to the schematic.
                    > > > > >
                    > > > > > 73,
                    > > > > > Tony KB9YIG
                    > > > > > ----- Original Message -----
                    > > > > > From: norman.billingham
                    > > > > > To: softrock40@yahoogroups.com
                    > > > > > Sent: Sunday, November 30, 2008 12:53 PM
                    > > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                    > > > > >
                    > > > > >
                    > > > > > Dear all
                    > > > > >
                    > > > > > Hopefully someone can offer words of help to a non-expert.
                    > > > > >
                    > > > > > I just finished my second softrock, using a V6.0 kit I've
                    > had
                    > > > for
                    > > > > a
                    > > > > > while.
                    > > > > >
                    > > > > > When I inject about 50mV of signal into the antenna at
                    > about
                    > > > > 16kHz
                    > > > > > off centre, I get a beautiful sine wave at both I and Q
                    and
                    > > 90o
                    > > > > phase
                    > > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                    > > only
                    > > > > around
                    > > > > > 50mV.
                    > > > > >
                    > > > > > I followed the detailed instructions and tests on
                    WB5RVZ's
                    > > > great
                    > > > > > pages and all checked out OK except for:
                    > > > > >
                    > > > > > The op-amps. All voltages were OK but the "normal" values
                    > > (both
                    > > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                    > > > bridge
                    > > > > the
                    > > > > > inputs - Robbie's program predicts 3.41V
                    > > > > >
                    > > > > > I measure 500mV at pins 1 and 15 on the mixer where
                    > Robbie's
                    > > > > values
                    > > > > > are 45 mV - looking at the circuit, these pins are both
                    on
                    > an
                    > > > > 1/11K
                    > > > > > potential divider from the 5V rail and 500mV is the
                    > > calculated
                    > > > > value.
                    > > > > >
                    > > > > > I've checked all the component values and soldering
                    around
                    > > the
                    > > > op
                    > > > > > amps and can't find a problem.
                    > > > > >
                    > > > > > Anyone any good ideas please?
                    > > > > >
                    > > > > > Thanks in advance
                    > > > > >
                    > > > > > Norman (M0EBI)
                    > > > > >
                    > > > >
                    > > >
                    > >
                    >
                  • Tony Parks
                    Hi Norman, The TLC6241CS8 should do the job if the op-amp is needing to be replaced. 73, Tony KB9YIG ... From: norman.billingham To: softrock40@yahoogroups.com
                    Message 9 of 20 , Dec 1, 2008
                    • 0 Attachment
                      Hi Norman,
                       
                      The TLC6241CS8 should do the job if the op-amp is needing to be replaced.
                       
                      73,
                      Tony KB9YIG
                      ----- Original Message -----
                      Sent: Monday, December 01, 2008 3:05 PM
                      Subject: [softrock40] Re: Troubleshooting Softrock lite RX

                      Thanks Tony.

                      It all checks out visually so I'll take out the capacitors tomorrow
                      and see what happens.

                      I'll probably order up a new U5 just in case. Our local stockist
                      lists 3 versions of the LTC6241, with numbers LTC6241CS8,
                      LTC6241HVCS8 and LTC6241HVIS8. The first two seem to be identical
                      except for a wider temperature range for the second - both are
                      described as type "low noise". The third is decribed as
                      type "CMOS". Does it matter which I get?

                      Norman

                      --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@...> wrote:
                      >
                      > Hi Norman,
                      >
                      > With DC gain of each op-amp about right, it seems that R9 has a
                      larger resistance than 10 ohms, or C14 has more capacitance than 220
                      pF, or there is an AC load on the pin 1 output of U5. (Also still
                      the possibility there is a problem with U5.) I would suggest
                      removing C16 first to see if the AC voltage at pin 1 of U5 increases
                      with the RF test signal input you are using. Next, remove C14.
                      >
                      > 73,
                      > Tony KB9YIG
                      >
                      > ----- Original Message -----
                      > From: norman.billingham
                      > To: softrock40@yahoogro ups.com
                      > Sent: Monday, December 01, 2008 1:27 PM
                      > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                      >
                      >
                      >
                      >
                      > Hi Tony
                      >
                      > There is a fine strong signal on pin 7 and on the output side of
                      the
                      > capacitor. There is no signal at all on pin 1 or on the output
                      lead.
                      >
                      > All measured wrt ground at the screen connection for I and Q
                      lines.
                      >
                      > Only load is the scope probe - at the moment I just have bits of
                      wire
                      > soldered into the I and Q outputs to provide test points before I
                      > mount the board properly in a box and put in the audio cable.
                      >
                      > Thanks for all the help
                      >
                      > 73 Norman
                      >
                      > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
                      > >
                      > > Hi Norman,
                      > >
                      > > The DC gain of each of op-amp is about right.
                      > >
                      > > When you checked for the AC I and Q outputs was it at pins 1
                      and 7
                      > of the dual op-amp each with reference to circuit ground or at
                      the
                      > tip and ring connections beyond SMT caps C16 and C17? Also, what
                      > load did you have on the I and Q output lines?
                      > >
                      > > 73,
                      > > Tony KB9YIG
                      > > ----- Original Message -----
                      > > From: norman.billingham
                      > > To: softrock40@yahoogro ups.com
                      > > Sent: Monday, December 01, 2008 11:44 AM
                      > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                      > >
                      > >
                      > >
                      > > Hi Tony
                      > >
                      > > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                      > >
                      > > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                      > >
                      > > Norman
                      > >
                      > > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@> wrote:
                      > > >
                      > > > Hi Norman,
                      > > >
                      > > > Please repeat the DC gain test for the dual op-amp. A 10k
                      > resistor
                      > > to ground at pin 2 or pin 6 should result in a voltage change
                      of
                      > 1.25
                      > > volts at pin 1 or pin 7 respectively.
                      > > >
                      > > > 73,
                      > > > Tony KB9YIG
                      > > > ----- Original Message -----
                      > > > From: norman.billingham
                      > > > To: softrock40@yahoogro ups.com
                      > > > Sent: Monday, December 01, 2008 10:20 AM
                      > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                      > > >
                      > > >
                      > > > Hi Tony
                      > > >
                      > > > Thanks for coming back so fast
                      > > >
                      > > > This is a 6.0 board so I assume you mean C12 and C13, the two
                      > > 0.047
                      > > > uF decouplers? With my scope AC coupled and on its best
                      > > sensitvity,
                      > > > and 50mV of RF on the input all I can see there (or at pins 7
                      > and
                      > > 9
                      > > > of U4) is about 20 mV of local oscillator frequency. Likewise
                      > at
                      > > > pins 2 and 6 of U5.
                      > > >
                      > > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong
                      Q
                      > > signal
                      > > > at just the right audio frequency.
                      > > >
                      > > > 73
                      > > >
                      > > > Norman
                      > > >
                      > > > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@>
                      wrote:
                      > > > >
                      > > > > Hi Norman,
                      > > > >
                      > > > > How do the signals look on C11 and C13 with reference to
                      > > circuit
                      > > > ground when you have an RF input to the antenna terminals?
                      > > > >
                      > > > > 73,
                      > > > > Tony KB9YIG
                      > > > > ----- Original Message -----
                      > > > > From: norman.billingham
                      > > > > To: softrock40@yahoogro ups.com
                      > > > > Sent: Monday, December 01, 2008 7:32 AM
                      > > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                      > > > >
                      > > > >
                      > > > > Dear Tony
                      > > > >
                      > > > > OK I'm really lost now.
                      > > > >
                      > > > > Carefully checked all component values and soldering of T1
                      > > leads -
                      > > >
                      > > > > all seems OK. Checked all leads and for solder bridges with
                      > > high
                      > > > > magnification and all seems OK.
                      > > > >
                      > > > > With no power and no signal there is continuity between the
                      > two
                      > > > ends
                      > > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and
                      also
                      > > > > between pins 3 and 6.
                      > > > >
                      > > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                      > > > essentially
                      > > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                      > > > >
                      > > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                      > > > > symmetrical 450mV signals 180 out of phase at 11/2 and at
                      3/6
                      > > on
                      > > > U4 -
                      > > > > all suggests T1 is OK.
                      > > > >
                      > > > > With power on the board and no signal, there is 5.4V p/p at
                      > > 7.15
                      > > > MHZ
                      > > > > on the two test points on the board - square wave and 90
                      > phase
                      > > > > shifted and these signals are also on pins 2 and 14 of U4.
                      > > > >
                      > > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                      > there
                      > > > is
                      > > > > about 1V of AF on the Q line and essentially nothing on the
                      I
                      > > > line.
                      > > > >
                      > > > > When I measured the voltahes around U%, all were OK but
                      > > > the "normal"
                      > > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                      > was
                      > > > used
                      > > > > to bridge the inputs - Robbie's program predicts 3.41V.
                      > > > >
                      > > > > Is it possible that one channel of U5 just isn't working?
                      or
                      > is
                      > > > > there some other possible fault?
                      > > > >
                      > > > > Any ides gratefully received
                      > > > >
                      > > > > TIA
                      > > > >
                      > > > > Norman
                      > > > >
                      > > > > --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@>
                      > wrote:
                      > > > > >
                      > > > > > Hi Norman,
                      > > > > >
                      > > > > > Please check the soldering around T1 and make sure the
                      > > resistor
                      > > > > values are according to the schematic.
                      > > > > >
                      > > > > > 73,
                      > > > > > Tony KB9YIG
                      > > > > > ----- Original Message -----
                      > > > > > From: norman.billingham
                      > > > > > To: softrock40@yahoogro ups.com
                      > > > > > Sent: Sunday, November 30, 2008 12:53 PM
                      > > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                      > > > > >
                      > > > > >
                      > > > > > Dear all
                      > > > > >
                      > > > > > Hopefully someone can offer words of help to a non-expert.
                      > > > > >
                      > > > > > I just finished my second softrock, using a V6.0 kit I've
                      > had
                      > > > for
                      > > > > a
                      > > > > > while.
                      > > > > >
                      > > > > > When I inject about 50mV of signal into the antenna at
                      > about
                      > > > > 16kHz
                      > > > > > off centre, I get a beautiful sine wave at both I and Q
                      and
                      > > 90o
                      > > > > phase
                      > > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                      > > only
                      > > > > around
                      > > > > > 50mV.
                      > > > > >
                      > > > > > I followed the detailed instructions and tests on
                      WB5RVZ's
                      > > > great
                      > > > > > pages and all checked out OK except for:
                      > > > > >
                      > > > > > The op-amps. All voltages were OK but the "normal" values
                      > > (both
                      > > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                      > > > bridge
                      > > > > the
                      > > > > > inputs - Robbie's program predicts 3.41V
                      > > > > >
                      > > > > > I measure 500mV at pins 1 and 15 on the mixer where
                      > Robbie's
                      > > > > values
                      > > > > > are 45 mV - looking at the circuit, these pins are both
                      on
                      > an
                      > > > > 1/11K
                      > > > > > potential divider from the 5V rail and 500mV is the
                      > > calculated
                      > > > > value.
                      > > > > >
                      > > > > > I've checked all the component values and soldering
                      around
                      > > the
                      > > > op
                      > > > > > amps and can't find a problem.
                      > > > > >
                      > > > > > Anyone any good ideas please?
                      > > > > >
                      > > > > > Thanks in advance
                      > > > > >
                      > > > > > Norman (M0EBI)
                      > > > > >
                      > > > >
                      > > >
                      > >
                      >

                    • Jose Bonanca
                      Norman please check out what chip you need if it is the audio chip should be LTC 6231 and not 6241. LTC6231 is dual and 6241 is one only audio amp. 73 On Mon,
                      Message 10 of 20 , Dec 1, 2008
                      • 0 Attachment
                        Norman please check out what chip you need if it is the audio chip should be LTC 6231 and not 6241.
                        LTC6231 is dual and 6241 is one only audio amp.
                        73

                        On Mon, Dec 1, 2008 at 8:05 PM, norman.billingham <norman.billingham@...> wrote:

                        Thanks Tony.

                        It all checks out visually so I'll take out the capacitors tomorrow
                        and see what happens.

                        I'll probably order up a new U5 just in case. Our local stockist
                        lists 3 versions of the LTC6241, with numbers LTC6241CS8,
                        LTC6241HVCS8 and LTC6241HVIS8. The first two seem to be identical
                        except for a wider temperature range for the second - both are
                        described as type "low noise". The third is decribed as
                        type "CMOS". Does it matter which I get?

                        Norman

                        --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                        >
                        > Hi Norman,
                        >
                        > With DC gain of each op-amp about right, it seems that R9 has a
                        larger resistance than 10 ohms, or C14 has more capacitance than 220
                        pF, or there is an AC load on the pin 1 output of U5. (Also still
                        the possibility there is a problem with U5.) I would suggest
                        removing C16 first to see if the AC voltage at pin 1 of U5 increases
                        with the RF test signal input you are using. Next, remove C14.
                        >
                        > 73,
                        > Tony KB9YIG
                        >
                        > ----- Original Message -----
                        > From: norman.billingham
                        > To: softrock40@yahoogroups.com
                        > Sent: Monday, December 01, 2008 1:27 PM
                        > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                        >
                        >
                        >
                        >
                        > Hi Tony
                        >
                        > There is a fine strong signal on pin 7 and on the output side of
                        the
                        > capacitor. There is no signal at all on pin 1 or on the output
                        lead.
                        >
                        > All measured wrt ground at the screen connection for I and Q
                        lines.
                        >
                        > Only load is the scope probe - at the moment I just have bits of
                        wire
                        > soldered into the I and Q outputs to provide test points before I
                        > mount the board properly in a box and put in the audio cable.
                        >
                        > Thanks for all the help
                        >
                        > 73 Norman
                        >
                        > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                        > >
                        > > Hi Norman,
                        > >
                        > > The DC gain of each of op-amp is about right.
                        > >
                        > > When you checked for the AC I and Q outputs was it at pins 1
                        and 7
                        > of the dual op-amp each with reference to circuit ground or at
                        the
                        > tip and ring connections beyond SMT caps C16 and C17? Also, what
                        > load did you have on the I and Q output lines?
                        > >
                        > > 73,
                        > > Tony KB9YIG
                        > > ----- Original Message -----
                        > > From: norman.billingham
                        > > To: softrock40@yahoogroups.com
                        > > Sent: Monday, December 01, 2008 11:44 AM
                        > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                        > >
                        > >
                        > >
                        > > Hi Tony
                        > >
                        > > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                        > >
                        > > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                        > >
                        > > Norman
                        > >
                        > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                        > > >
                        > > > Hi Norman,
                        > > >
                        > > > Please repeat the DC gain test for the dual op-amp. A 10k
                        > resistor
                        > > to ground at pin 2 or pin 6 should result in a voltage change
                        of
                        > 1.25
                        > > volts at pin 1 or pin 7 respectively.
                        > > >
                        > > > 73,
                        > > > Tony KB9YIG
                        > > > ----- Original Message -----
                        > > > From: norman.billingham
                        > > > To: softrock40@yahoogroups.com
                        > > > Sent: Monday, December 01, 2008 10:20 AM
                        > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                        > > >
                        > > >
                        > > > Hi Tony
                        > > >
                        > > > Thanks for coming back so fast
                        > > >
                        > > > This is a 6.0 board so I assume you mean C12 and C13, the two
                        > > 0.047
                        > > > uF decouplers? With my scope AC coupled and on its best
                        > > sensitvity,
                        > > > and 50mV of RF on the input all I can see there (or at pins 7
                        > and
                        > > 9
                        > > > of U4) is about 20 mV of local oscillator frequency. Likewise
                        > at
                        > > > pins 2 and 6 of U5.
                        > > >
                        > > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong
                        Q
                        > > signal
                        > > > at just the right audio frequency.
                        > > >
                        > > > 73
                        > > >
                        > > > Norman
                        > > >
                        > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                        wrote:
                        > > > >
                        > > > > Hi Norman,
                        > > > >
                        > > > > How do the signals look on C11 and C13 with reference to
                        > > circuit
                        > > > ground when you have an RF input to the antenna terminals?
                        > > > >
                        > > > > 73,
                        > > > > Tony KB9YIG
                        > > > > ----- Original Message -----
                        > > > > From: norman.billingham
                        > > > > To: softrock40@yahoogroups.com
                        > > > > Sent: Monday, December 01, 2008 7:32 AM
                        > > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                        > > > >
                        > > > >
                        > > > > Dear Tony
                        > > > >
                        > > > > OK I'm really lost now.
                        > > > >
                        > > > > Carefully checked all component values and soldering of T1
                        > > leads -
                        > > >
                        > > > > all seems OK. Checked all leads and for solder bridges with
                        > > high
                        > > > > magnification and all seems OK.
                        > > > >
                        > > > > With no power and no signal there is continuity between the
                        > two
                        > > > ends
                        > > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and
                        also
                        > > > > between pins 3 and 6.
                        > > > >
                        > > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                        > > > essentially
                        > > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                        > > > >
                        > > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                        > > > > symmetrical 450mV signals 180 out of phase at 11/2 and at
                        3/6
                        > > on
                        > > > U4 -
                        > > > > all suggests T1 is OK.
                        > > > >
                        > > > > With power on the board and no signal, there is 5.4V p/p at
                        > > 7.15
                        > > > MHZ
                        > > > > on the two test points on the board - square wave and 90
                        > phase
                        > > > > shifted and these signals are also on pins 2 and 14 of U4.
                        > > > >
                        > > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                        > there
                        > > > is
                        > > > > about 1V of AF on the Q line and essentially nothing on the
                        I
                        > > > line.
                        > > > >
                        > > > > When I measured the voltahes around U%, all were OK but
                        > > > the "normal"
                        > > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                        > was
                        > > > used
                        > > > > to bridge the inputs - Robbie's program predicts 3.41V.
                        > > > >
                        > > > > Is it possible that one channel of U5 just isn't working?
                        or
                        > is
                        > > > > there some other possible fault?
                        > > > >
                        > > > > Any ides gratefully received
                        > > > >
                        > > > > TIA
                        > > > >
                        > > > > Norman
                        > > > >
                        > > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                        > wrote:
                        > > > > >
                        > > > > > Hi Norman,
                        > > > > >
                        > > > > > Please check the soldering around T1 and make sure the
                        > > resistor
                        > > > > values are according to the schematic.
                        > > > > >
                        > > > > > 73,
                        > > > > > Tony KB9YIG
                        > > > > > ----- Original Message -----
                        > > > > > From: norman.billingham
                        > > > > > To: softrock40@yahoogroups.com
                        > > > > > Sent: Sunday, November 30, 2008 12:53 PM
                        > > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                        > > > > >
                        > > > > >
                        > > > > > Dear all
                        > > > > >
                        > > > > > Hopefully someone can offer words of help to a non-expert.
                        > > > > >
                        > > > > > I just finished my second softrock, using a V6.0 kit I've
                        > had
                        > > > for
                        > > > > a
                        > > > > > while.
                        > > > > >
                        > > > > > When I inject about 50mV of signal into the antenna at
                        > about
                        > > > > 16kHz
                        > > > > > off centre, I get a beautiful sine wave at both I and Q
                        and
                        > > 90o
                        > > > > phase
                        > > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                        > > only
                        > > > > around
                        > > > > > 50mV.
                        > > > > >
                        > > > > > I followed the detailed instructions and tests on
                        WB5RVZ's
                        > > > great
                        > > > > > pages and all checked out OK except for:
                        > > > > >
                        > > > > > The op-amps. All voltages were OK but the "normal" values
                        > > (both
                        > > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                        > > > bridge
                        > > > > the
                        > > > > > inputs - Robbie's program predicts 3.41V
                        > > > > >
                        > > > > > I measure 500mV at pins 1 and 15 on the mixer where
                        > Robbie's
                        > > > > values
                        > > > > > are 45 mV - looking at the circuit, these pins are both
                        on
                        > an
                        > > > > 1/11K
                        > > > > > potential divider from the 5V rail and 500mV is the
                        > > calculated
                        > > > > value.
                        > > > > >
                        > > > > > I've checked all the component values and soldering
                        around
                        > > the
                        > > > op
                        > > > > > amps and can't find a problem.
                        > > > > >
                        > > > > > Anyone any good ideas please?
                        > > > > >
                        > > > > > Thanks in advance
                        > > > > >
                        > > > > > Norman (M0EBI)
                        > > > > >
                        > > > >
                        > > >
                        > >
                        >




                        --
                        Jose Bonanca  (CT1aos)
                      • Jose Bonanca
                        Well Tony I have here some LT6241 and they are different from LT6231.. So , now are you sure? Regards. ... -- Jose Bonanca (CT1aos)
                        Message 11 of 20 , Dec 1, 2008
                        • 0 Attachment
                          Well Tony I have here some LT6241 and they are different from LT6231..
                          So , now are you sure?
                          Regards.


                           
                          On Mon, Dec 1, 2008 at 8:34 PM, Tony Parks <kb9yig@...> wrote:

                          Hi Norman,
                           
                          The TLC6241CS8 should do the job if the op-amp is needing to be replaced.
                           
                          73,
                          Tony KB9YIG
                          ----- Original Message -----
                          Sent: Monday, December 01, 2008 3:05 PM
                          Subject: [softrock40] Re: Troubleshooting Softrock lite RX

                          Thanks Tony.

                          It all checks out visually so I'll take out the capacitors tomorrow
                          and see what happens.

                          I'll probably order up a new U5 just in case. Our local stockist
                          lists 3 versions of the LTC6241, with numbers LTC6241CS8,
                          LTC6241HVCS8 and LTC6241HVIS8. The first two seem to be identical
                          except for a wider temperature range for the second - both are
                          described as type "low noise". The third is decribed as
                          type "CMOS". Does it matter which I get?

                          Norman

                          --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                          >
                          > Hi Norman,
                          >
                          > With DC gain of each op-amp about right, it seems that R9 has a
                          larger resistance than 10 ohms, or C14 has more capacitance than 220
                          pF, or there is an AC load on the pin 1 output of U5. (Also still
                          the possibility there is a problem with U5.) I would suggest
                          removing C16 first to see if the AC voltage at pin 1 of U5 increases
                          with the RF test signal input you are using. Next, remove C14.
                          >
                          > 73,
                          > Tony KB9YIG
                          >
                          > ----- Original Message -----
                          > From: norman.billingham
                          > To: softrock40@yahoogroups.com
                          > Sent: Monday, December 01, 2008 1:27 PM
                          > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                          >
                          >
                          >
                          >
                          > Hi Tony
                          >
                          > There is a fine strong signal on pin 7 and on the output side of
                          the
                          > capacitor. There is no signal at all on pin 1 or on the output
                          lead.
                          >
                          > All measured wrt ground at the screen connection for I and Q
                          lines.
                          >
                          > Only load is the scope probe - at the moment I just have bits of
                          wire
                          > soldered into the I and Q outputs to provide test points before I
                          > mount the board properly in a box and put in the audio cable.
                          >
                          > Thanks for all the help
                          >
                          > 73 Norman
                          >
                          > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                          > >
                          > > Hi Norman,
                          > >
                          > > The DC gain of each of op-amp is about right.
                          > >
                          > > When you checked for the AC I and Q outputs was it at pins 1
                          and 7
                          > of the dual op-amp each with reference to circuit ground or at
                          the
                          > tip and ring connections beyond SMT caps C16 and C17? Also, what
                          > load did you have on the I and Q output lines?
                          > >
                          > > 73,
                          > > Tony KB9YIG
                          > > ----- Original Message -----
                          > > From: norman.billingham
                          > > To: softrock40@yahoogroups.com
                          > > Sent: Monday, December 01, 2008 11:44 AM
                          > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                          > >
                          > >
                          > >
                          > > Hi Tony
                          > >
                          > > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                          > >
                          > > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                          > >
                          > > Norman
                          > >
                          > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                          > > >
                          > > > Hi Norman,
                          > > >
                          > > > Please repeat the DC gain test for the dual op-amp. A 10k
                          > resistor
                          > > to ground at pin 2 or pin 6 should result in a voltage change
                          of
                          > 1.25
                          > > volts at pin 1 or pin 7 respectively.
                          > > >
                          > > > 73,
                          > > > Tony KB9YIG
                          > > > ----- Original Message -----
                          > > > From: norman.billingham
                          > > > To: softrock40@yahoogroups.com
                          > > > Sent: Monday, December 01, 2008 10:20 AM
                          > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                          > > >
                          > > >
                          > > > Hi Tony
                          > > >
                          > > > Thanks for coming back so fast
                          > > >
                          > > > This is a 6.0 board so I assume you mean C12 and C13, the two
                          > > 0.047
                          > > > uF decouplers? With my scope AC coupled and on its best
                          > > sensitvity,
                          > > > and 50mV of RF on the input all I can see there (or at pins 7
                          > and
                          > > 9
                          > > > of U4) is about 20 mV of local oscillator frequency. Likewise
                          > at
                          > > > pins 2 and 6 of U5.
                          > > >
                          > > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong
                          Q
                          > > signal
                          > > > at just the right audio frequency.
                          > > >
                          > > > 73
                          > > >
                          > > > Norman
                          > > >
                          > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                          wrote:
                          > > > >
                          > > > > Hi Norman,
                          > > > >
                          > > > > How do the signals look on C11 and C13 with reference to
                          > > circuit
                          > > > ground when you have an RF input to the antenna terminals?
                          > > > >
                          > > > > 73,
                          > > > > Tony KB9YIG
                          > > > > ----- Original Message -----
                          > > > > From: norman.billingham
                          > > > > To: softrock40@yahoogroups.com
                          > > > > Sent: Monday, December 01, 2008 7:32 AM
                          > > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                          > > > >
                          > > > >
                          > > > > Dear Tony
                          > > > >
                          > > > > OK I'm really lost now.
                          > > > >
                          > > > > Carefully checked all component values and soldering of T1
                          > > leads -
                          > > >
                          > > > > all seems OK. Checked all leads and for solder bridges with
                          > > high
                          > > > > magnification and all seems OK.
                          > > > >
                          > > > > With no power and no signal there is continuity between the
                          > two
                          > > > ends
                          > > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and
                          also
                          > > > > between pins 3 and 6.
                          > > > >
                          > > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                          > > > essentially
                          > > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                          > > > >
                          > > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                          > > > > symmetrical 450mV signals 180 out of phase at 11/2 and at
                          3/6
                          > > on
                          > > > U4 -
                          > > > > all suggests T1 is OK.
                          > > > >
                          > > > > With power on the board and no signal, there is 5.4V p/p at
                          > > 7.15
                          > > > MHZ
                          > > > > on the two test points on the board - square wave and 90
                          > phase
                          > > > > shifted and these signals are also on pins 2 and 14 of U4.
                          > > > >
                          > > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                          > there
                          > > > is
                          > > > > about 1V of AF on the Q line and essentially nothing on the
                          I
                          > > > line.
                          > > > >
                          > > > > When I measured the voltahes around U%, all were OK but
                          > > > the "normal"
                          > > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                          > was
                          > > > used
                          > > > > to bridge the inputs - Robbie's program predicts 3.41V.
                          > > > >
                          > > > > Is it possible that one channel of U5 just isn't working?
                          or
                          > is
                          > > > > there some other possible fault?
                          > > > >
                          > > > > Any ides gratefully received
                          > > > >
                          > > > > TIA
                          > > > >
                          > > > > Norman
                          > > > >
                          > > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                          > wrote:
                          > > > > >
                          > > > > > Hi Norman,
                          > > > > >
                          > > > > > Please check the soldering around T1 and make sure the
                          > > resistor
                          > > > > values are according to the schematic.
                          > > > > >
                          > > > > > 73,
                          > > > > > Tony KB9YIG
                          > > > > > ----- Original Message -----
                          > > > > > From: norman.billingham
                          > > > > > To: softrock40@yahoogroups.com
                          > > > > > Sent: Sunday, November 30, 2008 12:53 PM
                          > > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                          > > > > >
                          > > > > >
                          > > > > > Dear all
                          > > > > >
                          > > > > > Hopefully someone can offer words of help to a non-expert.
                          > > > > >
                          > > > > > I just finished my second softrock, using a V6.0 kit I've
                          > had
                          > > > for
                          > > > > a
                          > > > > > while.
                          > > > > >
                          > > > > > When I inject about 50mV of signal into the antenna at
                          > about
                          > > > > 16kHz
                          > > > > > off centre, I get a beautiful sine wave at both I and Q
                          and
                          > > 90o
                          > > > > phase
                          > > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                          > > only
                          > > > > around
                          > > > > > 50mV.
                          > > > > >
                          > > > > > I followed the detailed instructions and tests on
                          WB5RVZ's
                          > > > great
                          > > > > > pages and all checked out OK except for:
                          > > > > >
                          > > > > > The op-amps. All voltages were OK but the "normal" values
                          > > (both
                          > > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                          > > > bridge
                          > > > > the
                          > > > > > inputs - Robbie's program predicts 3.41V
                          > > > > >
                          > > > > > I measure 500mV at pins 1 and 15 on the mixer where
                          > Robbie's
                          > > > > values
                          > > > > > are 45 mV - looking at the circuit, these pins are both
                          on
                          > an
                          > > > > 1/11K
                          > > > > > potential divider from the 5V rail and 500mV is the
                          > > calculated
                          > > > > value.
                          > > > > >
                          > > > > > I've checked all the component values and soldering
                          around
                          > > the
                          > > > op
                          > > > > > amps and can't find a problem.
                          > > > > >
                          > > > > > Anyone any good ideas please?
                          > > > > >
                          > > > > > Thanks in advance
                          > > > > >
                          > > > > > Norman (M0EBI)
                          > > > > >
                          > > > >
                          > > >
                          > >
                          >




                          --
                          Jose Bonanca  (CT1aos)
                        • Jose Bonanca
                          OK Sorry Tony I have seen the 6241sc8 and it really should do the job. I am sorry for the mistake. 73 ... -- Jose Bonanca (CT1aos)
                          Message 12 of 20 , Dec 1, 2008
                          • 0 Attachment
                            OK
                            Sorry Tony I have seen the 6241sc8 and it really should do the job.
                             
                            I am sorry for the mistake.
                             
                            73


                             
                            On Mon, Dec 1, 2008 at 8:34 PM, Tony Parks <kb9yig@...> wrote:

                            Hi Norman,
                             
                            The TLC6241CS8 should do the job if the op-amp is needing to be replaced.
                             
                            73,
                            Tony KB9YIG
                            ----- Original Message -----
                            Sent: Monday, December 01, 2008 3:05 PM
                            Subject: [softrock40] Re: Troubleshooting Softrock lite RX

                            Thanks Tony.

                            It all checks out visually so I'll take out the capacitors tomorrow
                            and see what happens.

                            I'll probably order up a new U5 just in case. Our local stockist
                            lists 3 versions of the LTC6241, with numbers LTC6241CS8,
                            LTC6241HVCS8 and LTC6241HVIS8. The first two seem to be identical
                            except for a wider temperature range for the second - both are
                            described as type "low noise". The third is decribed as
                            type "CMOS". Does it matter which I get?

                            Norman

                            --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                            >
                            > Hi Norman,
                            >
                            > With DC gain of each op-amp about right, it seems that R9 has a
                            larger resistance than 10 ohms, or C14 has more capacitance than 220
                            pF, or there is an AC load on the pin 1 output of U5. (Also still
                            the possibility there is a problem with U5.) I would suggest
                            removing C16 first to see if the AC voltage at pin 1 of U5 increases
                            with the RF test signal input you are using. Next, remove C14.
                            >
                            > 73,
                            > Tony KB9YIG
                            >
                            > ----- Original Message -----
                            > From: norman.billingham
                            > To: softrock40@yahoogroups.com
                            > Sent: Monday, December 01, 2008 1:27 PM
                            > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                            >
                            >
                            >
                            >
                            > Hi Tony
                            >
                            > There is a fine strong signal on pin 7 and on the output side of
                            the
                            > capacitor. There is no signal at all on pin 1 or on the output
                            lead.
                            >
                            > All measured wrt ground at the screen connection for I and Q
                            lines.
                            >
                            > Only load is the scope probe - at the moment I just have bits of
                            wire
                            > soldered into the I and Q outputs to provide test points before I
                            > mount the board properly in a box and put in the audio cable.
                            >
                            > Thanks for all the help
                            >
                            > 73 Norman
                            >
                            > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                            > >
                            > > Hi Norman,
                            > >
                            > > The DC gain of each of op-amp is about right.
                            > >
                            > > When you checked for the AC I and Q outputs was it at pins 1
                            and 7
                            > of the dual op-amp each with reference to circuit ground or at
                            the
                            > tip and ring connections beyond SMT caps C16 and C17? Also, what
                            > load did you have on the I and Q output lines?
                            > >
                            > > 73,
                            > > Tony KB9YIG
                            > > ----- Original Message -----
                            > > From: norman.billingham
                            > > To: softrock40@yahoogroups.com
                            > > Sent: Monday, December 01, 2008 11:44 AM
                            > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                            > >
                            > >
                            > >
                            > > Hi Tony
                            > >
                            > > pin 1 goes from 2.49 to 3.73V with 10K at pin 2
                            > >
                            > > pin 7 goes from 2.49 to 3.89 with 10K at pin 6
                            > >
                            > > Norman
                            > >
                            > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                            > > >
                            > > > Hi Norman,
                            > > >
                            > > > Please repeat the DC gain test for the dual op-amp. A 10k
                            > resistor
                            > > to ground at pin 2 or pin 6 should result in a voltage change
                            of
                            > 1.25
                            > > volts at pin 1 or pin 7 respectively.
                            > > >
                            > > > 73,
                            > > > Tony KB9YIG
                            > > > ----- Original Message -----
                            > > > From: norman.billingham
                            > > > To: softrock40@yahoogroups.com
                            > > > Sent: Monday, December 01, 2008 10:20 AM
                            > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                            > > >
                            > > >
                            > > > Hi Tony
                            > > >
                            > > > Thanks for coming back so fast
                            > > >
                            > > > This is a 6.0 board so I assume you mean C12 and C13, the two
                            > > 0.047
                            > > > uF decouplers? With my scope AC coupled and on its best
                            > > sensitvity,
                            > > > and 50mV of RF on the input all I can see there (or at pins 7
                            > and
                            > > 9
                            > > > of U4) is about 20 mV of local oscillator frequency. Likewise
                            > at
                            > > > pins 2 and 6 of U5.
                            > > >
                            > > > Pin 1 of U5 is producing nothing and pin 7 has a nice strong
                            Q
                            > > signal
                            > > > at just the right audio frequency.
                            > > >
                            > > > 73
                            > > >
                            > > > Norman
                            > > >
                            > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                            wrote:
                            > > > >
                            > > > > Hi Norman,
                            > > > >
                            > > > > How do the signals look on C11 and C13 with reference to
                            > > circuit
                            > > > ground when you have an RF input to the antenna terminals?
                            > > > >
                            > > > > 73,
                            > > > > Tony KB9YIG
                            > > > > ----- Original Message -----
                            > > > > From: norman.billingham
                            > > > > To: softrock40@yahoogroups.com
                            > > > > Sent: Monday, December 01, 2008 7:32 AM
                            > > > > Subject: [softrock40] Re: Troubleshooting Softrock lite RX
                            > > > >
                            > > > >
                            > > > > Dear Tony
                            > > > >
                            > > > > OK I'm really lost now.
                            > > > >
                            > > > > Carefully checked all component values and soldering of T1
                            > > leads -
                            > > >
                            > > > > all seems OK. Checked all leads and for solder bridges with
                            > > high
                            > > > > magnification and all seems OK.
                            > > > >
                            > > > > With no power and no signal there is continuity between the
                            > two
                            > > > ends
                            > > > > of T1. There is 20 ohms between pins 11 and 12 of U4 and
                            also
                            > > > > between pins 3 and 6.
                            > > > >
                            > > > > There is 774 ohms between CT of T1 and pin 8 of U5, and
                            > > > essentially
                            > > > > zero ohms between CT of T1 and pins 3 and 5 of U5.
                            > > > >
                            > > > > With no power and 1V p/p at 7.1MHz on the antenna there are
                            > > > > symmetrical 450mV signals 180 out of phase at 11/2 and at
                            3/6
                            > > on
                            > > > U4 -
                            > > > > all suggests T1 is OK.
                            > > > >
                            > > > > With power on the board and no signal, there is 5.4V p/p at
                            > > 7.15
                            > > > MHZ
                            > > > > on the two test points on the board - square wave and 90
                            > phase
                            > > > > shifted and these signals are also on pins 2 and 14 of U4.
                            > > > >
                            > > > > With power on and around 50 mV ont he antenna at 7.15 Mhz
                            > there
                            > > > is
                            > > > > about 1V of AF on the Q line and essentially nothing on the
                            I
                            > > > line.
                            > > > >
                            > > > > When I measured the voltahes around U%, all were OK but
                            > > > the "normal"
                            > > > > values (both 2.47V) both went to 4.93 when a 2.6K resistor
                            > was
                            > > > used
                            > > > > to bridge the inputs - Robbie's program predicts 3.41V.
                            > > > >
                            > > > > Is it possible that one channel of U5 just isn't working?
                            or
                            > is
                            > > > > there some other possible fault?
                            > > > >
                            > > > > Any ides gratefully received
                            > > > >
                            > > > > TIA
                            > > > >
                            > > > > Norman
                            > > > >
                            > > > > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@>
                            > wrote:
                            > > > > >
                            > > > > > Hi Norman,
                            > > > > >
                            > > > > > Please check the soldering around T1 and make sure the
                            > > resistor
                            > > > > values are according to the schematic.
                            > > > > >
                            > > > > > 73,
                            > > > > > Tony KB9YIG
                            > > > > > ----- Original Message -----
                            > > > > > From: norman.billingham
                            > > > > > To: softrock40@yahoogroups.com
                            > > > > > Sent: Sunday, November 30, 2008 12:53 PM
                            > > > > > Subject: [softrock40] Troubleshooting Softrock lite RX
                            > > > > >
                            > > > > >
                            > > > > > Dear all
                            > > > > >
                            > > > > > Hopefully someone can offer words of help to a non-expert.
                            > > > > >
                            > > > > > I just finished my second softrock, using a V6.0 kit I've
                            > had
                            > > > for
                            > > > > a
                            > > > > > while.
                            > > > > >
                            > > > > > When I inject about 50mV of signal into the antenna at
                            > about
                            > > > > 16kHz
                            > > > > > off centre, I get a beautiful sine wave at both I and Q
                            and
                            > > 90o
                            > > > > phase
                            > > > > > shift but the p/p voltage on Q is about 3.5 V and on I is
                            > > only
                            > > > > around
                            > > > > > 50mV.
                            > > > > >
                            > > > > > I followed the detailed instructions and tests on
                            WB5RVZ's
                            > > > great
                            > > > > > pages and all checked out OK except for:
                            > > > > >
                            > > > > > The op-amps. All voltages were OK but the "normal" values
                            > > (both
                            > > > > > 2.47V) both went to 4.93 when a 2.6K resistor was used to
                            > > > bridge
                            > > > > the
                            > > > > > inputs - Robbie's program predicts 3.41V
                            > > > > >
                            > > > > > I measure 500mV at pins 1 and 15 on the mixer where
                            > Robbie's
                            > > > > values
                            > > > > > are 45 mV - looking at the circuit, these pins are both
                            on
                            > an
                            > > > > 1/11K
                            > > > > > potential divider from the 5V rail and 500mV is the
                            > > calculated
                            > > > > value.
                            > > > > >
                            > > > > > I've checked all the component values and soldering
                            around
                            > > the
                            > > > op
                            > > > > > amps and can't find a problem.
                            > > > > >
                            > > > > > Anyone any good ideas please?
                            > > > > >
                            > > > > > Thanks in advance
                            > > > > >
                            > > > > > Norman (M0EBI)
                            > > > > >
                            > > > >
                            > > >
                            > >
                            >




                            --
                            Jose Bonanca  (CT1aos)
                          • norman.billingham
                            Hi Tony Checka all capacitor and rseitance values this afternoon and all seemed OK. Despite having inspected everything under 10X magnifcation and found no
                            Message 13 of 20 , Dec 3, 2008
                            • 0 Attachment
                              Hi Tony

                              Checka all capacitor and rseitance values this afternoon and all
                              seemed OK. Despite having inspected everything under 10X
                              magnifcation and found no problems, I decided before yanking
                              components to flux everything around the mixer and op amps and touch
                              up every joint with a hot iron and it came to life - must have been a
                              joint that was OK for DC but not AC as all voltages were OK.

                              It's sitting on the bench putting out about 1.6V of I and Q from
                              about 40mV RF in.

                              Anyway - thanks again for all the help.

                              Any news on when I'm likely to get the Si570 for my V9 kit? Ordered
                              on October 8

                              73 Norman


                              --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                              >
                              > Hi Norman,
                              >
                              > With DC gain of each op-amp about right, it seems that R9 has a
                              larger resistance than 10 ohms, or C14 has more capacitance than 220
                              pF, or there is an AC load on the pin 1 output of U5. (Also still
                              the possibility there is a problem with U5.) I would suggest
                              removing C16 first to see if the AC voltage at pin 1 of U5 increases
                              with the RF test signal input you are using. Next, remove C14.
                              >
                              > 73,
                              > Tony KB9YIG
                              >
                              >
                            • Tony Parks
                              Hi Norman, I have 100 pices of the CMOS Si570 due in later this week or early next week. Your October 8 order would put you in the group to receive one of the
                              Message 14 of 20 , Dec 3, 2008
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                                Hi Norman,
                                 
                                I have 100 pices of the CMOS Si570 due in later this week or early next week.  Your October 8 order would put you in the group to receive one of the Si570 devices to be mailed next Monday or Tuesday.
                                 
                                Glad to hear the I and Q signals now look right with the AC gain about right from antenna input to audio output.
                                 
                                73,
                                Tony KB9YIG
                                ----- Original Message -----
                                Sent: Wednesday, December 03, 2008 1:20 PM
                                Subject: [softrock40] Re: Troubleshooting Softrock lite RX - FIXED!!

                                Hi Tony

                                Checka all capacitor and rseitance values this afternoon and all
                                seemed OK. Despite having inspected everything under 10X
                                magnifcation and found no problems, I decided before yanking
                                components to flux everything around the mixer and op amps and touch
                                up every joint with a hot iron and it came to life - must have been a
                                joint that was OK for DC but not AC as all voltages were OK.

                                It's sitting on the bench putting out about 1.6V of I and Q from
                                about 40mV RF in.

                                Anyway - thanks again for all the help.

                                Any news on when I'm likely to get the Si570 for my V9 kit? Ordered
                                on October 8

                                73 Norman

                                --- In softrock40@yahoogro ups.com, "Tony Parks" <kb9yig@...> wrote:
                                >
                                > Hi Norman,
                                >
                                > With DC gain of each op-amp about right, it seems that R9 has a
                                larger resistance than 10 ohms, or C14 has more capacitance than 220
                                pF, or there is an AC load on the pin 1 output of U5. (Also still
                                the possibility there is a problem with U5.) I would suggest
                                removing C16 first to see if the AC voltage at pin 1 of U5 increases
                                with the RF test signal input you are using. Next, remove C14.
                                >
                                > 73,
                                > Tony KB9YIG
                                >
                                >

                              • norman.billingham
                                Hi Tony Thanks - that s Christmas sorted then! All best Norman ... next week. Your October 8 order would put you in the group to receive one of the Si570
                                Message 15 of 20 , Dec 3, 2008
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                                  Hi Tony

                                  Thanks - that's Christmas sorted then!

                                  All best

                                  Norman

                                  --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@...> wrote:
                                  >
                                  > Hi Norman,
                                  >
                                  > I have 100 pices of the CMOS Si570 due in later this week or early
                                  next week. Your October 8 order would put you in the group to
                                  receive one of the Si570 devices to be mailed next Monday or Tuesday.
                                  >
                                  > Glad to hear the I and Q signals now look right with the AC gain
                                  about right from antenna input to audio output.
                                  >
                                  > 73,
                                  > Tony KB9YIG
                                  > ----- Original Message -----
                                  > From: norman.billingham
                                  > To: softrock40@yahoogroups.com
                                  > Sent: Wednesday, December 03, 2008 1:20 PM
                                  > Subject: [softrock40] Re: Troubleshooting Softrock lite RX -
                                  FIXED!!
                                  >
                                  >
                                  > Hi Tony
                                  >
                                  > Checka all capacitor and rseitance values this afternoon and all
                                  > seemed OK. Despite having inspected everything under 10X
                                  > magnifcation and found no problems, I decided before yanking
                                  > components to flux everything around the mixer and op amps and
                                  touch
                                  > up every joint with a hot iron and it came to life - must have
                                  been a
                                  > joint that was OK for DC but not AC as all voltages were OK.
                                  >
                                  > It's sitting on the bench putting out about 1.6V of I and Q from
                                  > about 40mV RF in.
                                  >
                                  > Anyway - thanks again for all the help.
                                  >
                                  > Any news on when I'm likely to get the Si570 for my V9 kit?
                                  Ordered
                                  > on October 8
                                  >
                                  > 73 Norman
                                  >
                                  > --- In softrock40@yahoogroups.com, "Tony Parks" <kb9yig@> wrote:
                                  > >
                                  > > Hi Norman,
                                  > >
                                  > > With DC gain of each op-amp about right, it seems that R9 has a
                                  > larger resistance than 10 ohms, or C14 has more capacitance than
                                  220
                                  > pF, or there is an AC load on the pin 1 output of U5. (Also still
                                  > the possibility there is a problem with U5.) I would suggest
                                  > removing C16 first to see if the AC voltage at pin 1 of U5
                                  increases
                                  > with the RF test signal input you are using. Next, remove C14.
                                  > >
                                  > > 73,
                                  > > Tony KB9YIG
                                  > >
                                  > >
                                  >
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