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Re: Troubleshooting Softrock lite RX

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  • 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 1 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 2 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 3 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 4 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 5 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 6 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 7 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 8 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 9 of 20 , Dec 3, 2008
                    • 0 Attachment
                      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 10 of 20 , Dec 3, 2008
                      • 0 Attachment
                        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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