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Puzzled by Oscillator in 455khz Softrock Lite 6.2

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  • Andrew
    I am finally building up the 455khz Softrock Lite 6.2 I ordered a while back. The kit has a 1.843MHZ crystal and uses divide by 4 so is a little different to
    Message 1 of 7 , May 28 2:50 AM
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      I am finally building up the 455khz Softrock Lite 6.2 I ordered a while back.

      The kit has a 1.843MHZ crystal and uses divide by 4 so is a little different to other descriptions I have seen of 45x IF softrocks.

      I can't make sense of the Q2 collector output.

      The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx 4.5v with a 1v peak to peak sine wave.

      In the divide by 4 configuration the collector is taken directly to the CLK on 74HC74 so I would have expected the collector voltage to average around 2.5v with sufficient swing to clock the 74HC74.

      I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with no jumper installed... I removed to it check that it wasn't a bad IC loading it up.

      R7 is 449 ohms. Everything looks right according to the diagrams...

      Thanks in advance for any suggestions.

      Andrew ZL1WJQ
    • Alan
      ... From: Andrew Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2 ... Softrock Lite II. In this oscillator design I have found
      Message 2 of 7 , May 28 3:37 AM
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        ----- Original Message -----
        From: "Andrew"
        Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2


        >I am finally building up the 455khz Softrock Lite 6.2 I ordered a while
        >back.
        >

        Softrock Lite II. In this oscillator design I have found adjusting R16 is
        sometimes necessary. If the DC voltage on Q2 collector is low try
        increasing, or even removing it. The main thing is that U2 clocks reliably.

        73 Alan G4ZFQ




        > The kit has a 1.843MHZ crystal and uses divide by 4 so is a little
        > different to other descriptions I have seen of 45x IF softrocks.
        >
        > I can't make sense of the Q2 collector output.
        >
        > The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx
        > 4.5v with a 1v peak to peak sine wave.
        >
        > In the divide by 4 configuration the collector is taken directly to the
        > CLK on 74HC74 so I would have expected the collector voltage to average
        > around 2.5v with sufficient swing to clock the 74HC74.
        >
        > I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with no
        > jumper installed... I removed to it check that it wasn't a bad IC loading
        > it up.
        >
        > R7 is 449 ohms. Everything looks right according to the diagrams...
        >
        > Thanks in advance for any suggestions.
        >
        > Andrew ZL1WJQ
        >
        >
        >
        > ------------------------------------
        >
        > Yahoo! Groups Links
        >
        >
        >
      • Andrew
        Thanks Alan... I will give that I try. I checked the SoftRock Lite II schematic and R16 there is the equivalent of R6 in the 6.2... it is 22.1k on my board and
        Message 3 of 7 , May 28 3:49 AM
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          Thanks Alan... I will give that I try.

          I checked the SoftRock Lite II schematic and R16 there is the equivalent of R6 in the 6.2... it is 22.1k on my board and is one of the parts that were listed as specific to 455khz IF use.

          Will adjust the values and see what effect it has.

          Regards

          Andrew ZL1WJQ


          --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
          >
          >
          > ----- Original Message -----
          > From: "Andrew"
          > Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2
          >
          >
          > >I am finally building up the 455khz Softrock Lite 6.2 I ordered a while
          > >back.
          > >
          >
          > Softrock Lite II. In this oscillator design I have found adjusting R16 is
          > sometimes necessary. If the DC voltage on Q2 collector is low try
          > increasing, or even removing it. The main thing is that U2 clocks reliably.
          >
          > 73 Alan G4ZFQ
          >
          >
          >
          >
          > > The kit has a 1.843MHZ crystal and uses divide by 4 so is a little
          > > different to other descriptions I have seen of 45x IF softrocks.
          > >
          > > I can't make sense of the Q2 collector output.
          > >
          > > The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx
          > > 4.5v with a 1v peak to peak sine wave.
          > >
          > > In the divide by 4 configuration the collector is taken directly to the
          > > CLK on 74HC74 so I would have expected the collector voltage to average
          > > around 2.5v with sufficient swing to clock the 74HC74.
          > >
          > > I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with no
          > > jumper installed... I removed to it check that it wasn't a bad IC loading
          > > it up.
          > >
          > > R7 is 449 ohms. Everything looks right according to the diagrams...
          > >
          > > Thanks in advance for any suggestions.
          > >
          > > Andrew ZL1WJQ
          > >
          > >
          > >
          > > ------------------------------------
          > >
          > > Yahoo! Groups Links
          > >
          > >
          > >
          >
        • aa9wqham@aol.com
          Change R16 22.1 or it s equivalent to a 10k and it should work just fine. Larry W9AMR In a message dated 5/28/2010 6:53:46 A.M. Eastern Daylight Time,
          Message 4 of 7 , May 28 11:20 AM
          • 0 Attachment
            Change R16 22.1 or it's equivalent to a 10k and it should work just fine.
             
            Larry W9AMR
             
            In a message dated 5/28/2010 6:53:46 A.M. Eastern Daylight Time, jaquinn@... writes:
             

            Thanks Alan... I will give that I try.

            I checked the SoftRock Lite II schematic and R16 there is the equivalent of R6 in the 6.2... it is 22.1k on my board and is one of the parts that were listed as specific to 455khz IF use.

            Will adjust the values and see what effect it has.

            Regards

            Andrew ZL1WJQ

            --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
            >
            >
            > ----- Original Message -----
            > From: "Andrew"
            > Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2
            >
            >
            > >I am finally building up the 455khz Softrock Lite 6.2 I ordered a while
            > >back.
            > >
            >
            > Softrock Lite II. In this oscillator design I have found adjusting R16 is
            > sometimes necessary. If the DC voltage on Q2 collector is low try
            > increasing, or even removing it. The main thing is that U2 clocks reliably.
            >
            > 73 Alan G4ZFQ
            >
            >
            >
            >
            > > The kit has a 1.843MHZ crystal and uses divide by 4 so is a little
            > > different to other descriptions I have seen of 45x IF softrocks.
            > >
            > > I can't make sense of the Q2 collector output.
            > >
            > > The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx
            > > 4.5v with a 1v peak to peak sine wave.
            > >
            > > In the divide by 4 configuration the collector is taken directly to the
            > > CLK on 74HC74 so I would have expected the collector voltage to average
            > > around 2.5v with sufficient swing to clock the 74HC74.
            > >
            > > I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with no
            > > jumper installed... I removed to it check that it wasn't a bad IC loading
            > > it up.
            > >
            > > R7 is 449 ohms. Everything looks right according to the diagrams...
            > >
            > > Thanks in advance for any suggestions.
            > >
            > > Andrew ZL1WJQ
            > >
            > >
            > >
            > > ------------------------------------
            > >
            > > Yahoo! Groups Links
            > >
            > >
            > >
            >

          • Alan
            ... From: Subject: Re: [softrock40] Re: Puzzled by Oscillator in 455khz Softrock Lite 6.2 ... Yes, I got that the wrong way round! It needs
            Message 5 of 7 , May 28 1:53 PM
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              ----- Original Message -----
              From: <aa9wqham@...>
              Subject: Re: [softrock40] Re: Puzzled by Oscillator in 455khz Softrock Lite
              6.2


              >Change R16 22.1 or it's equivalent to a 10k and it should work just fine.

              >Larry W9AMR

              Yes, I got that the wrong way round! It needs reducing.

              73 Alan G4ZFQ


              >In a message dated 5/28/2010 6:53:46 A.M. Eastern Daylight Time,
              jaquinn@... writes:




              Thanks Alan... I will give that I try.

              I checked the SoftRock Lite II schematic and R16 there is the equivalent
              of R6 in the 6.2... it is 22.1k on my board and is one of the parts that
              were listed as specific to 455khz IF use.

              Will adjust the values and see what effect it has.

              Regards

              Andrew ZL1WJQ

              --- In _softrock40@yahoogroups.com_ (mailto:softrock40@yahoogroups.com) ,
              "Alan" <alan4alan@...> wrote:
              >
              >
              > ----- Original Message -----
              > From: "Andrew"
              > Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2
              >
              >
              > >I am finally building up the 455khz Softrock Lite 6.2 I ordered a while
              > >back.
              > >
              >
              > Softrock Lite II. In this oscillator design I have found adjusting R16
              is
              > sometimes necessary. If the DC voltage on Q2 collector is low try
              > increasing, or even removing it. The main thing is that U2 clocks
              reliably.
              >
              > 73 Alan G4ZFQ
              >
              >
              >
              >
              > > The kit has a 1.843MHZ crystal and uses divide by 4 so is a little
              > > different to other descriptions I have seen of 45x IF softrocks.
              > >
              > > I can't make sense of the Q2 collector output.
              > >
              > > The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx
              > > 4.5v with a 1v peak to peak sine wave.
              > >
              > > In the divide by 4 configuration the collector is taken directly to
              the
              > > CLK on 74HC74 so I would have expected the collector voltage to
              average
              > > around 2.5v with sufficient swing to clock the 74HC74.
              > >
              > > I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with
              no
              > > jumper installed... I removed to it check that it wasn't a bad IC
              loading
              > > it up.
              > >
              > > R7 is 449 ohms. Everything looks right according to the diagrams...
              > >
              > > Thanks in advance for any suggestions.
              > >
              > > Andrew ZL1WJQ
              > >
              > >
              > >
              > > ------------------------------------
              > >
              > > Yahoo! Groups Links
              > >
              > >
              > >
              >
            • Andrew
              Thanks guys... 10k worked well and I am seeing a good output on the collector now. Sorry to ask... looking at the various other posts there are several places
              Message 6 of 7 , May 28 2:49 PM
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                Thanks guys... 10k worked well and I am seeing a good output on the collector now.

                Sorry to ask... looking at the various other posts there are several places where this was answered and they referred to R16 but I didn't realize that R16 on the 6.2 and II are different.... R16 in the 6.2 is already 10K and in the OE enable circuit.

                Regards

                Andrew ZL1WJQ

                --- In softrock40@yahoogroups.com, aa9wqham@... wrote:
                >
                > Change R16 22.1 or it's equivalent to a 10k and it should work just fine.
                >
                > Larry W9AMR
                >
                >
                > In a message dated 5/28/2010 6:53:46 A.M. Eastern Daylight Time,
                > jaquinn@... writes:
                >
                >
                >
                >
                > Thanks Alan... I will give that I try.
                >
                > I checked the SoftRock Lite II schematic and R16 there is the equivalent
                > of R6 in the 6.2... it is 22.1k on my board and is one of the parts that
                > were listed as specific to 455khz IF use.
                >
                > Will adjust the values and see what effect it has.
                >
                > Regards
                >
                > Andrew ZL1WJQ
                >
                > --- In _softrock40@yahoogroups.com_ (mailto:softrock40@yahoogroups.com) ,
                > "Alan" <alan4alan@> wrote:
                > >
                > >
                > > ----- Original Message -----
                > > From: "Andrew"
                > > Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2
                > >
                > >
                > > >I am finally building up the 455khz Softrock Lite 6.2 I ordered a while
                > > >back.
                > > >
                > >
                > > Softrock Lite II. In this oscillator design I have found adjusting R16
                > is
                > > sometimes necessary. If the DC voltage on Q2 collector is low try
                > > increasing, or even removing it. The main thing is that U2 clocks
                > reliably.
                > >
                > > 73 Alan G4ZFQ
                > >
                > >
                > >
                > >
                > > > The kit has a 1.843MHZ crystal and uses divide by 4 so is a little
                > > > different to other descriptions I have seen of 45x IF softrocks.
                > > >
                > > > I can't make sense of the Q2 collector output.
                > > >
                > > > The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx
                > > > 4.5v with a 1v peak to peak sine wave.
                > > >
                > > > In the divide by 4 configuration the collector is taken directly to
                > the
                > > > CLK on 74HC74 so I would have expected the collector voltage to
                > average
                > > > around 2.5v with sufficient swing to clock the 74HC74.
                > > >
                > > > I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with
                > no
                > > > jumper installed... I removed to it check that it wasn't a bad IC
                > loading
                > > > it up.
                > > >
                > > > R7 is 449 ohms. Everything looks right according to the diagrams...
                > > >
                > > > Thanks in advance for any suggestions.
                > > >
                > > > Andrew ZL1WJQ
                > > >
                > > >
                > > >
                > > > ------------------------------------
                > > >
                > > > Yahoo! Groups Links
                > > >
                > > >
                > > >
                > >
                >
              • aa9wqham@aol.com
                On the 6.2 the equal to R16 is R6. Larry W9AMR In a message dated 5/28/2010 6:01:02 P.M. Eastern Daylight Time, jaquinn@ihug.co.nz writes: Thanks guys... 10k
                Message 7 of 7 , May 28 3:58 PM
                • 0 Attachment
                  On the 6.2 the equal to R16 is R6.
                   
                  Larry W9AMR
                   
                  In a message dated 5/28/2010 6:01:02 P.M. Eastern Daylight Time, jaquinn@... writes:
                   

                  Thanks guys... 10k worked well and I am seeing a good output on the collector now.

                  Sorry to ask... looking at the various other posts there are several places where this was answered and they referred to R16 but I didn't realize that R16 on the 6.2 and II are different.... R16 in the 6.2 is already 10K and in the OE enable circuit.

                  Regards

                  Andrew ZL1WJQ

                  --- In softrock40@yahoogroups.com, aa9wqham@... wrote:
                  >
                  > Change R16 22.1 or it's equivalent to a 10k and it should work just fine.
                  >
                  > Larry W9AMR
                  >
                  >
                  > In a message dated 5/28/2010 6:53:46 A.M. Eastern Daylight Time,
                  > jaquinn@... writes:
                  >
                  >
                  >
                  >
                  > Thanks Alan... I will give that I try.
                  >
                  > I checked the SoftRock Lite II schematic and R16 there is the equivalent
                  > of R6 in the 6.2... it is 22.1k on my board and is one of the parts that
                  > were listed as specific to 455khz IF use.
                  >
                  > Will adjust the values and see what effect it has.
                  >
                  > Regards
                  >
                  > Andrew ZL1WJQ
                  >
                  > --- In _softrock40@yahoogroups.com_ (mailto:softrock40@yahoogroups.com) ,
                  > "Alan" <alan4alan@> wrote:
                  > >
                  > >
                  > > ----- Original Message -----
                  > > From: "Andrew"
                  > > Subject: [softrock40] Puzzled by Oscillator in 455khz Softrock Lite 6.2
                  > >
                  > >
                  > > >I am finally building up the 455khz Softrock Lite 6.2 I ordered a while
                  > > >back.
                  > > >
                  > >
                  > > Softrock Lite II. In this oscillator design I have found adjusting R16
                  > is
                  > > sometimes necessary. If the DC voltage on Q2 collector is low try
                  > > increasing, or even removing it. The main thing is that U2 clocks
                  > reliably.
                  > >
                  > > 73 Alan G4ZFQ
                  > >
                  > >
                  > >
                  > >
                  > > > The kit has a 1.843MHZ crystal and uses divide by 4 so is a little
                  > > > different to other descriptions I have seen of 45x IF softrocks.
                  > > >
                  > > > I can't make sense of the Q2 collector output.
                  > > >
                  > > > The oscillator runs fine at 1.843MHZ... input at the Q2 base is approx
                  > > > 4.5v with a 1v peak to peak sine wave.
                  > > >
                  > > > In the divide by 4 configuration the collector is taken directly to
                  > the
                  > > > CLK on 74HC74 so I would have expected the collector voltage to
                  > average
                  > > > around 2.5v with sufficient swing to clock the 74HC74.
                  > > >
                  > > > I am seeing an 0.5v peak to peak signal at approx 0.25v. This is with
                  > no
                  > > > jumper installed... I removed to it check that it wasn't a bad IC
                  > loading
                  > > > it up.
                  > > >
                  > > > R7 is 449 ohms. Everything looks right according to the diagrams...
                  > > >
                  > > > Thanks in advance for any suggestions.
                  > > >
                  > > > Andrew ZL1WJQ
                  > > >
                  > > >
                  > > >
                  > > > ------------------------------------
                  > > >
                  > > > Yahoo! Groups Links
                  > > >
                  > > >
                  > > >
                  > >
                  >

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