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Re: Divider in Lite II

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  • David, K2MUN
    Hi Bob, Thanks for the reply. Pins 6 and 8 are at 2.47v, which is almost exactly the author s values. I agree that a scope would be nice. I will try to dig
    Message 1 of 6 , Oct 28, 2009
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      Hi Bob,

      Thanks for the reply. Pins 6 and 8 are at 2.47v, which is almost exactly the author's values. I agree that a scope would be nice. I will try to dig up a buddy with one nearby.

      If I had to guess, I'm now thinking that the output of the (working) LO is not actually getting to the divider. I may be able to signal trace the LO signal. Does that make sense? 73, David, K2MUM

      --- In softrock40@yahoogroups.com, "g8voip" <g8voi.reeves59@...> wrote:
      >
      > Hi David,
      >
      > You commented that the voltages on U2 appear correct, apart from the pins 3 and 11 appearing a little low?
      >
      > What voltages do you see on U2 pins 6 and 8? That might give you an indication of what is going on.
      >
      > If they are either at 0V or 5V, then the U2 stage is not working, hence no output at around 4.92MHz.
      >
      > Possibly you might have a short between two adjacent pins, or a pin not soldered to the pad, also check you have the right orientation for the device.
      >
      > The only other thing could possibly be the logic levels of the clock on pins 3 and 11. Trying to measure it with a DVM or analogue meter is rather hit or miss, much better if you have access to an oscilloscope to 'see' what is happening.
      >
      > 73, Bob G8VOI
      >
      >
      >
      >
      > --- In softrock40@yahoogroups.com, "David, K2MUN" <dberkley@> wrote:
      > >
      > > I see no RF output from my SoftRock Lite II K2 IF special. I have been building using WB5RVZ detail build notes and have successfully tested the local oscillator (which is at 19.68 MHz for this special).
      > >
      > > I built the next section, the divider, and all looks visually fine. The voltages on U2 appear okay, although pins 3 and 11 are on the low side of the range (3.58v with a suggested range of 3.5 - 4.5). I hear no output at or around the 4.9 MHz range (where the divider should be running).
      > >
      > > Any suggestions of debugging steps? 73, David, K2MUN
      > >
      >
    • g8voip
      Hi David, With the two output pins from the divider around 2.5v, then they must be active in some way, and therefore LO must be getting to it. If it was not,
      Message 2 of 6 , Oct 29, 2009
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        Hi David,

        With the two output pins from the divider around 2.5v, then they must be active in some way, and therefore LO must be getting to it. If it was not, the outputs from the divider would be static and either be at 0v or 5v.

        Just measuring the voltage of course does not tell you that the waveform is correct, or there is the correct phase shift between the two outputs.

        You would be able to easily see what was happening with a scope, and confirm the divider was working correctly.

        73, Bob G8VOI

        --- In softrock40@yahoogroups.com, "David, K2MUN" <dberkley@...> wrote:
        >
        >
        >
        > Hi Bob,
        >
        > Thanks for the reply. Pins 6 and 8 are at 2.47v, which is almost exactly the author's values. I agree that a scope would be nice. I will try to dig up a buddy with one nearby.
        >
        > If I had to guess, I'm now thinking that the output of the (working) LO is not actually getting to the divider. I may be able to signal trace the LO signal. Does that make sense? 73, David, K2MUM
        >
        > --- In softrock40@yahoogroups.com, "g8voip" <g8voi.reeves59@> wrote:
        > >
        > > Hi David,
        > >
        > > You commented that the voltages on U2 appear correct, apart from the pins 3 and 11 appearing a little low?
        > >
        > > What voltages do you see on U2 pins 6 and 8? That might give you an indication of what is going on.
        > >
        > > If they are either at 0V or 5V, then the U2 stage is not working, hence no output at around 4.92MHz.
        > >
        > > Possibly you might have a short between two adjacent pins, or a pin not soldered to the pad, also check you have the right orientation for the device.
        > >
        > > The only other thing could possibly be the logic levels of the clock on pins 3 and 11. Trying to measure it with a DVM or analogue meter is rather hit or miss, much better if you have access to an oscilloscope to 'see' what is happening.
        > >
        > > 73, Bob G8VOI
        > >
        > >
        > >
        > >
        > > --- In softrock40@yahoogroups.com, "David, K2MUN" <dberkley@> wrote:
        > > >
        > > > I see no RF output from my SoftRock Lite II K2 IF special. I have been building using WB5RVZ detail build notes and have successfully tested the local oscillator (which is at 19.68 MHz for this special).
        > > >
        > > > I built the next section, the divider, and all looks visually fine. The voltages on U2 appear okay, although pins 3 and 11 are on the low side of the range (3.58v with a suggested range of 3.5 - 4.5). I hear no output at or around the 4.9 MHz range (where the divider should be running).
        > > >
        > > > Any suggestions of debugging steps? 73, David, K2MUN
        > > >
        > >
        >
      • Alan
        ... From: David, K2MUN Subject: [softrock40] Divider in Lite II ... This means pins 6 & 8 are around 2V5? If so, it should be clocking and you need to look
        Message 3 of 6 , Oct 29, 2009
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          ----- Original Message -----
          From: "David, K2MUN"
          Subject: [softrock40] Divider in Lite II


          >
          > I built the next section, the divider, and all looks visually fine. The
          > voltages on U2 appear okay,

          This means pins 6 & 8 are around 2V5?

          If so, it should be clocking and you need to look more carefully for the
          divided signal.
          Just put an antenna wire close to it, I don't think you really need a scope,
          although it might help.

          73 Alan G4ZFQ
        • David, K2MUN
          Thanks to Bob and Alan, kind souls who pointed out that the divider must be clocking. It s embarrassing, but I learned that one shouldn t try using a K2 to
          Message 4 of 6 , Oct 29, 2009
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            Thanks to Bob and Alan, kind souls who pointed out that the divider must be clocking. It's embarrassing, but I learned that one shouldn't try using a K2 to listen near its IF frequency, it is totally deaf. Another receiver immediately showed that the divider is working fine.

            Now on to the next learning experience! Thanks again. 73, David, K2MUN

            --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
            >
            >
            > ----- Original Message -----
            > From: "David, K2MUN"
            > Subject: [softrock40] Divider in Lite II
            >
            >
            > >
            > > I built the next section, the divider, and all looks visually fine. The
            > > voltages on U2 appear okay,
            >
            > This means pins 6 & 8 are around 2V5?
            >
            > If so, it should be clocking and you need to look more carefully for the
            > divided signal.
            > Just put an antenna wire close to it, I don't think you really need a scope,
            > although it might help.
            >
            > 73 Alan G4ZFQ
            >
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