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Re: [softrock40] RX ensemble II No output at completion of Local Oscillator and Control section

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  • Alan
    ... Subject: [softrock40] RX ensemble II No output at completion of Local Oscillator and Control section ... Kevin So CFGSR Test tab shows no error when you
    Message 1 of 7 , Dec 12, 2012
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      ----- Original Message -----
      Subject: [softrock40] RX ensemble II No output at completion of Local Oscillator and Control section


      >which recognized the SI 570, and allows proper frequency as well as proper control of the frequency.

      Kevin

      So CFGSR Test tab shows no error when you click "Get"?

      >The problem is that I have no LO output with either my Startek frequency counter, or a very sensitive receiver.
      >

      You are checking at the actual output frequency, not the tune frequency?

      What voltage at the output pad of the Si570?
      No short to ground?
      Are you sure the Si570 is soldered properly? This is a very common problem.

      73 Alan G4ZFQ
    • wa2isc
      ... Thanks for the reply, Alan. I checked both the set frequency and the requested frequency just in case. Clicking get shows no reaction, and no error
      Message 2 of 7 , Dec 12, 2012
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        --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
        >
        >
        > ----- Original Message -----
        > Subject: [softrock40] RX ensemble II No output at completion of Local Oscillator and Control section
        >
        >
        > >which recognized the SI 570, and allows proper frequency as well as proper control of the frequency.
        >
        > Kevin
        >
        > So CFGSR Test tab shows no error when you click "Get"?
        >
        > >The problem is that I have no LO output with either my Startek frequency counter, or a very sensitive receiver.
        > >
        >
        > You are checking at the actual output frequency, not the tune frequency?
        >
        > What voltage at the output pad of the Si570?
        > No short to ground?
        > Are you sure the Si570 is soldered properly? This is a very common problem.
        >
        > 73 Alan G4ZFQ


        Thanks for the reply, Alan. I checked both the set frequency and the "requested frequency" just in case. Clicking "get" shows no reaction, and no error message. I don't know what that means, but there is no error shown.

        The output on the SI570 shows 1.66 V at 60 Hz and no appearant short to ground. As mentioned, I'm no expert on SMDs, but my jewelers loop tells me that the solder is OK on all 8 pins (ie, no solder bridges or missed pads. It there a way to test the Si570 in situ?

        73, Kevin
      • Alan
        ... Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section ... Kevin What do you mean 60Hz? About 1V5 DC is
        Message 3 of 7 , Dec 13, 2012
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          ----- Original Message -----
          Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section




          >
          > The output on the SI570 shows 1.66 V at 60 Hz and no appearant short to ground.

          Kevin

          What do you mean 60Hz?
          About 1V5 DC is expected. And there should be RF, 3V pk-pk.
          Have you grounded your instruments to USB ground?

          > jewelers loop tells me that the solder is OK on all 8 pins (ie, no solder bridges or missed pads. It there a way to test the
          Si570 in situ?

          You almost have. It should have an output if it has power.
          Check voltage on pad 2.
          Normally 3V, unused but if it is grounded in some way it stops the output.

          73 Alan G4ZFQ
        • wa2isc
          ... Hi, again Alan, I don t have ready access to a scope, so I use a conbination of the Freq. counter and the Fluke. Since I was looking for AC (OK, RF), I
          Message 4 of 7 , Dec 13, 2012
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            --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
            >
            >
            > ----- Original Message -----
            > Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section
            >
            >
            >
            >
            > >
            > > The output on the SI570 shows 1.66 V at 60 Hz and no appearant short to ground.
            >
            > Kevin
            >
            > What do you mean 60Hz?
            > About 1V5 DC is expected. And there should be RF, 3V pk-pk.
            > Have you grounded your instruments to USB ground?
            >
            > > jewelers loop tells me that the solder is OK on all 8 pins (ie, no solder bridges or missed pads. It there a way to test the
            > Si570 in situ?
            >
            > You almost have. It should have an output if it has power.
            > Check voltage on pad 2.
            > Normally 3V, unused but if it is grounded in some way it stops the output.
            >
            > 73 Alan G4ZFQ
            >
            Hi, again Alan,

            I don't have ready access to a 'scope, so I use a conbination of the Freq. counter and the Fluke. Since I was looking for AC (OK, RF), I got the 60 Hz on the circuit. I didn't look at the DC voltage. Now, I show .95 VDC on pad 4, and 0 on pad 2. Pad 2 shows infinite R, so not grounded.

            Yes, I used the USB ground for these measurements. I am lost!

            Thanks for your sage advice
          • Alan
            ... Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section ... Strange, pad 2 should be about 3V. It has an
            Message 5 of 7 , Dec 13, 2012
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              ----- Original Message -----
              Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section


              > 0 on pad 2. Pad 2 shows infinite R, so not grounded.
              >

              Strange, pad 2 should be about 3V. It has an internal pull-up. When grounded it stops the output. But it is normally left
              unconnected.
              If it is definitely soldered to the Si570 then the Si570 is faulty.
              That is assuming the Test tab of CFGSR is still showing no error when Get is clicked. No error means the Si570 is talking properly
              to the AVR controller.

              73 Alan G4ZFQ
            • wa2isc
              Alan, Thanks for all the help. My conclusion was that the Si 570 was bad, but as i said, I am a newbie to this whole SDR. Pad 2 is definately showing no
              Message 6 of 7 , Dec 13, 2012
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                Alan,

                Thanks for all the help. My conclusion was that the Si 570 was bad, but as i said, I am a newbie to this whole SDR. Pad 2 is definately showing no voltage, and the test does not return an error. You have confirmed to me that it is the Si 570. I will attempt to replace it ( I have nightmares about desoldering it, but...). Again, thanks for the help.

                73, Kevin

                --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                >
                >
                > ----- Original Message -----
                > Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section
                >
                >
                > > 0 on pad 2. Pad 2 shows infinite R, so not grounded.
                > >
                >
                > Strange, pad 2 should be about 3V. It has an internal pull-up. When grounded it stops the output. But it is normally left
                > unconnected.
                > If it is definitely soldered to the Si570 then the Si570 is faulty.
                > That is assuming the Test tab of CFGSR is still showing no error when Get is clicked. No error means the Si570 is talking properly
                > to the AVR controller.
                >
                > 73 Alan G4ZFQ
                >
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