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Re: [softrock40] Re: I think I found my so-called bad chip problem.

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  • John
    Use a toothbrush and Isopropyl alcohol and the pcb will look like it just left the factory. John G3UGY From: wfahle Sent: Saturday, November 03, 2012 9:50 PM
    Message 1 of 9 , Nov 4, 2012
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      Use a toothbrush and Isopropyl alcohol and the pcb will look like it just left the factory.
       
      John G3UGY
       

      From: wfahle
      Sent: Saturday, November 03, 2012 9:50 PM
      Subject: [softrock40] Re: I think I found my so-called bad chip problem.

       

      No offense taken; it's my first PCB. I did try rubbing alchohol but it made more of a mess. The whole board is a mess, but especially this part after all the diagnosis I went through to find the fault, including destroying a chip and soldering green wire onto it, etc. It will be a miracle if it works.

    • William Fahle
      Yes, I wish I had been more patient in trying things before starting to unsolder. In particular the solution came from continuity testing with the ohms turned
      Message 2 of 9 , Nov 5, 2012
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        Yes, I wish I had been more patient in trying things before starting
        to unsolder. In particular the solution came from continuity testing
        with the ohms turned up to 200k. This allowed me to see that certain
        circuits were not open, but were in fact 21k, which led to the
        diagnosis. In any case, I learned a lot doing this, so no regrets.

        So far it passes every test; I now discover I need a second soundcard
        to actually use the transmit. Also my primary soundcard is mono in, so
        it is useless as a receiver card, so while I get semi-readable signals
        from a backyard dipole, I'm not 100% sure what the receiver
        performance will be yet, as there are too many variables. A quickly
        thrown-up antenna, a bad soundcard, a new softrock build with problems
        along the way (and no scope to check the output), default calibration,
        all conspire to give me a big screen full of white noise with the
        occasional discernable cw signal, and muddy signals that I can only
        assume are ssb. I'm going to get a USB soundcard for the receiver side
        and use the built-in for transmit and then report back. The built-in
        definitely puts out stereo, so that shouldn't be an issue for
        transmit.
      • pond.james_pond
        You re not alone. Took me several days of frustrated reworking before finding the etch failure. I felt less charitable than yourself at the time.
        Message 3 of 9 , Nov 5, 2012
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          You're not alone. Took me several days of frustrated reworking before finding the etch failure. I felt less charitable than yourself at the time.

          --- In softrock40@yahoogroups.com, William Fahle <billfahle@...> wrote:
          >
          > Yes, I wish I had been more patient in trying things before starting
          > to unsolder. In particular the solution came from continuity testing
          > with the ohms turned up to 200k. This allowed me to see that certain
          > circuits were not open, but were in fact 21k, which led to the
          > diagnosis. In any case, I learned a lot doing this, so no regrets.
          >
          > So far it passes every test; I now discover I need a second soundcard
          > to actually use the transmit. Also my primary soundcard is mono in, so
          > it is useless as a receiver card, so while I get semi-readable signals
          > from a backyard dipole, I'm not 100% sure what the receiver
          > performance will be yet, as there are too many variables. A quickly
          > thrown-up antenna, a bad soundcard, a new softrock build with problems
          > along the way (and no scope to check the output), default calibration,
          > all conspire to give me a big screen full of white noise with the
          > occasional discernable cw signal, and muddy signals that I can only
          > assume are ssb. I'm going to get a USB soundcard for the receiver side
          > and use the built-in for transmit and then report back. The built-in
          > definitely puts out stereo, so that shouldn't be an issue for
          > transmit.
          >
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