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Farfisa Compact Duo - decent board photos?

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  • Farfisa Compact Duo - decent board photos?

    Ok, so I really screwed something up. I was replacing caps, and things were slowly improving. And then...I got cocky, and did a bunch of work without powering up to test. I probably reversed the polarity of one or more caps, but I'm not sure. I'm poring over the schematic to figure it out, but I'm struggling to find the cause of the issue. The lights don't come on, and the sound just buzzes with no tones.

    Does anyone have access to a mk2 compact duo that would be willing to photograph the boards for me? I think comparing the caps visually will help track down my problem.

    The f/ar is working normally.

    Thank you!

  • #2
    I haven’t got time to open mine up but Google Farfisa Compact Duo Flickr and a guy called Michael has heavily photographed a restoration of a Compact Duo- every board. Good luck!
    Hammond A100, M102, XB3, XB5, X5, TTR-100
    Lowrey Heritage DSO-1, H25-3, Yamaha E70
    Farfisa Compact Duo Mk2, Vox Continental 300, Korg BX3 Mk1, Leslie 122, 145, 910
    www.drawbardave.co.uk

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    • #3
      Here ya go . . .

      https://www.flickr.com/photos/transa...57631546361149

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      • #4
        One of the most common errors you find on schematics is having the +/- polarity of electrolytic capacitors drawn backwards, and there are at least a couple of examples of this on Farfisa schematics. Always do a reality check and/or mark the polarity of parts before removing them.

        In other words, the polarity will be correct on the board, but reversed on the schematic. I even found this once on a McIntosh schemo.
        I'm David. 'Dave' is someone else's name.

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        • #5
          This is very helpful. Thanks, all!

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          • #6
            Have you checked for 9vdc on the boards? You will need the schematics for the terminal number. If I remember correctly there is a 9 volt dc to the boards and then 9 volts ac to the bulbs including the tremolo bulb. I haven’t had mine open for three years so not 100 percent confident.
            Hammond A100, M102, XB3, XB5, X5, TTR-100
            Lowrey Heritage DSO-1, H25-3, Yamaha E70
            Farfisa Compact Duo Mk2, Vox Continental 300, Korg BX3 Mk1, Leslie 122, 145, 910
            www.drawbardave.co.uk

            Comment


            • #7
              I am working on bringing back the tremolo and I took a photograph of PA-27 with back and front pics of the board in order to make testing/comparison easy. I so far have replaced the 6V .05a bulb (took two months to get it because it was not in stock) from www.easy-lightbulbs.com ... and now I am ordering caps on this board and caps for other boards related to PA-27. Everything else I believe works fine, some funk with some notes but will dive into that later. Any discoveries I will report back.. testing for now why I am not getting some correct voltages on the test points 5-8 (I labeled TP1-8 on the schematic) . As for the capacitor on PA-27 200uf 25WV ... I can't actually tell the polarity of it but will double check when I take it out.

              Click image for larger version

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              • #8
                Check you have the correct bulb in your expression pedal as well. Mine was wrong when I restored my MKII Duo and it played havoc with the tremolo bulb IIRC. A complete recap of the organ and key contact cleaning fixed all my other woes/missing tones.
                Hammond A100, M102, XB3, XB5, X5, TTR-100
                Lowrey Heritage DSO-1, H25-3, Yamaha E70
                Farfisa Compact Duo Mk2, Vox Continental 300, Korg BX3 Mk1, Leslie 122, 145, 910
                www.drawbardave.co.uk

                Comment


                • #9
                  Thanks for sharing the photos. Very useful in my research of what all of the controls do. :-)

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