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Hammond 222222K (Aurora Century) dead on arrival

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  • Hammond 222222K (Aurora Century) dead on arrival

    I already doomed this unit, but wanted to give a last chance for it in case someone here have had and fixed similar issue.

    Shortly said, the organ was almost totally dead, only power switch lamp and leslie motor seemed to work. It soon appeared that -14 volt feed was totally missing from power supply and that was caused by high current draw from motherboard (don't know better name for it, but that's the largest board under another boards). When pulling power connector off from motherboard only, the -14 volt feed is back so there should be no issue in power supply. Obviously there is some kind of short circuit in that board, which takes so much current that it drops voltage down to zero and also rapidly makes power supply heatsink really hot. As said, other boards seem to behave normally and also other voltage feeds from power supply stays where they should be.

    Any ideas if there are particular component(s) on the board that might cause this? As this is my client's unit and it does not have much financial value anyway, I don't want to spend any more hours to fix it...

  • #2
    It's typically a bypass capacitor. Tantalums were used and known to short out over the years. Actually, the function of that part is not really that necessary and if cut, allows the power to come back up and work. They are usually black and barrel shaped with a tapered end. The hardest part of the repair is finding it! Once found, easy to replace.

    Otherwise the keyer IC's "could" be the problem but since they are in sockets, and easy to test by removing them one at a time.

    Good luck!
    Geo

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    • #3
      Thanks Geo! I'll pass this information forward and let owner make his decision. I've been messing with console and spinet TWG Hammonds for years, but this looked like a messy nightmare as soon as I got covers off. Not my cup of tea...

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