Warning: Zapping can do serious and permanent damage to your organ! If you are considering this procedure, please, please understand exactly what your are doing. I, personally, try to avoid zapping if at all possible. Zapping scares me, and I've also found that it tends to be a temporary cure (particularly if you move your organ very much.) IMHO, if you've got MetallicFuzz in your organ, the proper solution is to open things up and clean it out. (See, for example, HowToRebuildTheVibratoScanner, and the section How to Clean the Percussion Switch Assembly in PercussionTroubleshooting.)
Putting large amounts of current through things like the ToneGenerator pickup coils is almost guaranteed to make them unhappy. Arcing in the key-contacts of your manual is also a bad thing, for obvious reasons.
PleaseAddToThisSection: This section is still under construction.
Probably the safest of juice for zapping is a regular "transistor" nine volt battery. Connect it up so that it drives current through the short you'd like to get rid of, and leave it hooked up for a few seconds. Repeat if neccessary.
Sometimes nine volts is not enough. You can try two batteries in series for eighteen volts (or three batteries, or ...)
Some people suggest using the plate supply voltage B+ to do the zapping. I would suggest you think twice (or more) before resorting to this. If you do try it, keep in mind that HammondsCanKillYou: B+ is a lethal voltage. It is also highly suggested that you use a resistor (10 or 20 kilo-ohms) in series with the B+ to limit the maximum zap current --- this is both to protect your pre-amp's power supply and to prevent arc-welding within whatever it is you're zapping. (Never zap directly from an electrolytic capacitor.)
Remember SmokeIsBad (sparks too!)
OK, just as an addition to this, I have successfully 'zapped' the dendrites from my A-100 a couple of times when I had a 'short' on the 'blue' K wire leading from the AO-28 pre-amp to the percussion switches. I tried the multiple 9v batteries trick without success. What worked for me was using a 12v car battery charger, these normally output a partially rectified voltage so they have a healthy AC element that produces a good 'flash' spark ideal for blowing those dendrites to oblivion. Mine has tapped variable current settings... using the lowest 1 amp (@12v) setting worked. My percussion was working, but no decay... also I had no 25v + voltage on the K terminal when the percussion switch was 'on'. I removed all four wires, blue (K) and the red, brown and green wires adjacent (organ off and unplugged). Earthed the negative side of the battery charger to the AO-28 chassis and zapped each wire in turn for a couple of seconds with the four percussion control switches in all positions. Re-connected the wires... measured the 'K' voltage with the perc switch 'on'... and low and behold I had my 25v + back on the 'K' terminal (dendrites zapped :) ) I then re-adjusted the percussion level cut-off, tried the percussion and all is working 100% again (until the whiskers grow back again). It's a quick and dirty fix... but dragging that percussion control box out for a proper clean is a daunting prospect! DaveH-UK
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