Zapping dendrites in the vibrato's V/C selector switch

[bnelson218]

I have a C3 with nearly non-existent vibrato and chorus. I've rebuilt a scanner and will change it out for the old one. I also plan to recap the line box (although I doubt that's the culprit), and I'd also like to clean and check the V/C sector switch. Has anyone ever encountered dendrite growth in this switch's contacts, and if so, did you zap it? I'd rather not undo and raise the drawbar rail if I can alternatively send a low DC voltage to the contacts to burn off any growth. Any suggestions are appreciated. Thanks!

[David Anderson]

Dendrite problems in the selector switch assembly are rare, but I have seen them once or twice. You can measure where a short is with an Ohmmeter. Not enough people do this in my estimation.

It's not really that hard to raise the drawbar base and remove this switch. The key is knowing which drawbar assembly screw you have to unscrew to get it loose. Some assemblies are screwed together, and some are clipped. If you are having dendrite problems in there and want the longest-lasting solution, I would thoroughly vacuum inside it with a brush and then spray it out. Otherwise, you may solve one dendrite problem and have another a few months later.

[enor]

If vibrato/chorus is "virtually non existing", I would recap the delay line first! A short means you'll get choppy, exaggerated vibrato, and your problem seems to be the opposite of that

[enor]

That said though, I have indeed seen dendrites in the vibrato selector switch many times. The attached photo is of a customer's organ that I cleanded out the switch on quite recently. The growth I've seen has been on the cover plate (as in the pic), not among the switch leaves. Fine sandpaper solves it much more long term than just zapping; and taking it apart is neither difficult nor a big job.