Vintage Synth Repair

--- In vintagesynthrepair@yahoogroups.com, "arp2600fan" wrote:
[snip]
> > Now for my question. My 3620 keyboard has always had
> > a problem with erroneous (multiple) triggers. I haven't
> > opened it to look at the mechanics, but many years ago
> > a local tech told me this is a common problem and the
> > fix isn't a big deal. Some keys are worse than others,
> > but four or five are bad enough that spurious triggers
> > occur during normal playing. 
> > 
> > Can anyone tell me what's involved to resolve this
> > problem?
> 
> My guess is to check the keyboard contacts.

Well, I got into the keyboard this weekend and removed all the plastic
key covers to clean them. Now they look great! As for the multiple
triggering problem, this turned out to be dirty contacts (control
voltage contact bus and spring), just as you suggested. Q-tips and
alcohol did the trick. In a few cases, the bus "appeared" to be clean
after the initial cleaning, but required some extra rubbing before the
multi-trigger problem was resolved. Fortunately, none of the contact
springs required adjusting.

On another note, the rubber bushings are seriously deteriorated. This
not only affects the 'feel' of the keyboard but the little "Y" on the
top of the bushing is spread apart, creating drag on the inside walls
of the plastic key covers. This makes many of the keys feel like
they're sticky. I have to use slightly more pressure to begin the down
stroke, and in some case, they drag on the way back up. Fortunately, I
found a source for a set of replacements. If they work as advertised,
the keyboard should feel just like a new!

BTW, I decided to sell my 2600. It may be a few weeks before I get it
ready. Prices on eBay have been out of sight lately. I just can't
justify holding onto it any longer. I'm also going to let go of my two
sequencers (Korg SQ-10 and Sequential Circuits Model 800). Sniff, Sniff.

David