Vintage Synth Repair

I just rebuilt a 3604 keyboard.  It definitely sounds like a hold
problem.  Mine had a potted module from Dynamic Measurement
Corporation.  The sounds would fall back immediately on release.  I
never could find any information on the module so I replaced it with
a National LF198A S&H with a 1 uF capacitor.  It really holds the
control voltage now.  Funny thing about that Dynamic Measurement
Corporation module.  There was no gate signal going into it anywhere
so I don't know how the sample function would have ever worked.  I'm
going to try and un-pot it and trace it out someday.  If anyone has
the schematics for the 3604 keyboard I would appreciate a copy. 
Email me off list if you want the information on the circuit.  It
works great.

Dave

--- In vintagesynthrepair@y..., "mfox2011" <mfox@m...> wrote:
> Hello there,
> 
> I bought an Arp2600 two days ago and there seems to be a little 
> problem with the osc-pitch.
> 
> As long as I press a note on the arp's keyboard the tune stays 
> stable. If I release the key, the oscillator pitch tunes down
slowly 
> without stopping. But, if I plug a dummy in the cv keyboard-in on 
> any of osc, the pitch stays stable at 110hz. the keyboard is a 3604 
> model, the arp is version 3.
> 
> Any ideas?
> 
> Another question: the jacks for patching in are 3,6mm instead of
the 
> common 3,5mm. can anybody tell me, where I can get those jacks, 
> preferrably in germany?
> 
> Does anybody know who repairs analogue synthesizers like the arp in 
> germany?
> 
> Thanks in advance.
> 
> Michael