Vintage Synth Repair

Hi, Jim,

I've got also ProDGX, fortunately without problems. I can't help with  
your problem, so have just one question: do you have Service  
Documentation? This I can send to you.

I'd start with power supply check, then cleaning and reseating  
connectors, re-seat IC's in sockets, check PCB tracks, calibrate  
everything as written in SM... usual staff. Then check keyboard  
circuits, ROMs... Recapping can help, too, at least electrolytic  
capacitors.

Daniel Forro


On 17 Dec, 2012, at 6:03 PM, Jim Blair wrote:

> Hello!
>
> Here's an odd one up for discussion. I have a Arp ProDGX. Everything
> works fine....except.....if I hit the top key (highest note) it
> briefly plays the note, then very quickly drops down to a much lower
> note (almost instantaneously). After this little event, every key
> stops working, other than a click for each note.
>
> This happens on every patch.
>
> Then, if I turn the power off, then back on, everything is fine again
> until the next time I hit that highest note.
>
> Any suggestions on where to point my screwdriver and multimeter?
>
>
> Thanks,
>
> Jim Blair
> Ape Island Sound
> http://www.facebook.com/ApeIslandSound