Vintage Synth Repair

--- In vintagesynthrepair@yahoogroups.com, "windsurfinsusie" <gardens@...> wrote:
>
> Hi, I've just acquired a Roland RS-202. It was described as fully working, but unfortunately it's a little too fully working. I'm not sure if the original owner realised that when you play a note, the bottom F# of the upper half of the split keyboard also gets triggered. It works great in the right key, but not good in others!
> 
> Before I open it up, has anyone got any tips? Am I looking for a duff diode, or a simple short? Can diodes fail as a short circuit? I've found a schematic which seems to imply the problem is with a diode or transistor. What's most likely to fail on these old machines?
> 
> Thanks for any help
> Susie
>
Hi Susie,

Diodes can go short . If you have a simple multimeter , it should have a diode check function. If you have an "old school" meter , put it on 1K ohm range and the diode should read conducting one way and open or non-conducting the other way.

I would check for any ribbon or multipin connectors off the keyboard assby and inspect them and reseat them.

I havent work on one of these yet but there's plenty of time on earth for it.

I have a Minimoog and a Yamaha CS-15 in the shop right now and I also want to play them as well as MOD them for my client.

Cheers,

Scott in Vermont