Vintage Synth Repair

I don't know this unit, but I think they are probably
just common signal diodes like 1n4148 or 1n914.
If it's not the wiring/solder/diodes, it could be the
chip that is either driving the keyboard scan lines
or the chip that is reading them.  You'll have to 
follow the traces to find the offender...

-----Original Message-----
>From: Antoine Deschênes <antdes45@...>
>Sent: Jan 26, 2006 7:20 AM
>To: vintagesynthrepair@yahoogroups.com
>Subject: [vintagesynthrepair] Roland RD-300S trouble
>
>Hi,
>
>Someone asked me to fix a Roland RD-300S(7 notes not working). I managed 
>to open it and remove the keys. Now, the only problem is that there is 
>some rust on the solders, but the contact looks OK(After cleanup). I'll 
>re-work the solder points tomorrow, but I'd like to know the diode type 
>in case that one of them is dead.
>
>--
>Antoine