Vintage Synth Repair

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