Informational purposes on power supplies. I have a DSK-1 that kept blowing the 1.5A fuse F1. Fuse F2 and the rest were ok. The synth would work fine even with F1 blown. The transformer, inbound AC voltage, and the outbound DC voltage to the main board were normal. Come to find out one of the 5400 diodes was bad and shorted. It allowed power in both directions and would loopback. Power should only flow one way normally (+ to -). Basically F2 was acting for F1 also in this case, so it still worked. After I replaced the one diode, all was ok and F1 no longer blew on power up.