seems this thread may just help me out..
i have a EP-925 which is high voltage, easy fix, the 3055 fail..
but i have a similar unit sold as a Watson W-25AM and this is only showing up to 7v output,
it varies fine down to maybe 2v.
after remove years of fag smoke stained dust and getting air circulation i started to look in to it but couldn't find any obvious,
this thread has many good points i will now check.
i'll report back once i have/if i repair it..
BUT here's one, what about an EP-925 that fails to switch on randomly ??
works fine majority of the time, other times just won't fire up ??
The W-25AM is a different design to the EP-925, these use a LM358 opamp for voltage regulation.
Check, clean or replace the voltage adjustment pot on the front as these are common to fail (I remove them and fit an internal resistor or pot), so are the open skeleton adjustment pots on the main board so check those too.
Check the obvious like the series pass transistors and drive transistor. But I wouldn't be surprised if it's the front voltage pot.
Odd fault with the EP-925, try switching it on and off at the wall to rule out the switch on the front of the EP-925, it could also be a dry joint somewhere on that horrible PCB that's attached to the front.
Check if there is any power on the primary/secondary's of the transformer when it doesnt fire up, then check the bridge rectifier and the aux output which is half wave rectified on the main PCB.