Recently purchased autobias boards for my m-125, assembled and installed with little difficulty. When tuned on, all leds blue, seemed to work, hooked back up and 1 worked fine, other did not, all tubes look lit, however, no sound at all. Took back apart, reinspected all wiring multiple times, all seemed correct, no shorts or other loose wires, Get copy of schematic, voltages erratic and off, assumed meter not working. Nopted that rectifier did not seem warm at all. Turned out that the rectifier had blown, changed it an now works, Don't know why rectifier burned out, but was surprised that tubes still seemed to look fine. I bring this up in hopes that if this happens to someone else they will find answer easier than I did.
2 posters
M-125 problem resolved, rectifier fried
cci1492- Posts : 331
Join date : 2016-05-09
Age : 64
Location : NJ
Thanks for posting. When possible, can you post a shot of how the board looks installed on your amps? One of the things (there are many) that I love about the M-125s is how much room there is for the wiring.