Name:    Ed Goforth
Email:   goforthsound@yahoo.com  
Subject: MM 210-65
Thread:  22
Time:    Sat, 15 Dec 2001 10:43:51 UTC

Hi Dick, http://www.mojotone.com is having some Music Man replacements being made to spec from the original Transformer company that made them for Music Man. I am not sure if they are available yet, but you can check with them. I believe that those diodes were to supress extreme voltage surges to the power tubes, but when they go, they tend to short to ground. Have you tried the amp without the diodes in the circuit? If not, try removing them if you have not, the tranny may still work, but if you know the trany is bad, like a shorted winding, then I would check with Mojotone. Try the cross reference I have posted above, see if those diodes cross to a replacement. And good luck!
I did work on a Crate tube amp once that had diodes for power tube protection, they went bad, and the amp did not work of course, I called the Crate Tech back then, they said to just pull the diodes, this was then a revision they did. Another time I had added three 1n4007 diodes in series, on each side to the output tranny on a Mesa Boogie Mark III, like the Music Man design, when sending the amp back to Mesa to do some blues mods, they removed my diodes and bias pot! Gee thanks Mesa! They take any mods out of the amps, and claim these mods are not healthy! Well the bias mod is not healthy to Mesa's bank account since they sell tubes, go figure...


Ed