Intermittent output Fender Vibrolux Reverb

[shzmm]

Just a follow up to this thread...

I think I have finally found the culprit-- the only elements after the output tubes were the output transformer, the speaker jack, speaker cable and the speakers themselves. After eliminating all of the above, I realized that the one common element was that I had retained the original 1/4" Fender plug and rewired the connections. It is one of those things I never think about, after all a jack looks alright it should work alright, right? When I clipped the output signal directly to the speakers, the amp worked fine. So I changed the output jack and still the problem persisted. It seems at the moment that the new plug is working fine.

However, since the user of the amp complained of problems even with an external cabinet, I will keep testing for awhile and see if I can get it to go bad again.

Thanks again for all the help and patience. I appreciate it!

[Enzo]

This happens now and then, so file it away for future reference:

The main speaker jack has a shorting contact, a shunt. It touches the tip contact when the jack is empty shorting across the jack. PLug into the jack and it pushes the tip contact aside, opening the shunt. Sometimes that shunt contact is not properly formed, and it can do a couple of things. One is that the plug might not quite push it far enough - ie it is too close, so it may sometimes still touch.

[TimmyP1955]

Your signal test includes all the way to the output tube plates?