1979 Pro Reverb problem

Status
Not open for further replies.
My .003 cap does just the opposite of what it should. It shows 360VDC on the back side and shows - MV's on the side that connects to V4-1 . That's my problem. trying to figure why it's backwards. I replaced the .003 cap with a new one , but it made no difference. The back side of that cap shows 360VDC and so does the outside post on the reverb pot...All my voltages are correct until you get to V4. Then V4 and V5 are all wrong.
I'd check those voltages on the tube socket pins with the tube REMOVED. It's possible that there's a short in the tube.
 
first things first DO NOT PLAY THIS AMP TILL IT'S FIXED.
360 VDC voltage in the reverb pot is not a good sign😱
it could be a short but could also be a problem with the ground = you can die.

check voltages on V4/5 without tubes and post it here.
then check voltage (without V4/5 tubes) on the reverb pot logs.
try to flip the ground switch to see if it changes anything.

there is a short somewhere and you need to find it.
 
I understand.... I haven't or won't try to play it like this. I only leave it on long enough to check voltages. I took out the tubes ...V4-5 tests 0 no matter which way you flip the polarity. Facing the front of the amp , the post on the left [green wire] , tests 360 VDC flipping the polarity doesn't change it. The middle post of the pot tests 0 the right post tests 0.
 
Status
Not open for further replies.