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I have an old ultra plus that I would like to get working again. I loaned this amp out to a friend. He was using it and told me the amp only worked in the half power position. He returned the amp and it worked fine at half power. I moved power tubes around thinking maybe a tube went bad. I powered back up and heard a pop and power went out. Pulled the chasis and found a blown fuse. Amp sat for 6 years. Son has a punk band and begged me to get it running again. I repalced the fuse. Put in a new set of power tubes. Powered back up and got no sound. First of all things that struck me odd was the peavey logo was orange and would not switch to green or red. Not using footswitch. Also the red power light was on but the green status light never illuminated. Any possible help getting this old girl working again?
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it may be the screen grid resistors (SGRs) which should be 100ohms but blow commonly, do you have the full schematic? I can post of you can get from Peavey too.
I'd not put new tubes in until the problems get sorted out. check this old thread for something similar Peavey Ultra Plus - dead...
once reborn your son should love this amp! -
The lack of green standby light means ther is no B+ on the screens.
Generally caused by failed tubes, the most likely reason for this is the large 400 ohm 10 watt resistor on the power tube board. I bet it has gone open. If you don;t see 400 ohm ones, a 390 ohm will do nicely. 390 is a standard value, 400 is not.
This amp has a half-power switch? News to me.Education is what you're left with after you have forgotten what you have learned.Comment
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