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This is a unit I changed caps on. Cust found at a yard sale for $5.
One main filter cap burst open at some point and there were remnants all over the amp. Cleaned it up.
Amp worked fine unloaded and with resistive load, DC offset .044V, scoped output looks ok.
When the amp is loaded with a speaker, it has a 10vdc offset and hums. Limiter bulb is partially lit up.. not like a short though.
My Sencore Variac blew up last week, so I was using a Lamp Limiter.
I'm thinking this is one of those oddball situations where the Limiter Bulb circuit is messing the amp up.
Old 70's Ampeg B115. Came in with bad cap (I replaced them both), busted pots (replaced) and bad power cord (also new).
Speaker in cabinet was also open, so my concern was the DC offset destroyed the speaker originally or when the cap opened.
Nobody knew what was wrong with it. Customer said it never worked but came on (power light). Cab speaker was open.
Being I only have that Bulb Limiter (100W Incandesc) for now (until my repaired variac comes in next Tues), should I try the amp with a 250W bulb in the limiter?
Thx
One main filter cap burst open at some point and there were remnants all over the amp. Cleaned it up.
Amp worked fine unloaded and with resistive load, DC offset .044V, scoped output looks ok.
When the amp is loaded with a speaker, it has a 10vdc offset and hums. Limiter bulb is partially lit up.. not like a short though.
My Sencore Variac blew up last week, so I was using a Lamp Limiter.
I'm thinking this is one of those oddball situations where the Limiter Bulb circuit is messing the amp up.
Old 70's Ampeg B115. Came in with bad cap (I replaced them both), busted pots (replaced) and bad power cord (also new).
Speaker in cabinet was also open, so my concern was the DC offset destroyed the speaker originally or when the cap opened.
Nobody knew what was wrong with it. Customer said it never worked but came on (power light). Cab speaker was open.
Being I only have that Bulb Limiter (100W Incandesc) for now (until my repaired variac comes in next Tues), should I try the amp with a 250W bulb in the limiter?
Thx
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