Home » VintageKustom.com » Repairing Kustom Amps » 250-4 (got it burnt up to repair on my bech)
Re: 250-4 [message #28620 is a reply to message #28618] Thu, 23 June 2022 17:17 Go to previous messageGo to previous message
kb0rex is currently offline  kb0rex
Messages: 33
Registered: June 2022
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well I typed a long reply but apparently got logged out. So here is the short retyped version. I usually use the bulb limiter on any items I get into for repair. also a variac. On this on I replaced the worst first, the output's , which were shorted the drivers also and there 95.3 and 681 and .51 5 watters. I also replaced q6 and 7. So q4-13 have been replaced and the resisters associated with them. I also replaced cr1 and cr2 with 4007s to try and cool power section as its working now but hot. I have also at this time repaired the effects board to function and now this amp passes signal end to end with good volume. I just can't seem to get the power amp section to balance. I have not tried the diff amp q1 and q2 or changed q3. With power amp disconnected I have good +- rails at 40.3volts. This drops to 37 with power amp inline. So I am at a loss where to got.... I suspect the bias but don't know this amp well enough. Thanks for tossing me a life line.

Doug
Sad
 
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