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Re: 250-4 [message #28620 is a reply to message #28618]

Thu, 23 June 2022 17:17

kb0rex
Messages: 33
Registered: June 2022

Member

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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[Message index]

		250-4 By: kb0rex on Wed, 22 June 2022 16:29
		Re: 250-4 By: chicagobill on Thu, 23 June 2022 15:49
		Re: 250-4 By: kb0rex on Thu, 23 June 2022 17:20
		Re: 250-4 By: kb0rex on Thu, 23 June 2022 17:17
		Re: 250-4 By: kb0rex on Thu, 23 June 2022 17:17
		Re: 250-4 By: kb0rex on Thu, 23 June 2022 18:09
		Re: 250-4 By: kb0rex on Thu, 23 June 2022 19:45
		Re: 250-4 By: stevem on Fri, 24 June 2022 06:20
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 10:50
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 11:00
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 11:23
		Re: 250-4 By: stevem on Fri, 24 June 2022 11:23
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 12:19
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 12:34
		Re: 250-4 By: chicagobill on Fri, 24 June 2022 12:47
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 13:56
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 14:42
		Re: 250-4 By: stevem on Fri, 24 June 2022 15:09
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 15:47
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 16:07
		Re: 250-4 By: stevem on Fri, 24 June 2022 16:49
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 17:22
		Re: 250-4 By: stevem on Fri, 24 June 2022 19:15
		Re: 250-4 By: kb0rex on Fri, 24 June 2022 22:16
		Re: 250-4 By: kb0rex on Tue, 28 June 2022 14:43
		Re: 250-4 By: kb0rex on Wed, 29 June 2022 12:12
		Re: 250-4 By: stevem on Thu, 30 June 2022 06:12
		Re: 250-4 By: kb0rex on Mon, 04 July 2022 13:19
		Re: 250-4 By: stevem on Mon, 04 July 2022 17:02
		Re: 250-4 By: kb0rex on Mon, 04 July 2022 22:03
		Re: 250-4 By: kb0rex on Fri, 08 July 2022 23:37
		Re: 250-4 By: stevem on Sat, 09 July 2022 17:15
		Re: 250-4 By: kb0rex on Wed, 13 July 2022 12:58
		Re: 250-4 By: kb0rex on Wed, 13 July 2022 14:59
		Re: 250-4 By: kb0rex on Wed, 13 July 2022 15:13
		Re: 250-4 By: stevem on Wed, 13 July 2022 17:17
		Re: 250-4 By: kb0rex on Wed, 13 July 2022 22:18
		Re: 250-4 By: stevem on Thu, 14 July 2022 05:51
		Re: 250-4 By: stevem on Thu, 14 July 2022 07:17
		Re: 250-4 By: kb0rex on Thu, 14 July 2022 12:25
		Re: 250-4 By: kb0rex on Thu, 14 July 2022 11:27
		Re: 250-4 By: kb0rex on Thu, 14 July 2022 11:56
		Re: 250-4 By: kb0rex on Thu, 14 July 2022 12:08
		Re: 250-4 By: kb0rex on Thu, 14 July 2022 12:09
		Re: 250-4 By: kb0rex on Thu, 14 July 2022 13:19
		Re: 250-4 By: kb0rex on Fri, 09 September 2022 16:46
		Re: 250-4 By: stevem on Fri, 09 September 2022 20:06

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