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Old 24th March 2013, 04:14 PM   #11
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Russ,
I can't measure current on the right channel. Voltage is at B+ using R18. What can be the problem now? Thanks. Godspeed.
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Old 29th March 2013, 04:16 AM   #12
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Help. Amp still not working. Here are the voltage measurements: with just rectifier in place

B+ =420
B- =-281
R18=420
R29=420
R34= -176
R33= -149
Caps =420
R14= -178
R25 =-283

Anyone? Thanks. Godspeed.
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Old 29th March 2013, 04:07 PM   #13
rknize is offline rknize  United States
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R33 and 34 should change when you turn the bias adjustments. What happens to the two channels when you do this? You see current floating through the bias resistors on one channel but not the other?
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Old 29th March 2013, 04:19 PM   #14
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Hi Russ,
Thanks. R34 voltage change (more positive) when I adjust the pot but not with with R33. Yes, I can't measure current on R18. I already change the CCS chip. I will also replace the follower chip later today if necessary. Godspeed
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Old 29th March 2013, 10:26 PM   #15
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It could be the FET. Check that the voltage at R15 changes when you move the pot.
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Old 29th March 2013, 10:36 PM   #16
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Thanks Russ. Measure on the side of the pot or side of the cap? Godspeed.
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Old 30th March 2013, 01:49 AM   #17
rknize is offline rknize  United States
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Both sides should be the same.
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Old 30th March 2013, 09:50 PM   #18
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Hi Russ. Thanks for your help. I think I got it. Preliminary measurements are all good. I replace Q1, Q2, U1, U2 and both the 100k pots. I was able to measure 175 volts on the plates of 5842s and 65ma on R18 and R34. After 5 minutes of being on, the amp retained all the measurements mentioned. I'm happy but the problem is that by replacing all those parts, I cannot pinpoint what was the culprit originally. Thanks again, Sir. Godspeed.
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Old 31st March 2013, 12:11 AM   #19
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I'm glad you got it working.
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