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PostPosted: Mon Apr 11, 2016 1:16 pm 
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Built this unit about 3 years ago. Has been working flawlessly this entire time. Two days ago I hooked it up and got nothing but a high pitched very low volume wine and what sounds like space noise... Isolation transformers still seems to be doing their job though. Have no idea where to begin. Replace all the chips first? Any help would be much appreciated. Thanks


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PostPosted: Mon Apr 11, 2016 1:54 pm 
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I would start by taking voltage readings on IC1, 2 & 3. Place your DMM’s black probe on the center pin (ground) of the adapter jack and probe pins 4 & 8 of IC1, 2 & 3. On my router I get +8.2V on pin 8 and -7.7V on pin 4 of each IC.
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PostPosted: Mon Apr 11, 2016 8:01 pm 
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Thanks, Stephen. Got about the same voltage readings... 8.3 and -7.7

Just hooked it up again and the it's not completely dead. B passing signal fine, in B out B.


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PostPosted: Tue Apr 12, 2016 5:36 am 
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OK, it looks like the charge pump is working normally. The next thing I would do is compare the two signal paths with a signal probe. Since path B is working correctly compare it point by point to path A to see where the noise first appears in the signal path.
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