# Denon AVR Repair



## mayhem (Apr 13, 2010)

Just received a used Denon AVR-4800 receiver. Nice unit. lots of features...free. Seems to work well except the right front channel has loads of static...the sound is not unlike that of a blown speaker. Left channel sounds great. Troubleshooting thus far: - Swapped the speakers to verify I'm using two good speakers. - Replaced the speaker wires . - Verified the source (ipod) is producing both channels properly, verified with headphones. - Moved source to second input, works the same. - Hooked up headphones to the receiver, both channels sound great. - Cross connected L+ and R- to a speaker...sound is good quality. - Cross conencted R+ and L- to the same speaker, lousy sound. My guess is and processor are working fine, the problem seems to be isolated with the right positive speaker terminal, so I think the amp itself has a bad channel. I'm getting a lousy quality signal out of it, but I'm not sure of where to go from there. I popped the cover off and traced the positive terminal back to where its soldered onto the board, I get distortion there as well so its not simply a bad connection to the terminal itself.

I do have a copy of the service manual and did some checking. There is the main output board that runs F-R across the top centerline, it has the 5 outpout channels on it and each channel has a tuning pot, which the manual gives tuning specs for (set for a certain read voltage across terminals at power-on, reset for a different voltage after runtime exceeding 2 minutes, etc). I can't get the right voltage readings on the right front channel pot though. Not sure if the problem may likely be on this board or down the line. I think if I want to ohm the pot out properly I'll have to desolder it from the board, right? Might be a good test to simply swap it with another channel's pot and see if the problem moves. Thoughts? Maybe a symptom of the problem, not the actual problem?

Sending out to Denon for is not a reasonable option for me, the cost of any repair will likely exceed the value of the recevier...this is more for fun and it'd be nice to have it running as its a damn good unit for my purposes (basic HT and loud music to good speakers).

Thanks for your advice.


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## mayhem (Apr 13, 2010)

Anyone? Beuller?


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## Volenti (Feb 17, 2010)

How far out are the voltage readings? It looks like a good place to start if they are a long way out, could be a powersupply/dry electrolytic cap issue.


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## mayhem (Apr 13, 2010)

Its been awhile since I volted it out so I'll have to double check the actual numbers. IIRC the calibration calls for readings around say 2-4v across the terminals and I had to switch my DMM up a range in order to read the bad channel. 

My DMM does capacitance too, can those be measured on the board or do I need to desolder so its isolated from the circuit?

I beleive the unit uses a single PSU and delivers up to 125w to each of the 5 channels, so I've been focusing on the channel output board for troubleshooting, maybe time to fully disassemble and look for discoloration and do the sniff test. No smells on the board I've been messing with.

I've also switched it into phantom surround sound mode so I put signal to each of the 5 output channels, all the channels except the right front sound crystal clear.

Where would you expect those sorts of caps to be? You mean the huge main power caps or the little disc caps that are everywhere?

Thanks.


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## XDanX (Feb 6, 2011)

I have the exact same problem with my AVR-1611 the front right channel has lots of static. Did you ever find a solution? If not did you find a workaround? I tried to sub a zone2 channel but I can't get it to output to those in surround mode.


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