Troubleshooting blown reveiver

Discussion in 'AV Receivers' started by mkgrenwel, Jan 29, 2013.

  1. mkgrenwel

    mkgrenwel Auditioning

    Jan 29, 2013
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    Please forgive the length of this post, but I want to get all the details in that I can so maybe someone can diagnose what's going on. I got an Onkyo 7.1 HITB (HT-R570) a few years ago and it's prtty much given me nightmares ever since. After about a year of use in a cabinet without enough ventilation, (open front, closed back, DVD sitting on top of receiver, not muh clearance on either side, because I didn't know any better) it started making a clicking sound periodically while in use. Shortly thereafter, it shut down and would not come out of protection mode, even days later. I had it serviced and it came back fine, but within a month started making the same clicking sound, and then shut down completely again. After a second servicing I reconnect everything, stil in the cabinet with a closed back, but this time with a few inches clearance on top. This time I never got to any clicking sound. I simply turned it on and heard a popping sound. It would then turn on and everything, but no longer output audio to anything. At this point I found a short in one of the speaker wires, so I suspect this is what caused this problem. So third servicing happens, different repair shop this time. I get it back and reconnect again. Two days later it blows again, popping sound and all. It's at this point that the shop tells me about speaker impedance and shorted wires and all that stuff i should have been aware of but wasn't. Unfortunately I did not check the speaker connections to the unit before disconnecting, so I don't know if there was something wrong there, but I have been able to examine the wires and connections to the speakers. I found one of the wires I had stabbed with a thumbtack, but in testing with an ohm meter, I was never able to completely confirm that this wire was shorted. The rest of the connections looked OK. I tested all the speakers and got 6 ohms, which is what they should be. The repair shop told me specifically that it was the right surround channel that had blown. I have the unit back now after the 4th repair. I bought new speaker wire to replace the one I had stabbed, as well as another that had been spliced. i currently have the unit outside of the cabinet entirely, giving it 360 degree clearance. I also have not connected the right surround speaker. My question to you guys is what can I do to make sure this thing survives? Did the (probable) overheating early on damage the units protection features, which is what allowed me to blow it with a short circuit? Do I have a bad right surround speaker? Are the first two and second two failures unrelated coincidences? With all new wire, a new right surround speaker and lots of attention paid to temperature control do you think this unit can live to a ripe old age, or did past abuses doom it?

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