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I bought a Mitsubishi M-VR700 which produced no audio from the speakers, but with headphones, a tiny bit of audio was detectable with the volume control on max. This solution was posted on fixYa by Mojorisin65 some time ago: "Facing the receiver directly behind the MITS logo & power button is a vertical board with a large IC on it, try flexing the board near the IC while turning the reciever on & off or changing input modes, there is a cold solder joint on this board which I haven't found yet. I understand this is a common problem with the MITS M-VR700-900, Onkyo TXDS-575, & Integra DTR5 or DTR5.1 (all made by Onkyo)."
I gently flexed the board as described, and Boom, all audio was back as it should be. I suspect Mojorisin65 is correct about the cold solder joints, but with SMT components, it could be very difficult to find. It may very well be on one or more of the 48 pins on the large IC. This IC gets rather warm during operation, which may explain why some units may work until it heats up. The chip gets warm, and ‘twists” enough to lift the bad pin(s). In an attempt to deal with this symptom, I superglued a TO-220 heat sink to the top of the IC (don’t let it touch the case of C-716). The heat sink is dissipating a fair bit of heat, and so far, this ‘fix’ seems to be doing the trick. RJD 10.18.11
I gently flexed the board as described, and Boom, all audio was back as it should be. I suspect Mojorisin65 is correct about the cold solder joints, but with SMT components, it could be very difficult to find. It may very well be on one or more of the 48 pins on the large IC. This IC gets rather warm during operation, which may explain why some units may work until it heats up. The chip gets warm, and ‘twists” enough to lift the bad pin(s). In an attempt to deal with this symptom, I superglued a TO-220 heat sink to the top of the IC (don’t let it touch the case of C-716). The heat sink is dissipating a fair bit of heat, and so far, this ‘fix’ seems to be doing the trick. RJD 10.18.11
