hifi engine

Realistic QTA-720 help

Bought one of these just to hear what Q-vox sounded like and found the front right channel
either squeals or just hums depnding on other settings. But no sound on that channel. Good Stereo sound through rear speakers with headphones and speakers. Anyone able to help point me to a service maunal or a board layout/schematic.

If/when I get this solved, then have an STA-77 with distorted right channel to fix.

Thanks in advance-
Gale W.

Re: Realistic QTA-720 help

Posting solution for this issue hoping to help next poor bastard. Never found Schematic. But realized that being a quad amplifier unit gave me three good amp cicuits to compare component measurements against the bad amp. Third time through, I finally found a transistor bad with the emitter leg literally snapped loose at the transistor body. Damn thing checked out OK from the bottom with a multimeter, but channel started working while I was pushing around on components from the top side. Could not see it snapped because it was wrapped in a bit of a tin heat sink(?). So Q-vox effect is pretty cool in separating frequencies front-back on the same channel, like very early surround sound. Wish I had some true quad channel sources to check out the unit's decoder operation.