I have two Sony receivers, GX69ES and GX67ES, which have the same problem. There is intermittent noise in either one or both channels that does not vary with the volume control, and after the unit is on for a while the sound cuts out completely and there is a blinking red "P" on the display.
I asked at a local repair shop and the guy says it might be a problem in the preamp stage and, if so, that's about $150 to fix (one unit, which is all I need).
These are units from the early 1990s, both of which I bought used. I started with the 69, but after it developed the problem I got the 67, which I've had for maybe a year, but now it's got the same problem. I've used them in stereo mode only, not multichannel. Sound-wise, I like them a lot.
I'm thinking that since both units are malfunctioning in the same way, this may be a common problem, and someone might know whether this is the sort of thing that can be repaired, or whether, say, the units are too old and liable to fail again.
Incidentally, I have been running the preamp output to a sub controller and then feed the output of that back into the main in. Sometimes I wonder whether that setup is causing a problem, although I'm pretty sure I have it configured correctly.
Thanks in advance for any advice or ideas.