I'll try and keep this short and sweet.
First the problem: the receiver will intermittently (with no perceivable consistency) produce a loud popping noise that may be brief, or may continue as loud static (very similar to the noise of a radio station with no signal: white noise).
Trouble shooting: the noise is produced through every speaker and on every input (regardless as to whether or not an IC is plugged into the input the receiver is set to). The noise will diminish or increase if I adjust the volume, but it's always louder than what a source would play at at the same volume. ICs have been swapped, speakers and speaker cables have been swapped, power outlets have been swapped, and sources have been swapped but the same noise occurs.
Sometimes the receiver stays on for a few hours without making a noise, sometimes it occurs within 30 minutes.
I'm at a loss, I've taken the dust cover off and didn't seen any signs of blown caps or shorts etc. ... though I wouldn't say it was an extremely thorough look since I didn't really know what I was looking for. If you guys have any other suggestions I'd greatly appreciate it. I'd love to be able to salvage this receiver.