I'm having a problem with my McIntosh 4300V receiver that started out with the left speaker cutting out at low volume. After turning the volume up, the left speaker would work again. This happened for a couple weeks, until the last couple of days, now both speakers will cut out intermittently at any volume, until I turn the volume up, which seems to work for awhile. I connected my Marantz 2270 to the speakers, and didn't have the problem once, so I'm pretty sure it's the McIntosh receiver. I looked at the schematic online, but can't seem to figure out where the speaker relay(s) is. Can anyone tell me where the speaker relay is located? I've already sprayed all switches and pots with Deoxit D5. Thanks in advance.