M500 intermittently drops the right channel.

M500 intermittently drops the right channel. Could someone give me starting points for following thru the circuit to troubleshoot it.

Many thanks,

Gonna be hard to diagnose when it's intermittent. You probably need to wait until it fails solid to track it down. Is there some way you can make it fail consistently?

No consistantly. Sometimes when it goes down its down up to 5 minutes then on then off again.

I would check tax records, sounds like your house was built on top of a graveyard?

Roy, check for a cold solder joint. That is, any solder joint that isn't shiny or looks funky should be touched up.

I would check tax records, sounds like your house was built on top of a graveyard?

Hehe....

Good call, Jesse. I just had an M-500t that I was working on that went bad for no apparent reason. It was a cracked solder joint.

Thanks guys. I am looking for schematics for the M500, are they the same as the M500t. As a tech I tend to look before I leap.

They are somewhat the same, but the M-500 has a couple of quirks. There's those little boxed daughter boards (two of them IIRC). One is the phase network and the other is the voltage regulator (both in the power supply). Nothing in the phase network of concern, but the voltage regulator has a bunch of caps in there. See below. Both boards were eliminated on the M-500t (parts became part of the mother board). There are some other parts on the M-500 that are missing on the M-500t, like the inductors on the amplifier board, and a network that may or not be there, based on the particular build of the M-500 that you have.

Here's the voltage regulator daughter board that was a real pain to work on. It is soldered to the mother board on risers that are also conductors.

M-500 daughter board.JPG (159.52 KiB) Viewed 340 times