Integrated stopped working

Thanks for the response.  I don’t have headphones connected or another device used for trigger.  What’s weird is the red standby light should come on, but doesn’t.  I could be wrong, but would think if it needed a trigger, the standby light would at least be on?  Not sure.  I’m an engineer, but not with electronics.

You can try unplugging the m100 from the wall and let it sit for about 15 minutes and then plug it in and try it. Sometimes microprocessors in components need to power down completely to reset. Good luck.

Cheers,

Scott

So let me get this straight- With the unit plugged into power and turned OFF the red standby light should be ON, but its not?

If that is the case then, duh, power is not getting to the unit. If there's power getting to the end of the power cord, and the fuse is good (did you do a continuity check? Or just eyeball it? If so that's not good enough. Check continuity) then the circuit is open somewhere past the fuse.

Open it up and have a look. Odds are its a fuse and it looks good when it isn't. Been there, done that. If its not though then your next likely culprit is a bad solder joint probably somewhere very close to where power comes in. Electrical resistance at joints and bends creates heat, expansion/contraction cycles creates cracks, eventually over the years it can fail. Cross your fingers as these are the obvious and easy fixes.

If you don't have anything connected to trigger then it has to be something else.  I agree that standby light should be on, even if something in software or lack od signal prevents M100 to turn fully on.  Could it be something trivial, like bad power cord or loose spade inside?  Did you measure voltage at the end of the power cable? (try to wiggle cable and connections).  Are you sure it is pushed-in all the way?  Did you measure fuse with ohmmeter?  Is there any other fuse inside? (be careful - disconnect power).  I'm just grasping at straws.

I agree with millercarbon that it might be bad electrical connection.  I have Benchmark DAC3 that suddenly stopped receiving signal from remote.  I opened it and found that infrared diode was poorly soldered on one side.  It was side of ground plane that required more heat to solder properly.   You can try to gently shake/twist it.
Samac has good point that circuitry, including stand-by light, is controlled by micro, that possibly needs reset.  Good luck, let us know.