Sounds like only one amp is working. Then after a few minutes the red light goes on and the unit shuts down.

Your unit is telling you that there is something wrong. This can be in two places, your power supply is shutting down (thermal) because of a component fault, and or your Amp(s) are overheating due to also a component fault. My guess, for what it's worth, is one of the amps has a bad final so I would disconnect the power supply from the amps and see if the unit keeps running. If it does than re-connect one amp at the time and see what happens. This should get you a fair way in to finding the fault. Have fun.

Not likely a grounding problem. Run a test: Turn on unit with NO sound into the mics and wait 5 minutes... now try the mics. If they start working for a few minutes, then the amp is being overdriven. These small systems can be overheated and a thermal protector shuts them down to protect them. A hidden problem is if the mics are in front of the speakers you MIGHT have ultrasonic (above hearing range) feedback that may be overheating the unit. Put your speakers nearer the audience and mics behind. If problem persists, exercise your warranty.

It's shutting down automatically due to heat peaking. You need to turn off until you are ready to use it.

Holding the page up and down buttons while powering on supposedly resets it. I have no sound except demos, but no lights showing like yours, and williams tech support said to reset that way but it didn't seem to do anything. Good luck hope this helps!

Since the PA clip is not lit, the problem seems to be up front...

First thing is to look for a bad cable as a broken ground could be putting hum at a clipping level. First thing, test this by unplugging all inputs. If the clipping light goes out, then you have bad cables or a ground loop.

Try sending a line level signal into "Effects return" to test if the power amps are OK.

If the clip light is still on, turn all gain controls down to minimum. If light is still on then take unit for servicing.

It sounds like you have either a hard drive failure or have lost the internal operating system in your unit.

BE VERY careful if you have critical data as it still might be recoverable.

I would contact the factory on this one.

It sounds like the guitar level input to the unit is too low.

NOTE: With this product you MUST use an amplified or electric guitar that has a preamp within it.

If you have a straight guitar that does not have an amp in it, buy a preamp to first run the guitar through.

Our bassplayer had the same problem with his mb4410. As it turned out, the fan was not working when the amp got hot. It did turn when cold - go figure! Swap the fan for a good quality (Pabst, Sunon) 80mm pc fan with 2-wire connection. Three or four wire fans will not work w/out modding. See your local pc guy and ask for an unregulated, silent 24/7 fans. He will know. Our bassplayer sold the P.O.S. while still in warranty. HTH.

go back in and find where the electrolitic capacitors connect to the board. They look kind of like a battery. One or both of them have broken loose from the main board, preventing any significant current from going to the output transformer, and causing overload. This is a common problem, and it does not take much rough handling to cause it.
where the break is is at the solder connection. Under a magnifying glass, the break will look like a little circle. Float fresh solder on that or any other large solder joints which may be cracked or broken.
Use standard precautions when working around high voltage.