Peavey escort 3000: the sound stopped working but is still powering on. What could cause? How can I repair it myself? Thank you.

Check on the back for a tubular fuse holder or inside for a fuse on the power board.

Peavey Support.

https://www.google.com/search?q=Peavey+Escort+3000

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Can't be fuses, as it comes back on!

Questions:-
i) Does it go off when run continuously with volume controls at zero?
(this checks whether the audio output level is causing a problem).

ii) When the unit does operate, is the sound good on both speakers?

iii) Does the fault occur more when outdoors (wind noise tripping the power protection). If so, reduce the low freq EQ setting.

iii) Do the EQ lights flutter when the fault occurs?

This fault has been reported on the Escort 3000 too, see link
Peavey Escort 3000 sound cutting out - Peavey Forum
suggesting this may need a 'electronic modification' to put it right.

Hope this helps.

sounds like an internal connection problem. open access panel and check the solder connection is not broken or loose. Be sure the metal mesh jacket is not touching the lead wire as that would cause a scratchy noise and feedback, or maybe near the internal cable causing feedback

power supply...take to shop.

Sounds like a regulator IC has blown. if you can replace these and then check the output before putting the caps in you can find out. You may have taken other circuitry out if it was enough over-voltage to cause the caps to blow.

It sounds like the power supply is overheating, or an interconnect is becoming loose due to excess heat. This might be due to a faulty heat sensor, but counter-intuitively could also be due to a low voltage supply, that is, drawing more power than the circuit can handle so the voltage drops. Please check that the outlet(s) you are plugging in to are rated to supply enough power.

Are you Pushing the system over its limits by Peaking everything. Sometimes they auto Shut off if your pushing to hard.

Clean all back switches, including the Stereo/Bridge one with a cleaning solution spray, then check functionality again.

A failure probably occured in one of the power amps and has blown the fuse or worse. DO NOT replace the fuse and try to operate it as further damage may occur. Take it in for repair.

Sounds like an imminent failure ready to happen. If it takes a bit of time before functioning, it may be getting overheated.
This is a small system... don't overdrive it as it is intended for SMALL venues of say 600 square feet.