Fadal manuals are online someplace iirc.
Usb-connected volt meters, logging, maybe 60€ each, are available.
Get 2 or so, track power from whatever fails, upwards till mains power.
It might be main control stuff..
or just as well anything silly, like say a coolant pump, air-pressure solenoid, error-signal, or maybe a short to ground from one of the ancillaries, causing a power-down.
Try to find a way to make it fail reliably and fast.
Then keep disconnecting/bypassing stuff till it does not fail.
Work on power-2, binary,
Repeat 2-3 times.
Always disconnect/connect twice the stuff, no more or less.
Then work backwards, reconnect half the stuff from the failing block-o-stuff.
Do not guess.
Repeat.
Re-test.
Sometimes, one-affects-another unrelated.
A good rule, always, is replacing electrolytic caps on power supplies, transformers, similar.
Likewise, cooling electronics.
Cool electronics = 20+ year lifetime.
Hot, 1 year or less.
Your issue could very well be heat, with a failed fan somewhere.