You might want to take the psu off and have a look at the underside. There will be more ICs to inspect.
Careful though with the pins of the big crookedly placed capacitor. It can harbor a stinging voltage.

The blinking makes me think a short somewhere not enough to cause the fuse to blow, but enough to cause the regulator to trip and start again.

First thing I would do would be to sanity check the audio source, no DC voltage or huge amounts of AC hum picked up on it's cable suck that that would be tripping the power control in the monitor.

Second thing I would look to see if audio processing/amplification circuit could be separated from the internal supply and powered for test independantly, if it seems to work and produce non distorted audio, we'll make the assumption for now that it's working. If it won't work or makes robot noises or something we will assume it is failed and may be drawing more current than intended or shorting.

Third thing if audio checks okay, I would proceed on the assumption that the onboard power supply and conditioning had gone marginal, and start replacing capacitors.

That's just how I would attack it, see where it matches up with what you can do and have resources for.