PVM-1354Q Turns On and Off - now tally light is red/orange

[Dochartaigh]

Sony PVM-1354Q Monitor: it has a beautiful pictures (great geometry even), but after about 10-15 minutes the monitor will turn off, then on, then off again, repeatedly. There is a distinct clicking noise which sounds like a relay when this happens. While it turns on/off the LED light for the on/off button stays lit, but the lights for the Line A RGB and Ext Sync will flash on/off with the monitor (if that matters).

With the help of a local arcade club we replaced all the caps on the power board, and this still happens. After leaving it on (and honestly forgetting about it for about 40 minutes), I came back to the tally light being lit red/orange, and it won't even display a picture now (just turns straight on to the tally light being lit).

Any idea of what this might be, and what else I can try to fix/replace/diagnose? I'm really a novice at all this, and don't even know how to use the multimeter I own, but I'm willing to learn and try anything you all suggest. Thanks.