High Pitched Whine from Board that drives mini marquee panels

Ever since I first purchased my big red, 4 slot, the board that provides power to the mini-marquee luminescent panels has emitted this horrific, high pitched whine. It's so loud that as soon as I got the cabinet home, I disconnected the lead and have had sad, dark mini-marquees ever since.

BTW, I'm not talking about either of the two large circuit boards onto which the light panels themselves are mounted. I'm talking about the smaller board, that is mounted on the back of the wood panel, onto which the speakers and forward facing light panels are mounted. This is the actual board itself:



This little S.O.B. is piercing my brain with its high pitched, electrical wailing. At least to my eyes, there isn't anything obvious that is failing. No blackened spots, no leaking goo, but I am a complete electrical n00b so any advice on how to shut this thing up so I can again have some pretty, bright mini-marquees would be appreciated.

replace those caps for starters. did it light up when it was whining? that board converts low voltage (around 12) to the very high voltage the bulbs require. that heatsinked chip is my next guess. but youd have to measure input voltage and id do a reflow too.

This is common if/when the el panels start dying. I've heard that replacing them will fix it, but I've just left mine unplugged ever since

Guys, thanks a lot for the input. I think you may be on to something. I'm not sure if it's the transformer, or the heat sink, but it's definitely one of the two, listening to it when it's hooked up.

And if I recall correctly, when I first got the cab back at the end of the 20th century, the fourth light panel was burnt out. If burnt out panels contribute/cause the whine, I'm wondering if I can simply replace the broken one (or all of them, while I'm at it) and get the wailing to stop. Hopefully, the board pictured didn't get fried while it was still on location with a burnt out light panel. I tried doing some searches for the transformer and all I could find was documentation; no part to buy.

Thanks again for the input.