K2000 - 'Hum' Problem - no sound?

I have a K2000S I’m like to bring back to life. All I get right now out of the keyboard is a faint hum - no sound. Is there a common failure (e.g. in the power supply or one particular board ) that I could try a fix to see if I can make some use of it. I loved the keyboard, but it’s been a long time since I’ve played or used it. I’m the original owner, but had it in a closet for the last 10+years. Appreciate any advice

The K2000 is like the K2500 in that it uses AA batteries for the memory backup right? might be worth ensuring those haven’t leaked and caused damage. But if you rule that out it would be worth first checking the power supply output is as expected, that the voltages aren’t too low and high. Naturally you need a scope or a multimeter for that.

If power supply is okay, try a factory reset. After that you’re in the territory of component level diagnostics I’m afraid.