Roland kr4500 sticky key and metalic sound


My 94 yr old neighbor has this piano with 2 problems

1 the middle E key not spring back. How6if pressing it successively, it springs back.

2 whenever i turn the piano on, it gives a high pitch sound…like distorted electric guitar…when I press the keys, they all have a high pitch resonance. I have yo turn off then on several times , then the noise subside. The keys play normally with no distortion.

What could be done?

I have got a service schematic manual. I have taken out the bad key, it doesn’t look dirty. I could see the spring(22175178Key Spring) but no idea if it is the culprit or not.

Would appreciate your reply

Thanks in advance

You could try swapping the bad key with a good one from another octave to see if the problem follows the key. You might get lucky and both will work.

The high pitched noise could be bad electrolytic caps. Look for bulging or leaking caps.