ringing noise on rack piano patches..

[mcallyam]

hi,my Roland U-220 rack has a ringing noise(like a sort of high pitched feedback) which is pretty noticible on the piano patches, is this just somthing I have to put up with as how it sounds or is there a way to fix/alter this? Or has it just developed feedback owing to its age or somthing, but it seems strange that it only seems to affect the acc piano sounds...

(I've heard some people say the reverb sounds a bit metalic and ring like but I've tried turning this off and it doesn't help the problem, Ive also tried fiddling with most of the settings on the unit but to no avail)

thanks,

Al