2k oscillation in my Eighty-Eight (Help!)

[88 man]

My EightyEight suitcase has been reliable for years (and stationary) but recently I turned it on and heard a nasty oscillation which now won't stop.

After about a minute it settles to a frequency of about 2kHz.  I'm guessing I have a bad capacitor somewhere. When I switch on or off, the frequency changes – which to my mind would be the sound of the cap charging/discharging.

The sound is independent of the volume control and is just as loud with the volume at zero as it is at full volume.

I generally am more nerdy about recording than opening up the machines and tinkering, but if you can give me a good idea what I'm looking for, I'm inclined to take care of this myself (yes, I know to discharge power caps so as not to die, and I can read a schematic).

Thanks so much
s

[Ben Bove]

I'm guessing its the 4 pin, 3 concentric knob Rhodes?

Or is it the 5 pin with slider/independent knobs for EQ?

[Rob A]

I think you have the right idea. Pick the right drawing from here: http://www.fenderrhodes.com/org/manual/ch11.html
and tear into it.

[Mark II]

do you hear this noise also when using the preamp outputs ?

Mark II