Rhodes Chroma Polaris

Hi there. I just got a Chroma Polaris on Ebay, and it isn't working 
right. When you turn it on many of the led's light up, but the same 
ones don't come on every time the switch is turned on and off again. 
Sometimes the same ones will come on a few times in a row but then if 
you leave it off for a couple of minuites a different combination of 
lights will come on. The keyboard makes no sound whatever, and pushing 
any of the buttons will not turn on or off any of the leds. The 
keyboard appears to be in great condition, and the membrane switches 
don't look worn at all. I'm pretty puzzled as to what could be going 
on, or what to do about it. You would think even if the membrane 
switches were shot, the keyboard would at least turn on with one patch 
loaded. Anyone else had a similar problem? Thanx for any help you may 
have.                                -Bob