Vintage Synth Repair

I have a JX3P that was unused for several years.

When first powered on, some of the lights would come up but there was  
no response to pressing any of the controls or keys, nor would  
incoming midi have any effect. There was a faint soft white noise that  
slowly panned from left to right and back again reminiscent of the  
chrous sound.

My first thought was to replace the battery, but having done that I've  
clearly made it worse. Now when powered up, there is no sound at all  
and nothing lights up. The only sign of life I can get from the unit  
is that the LFO trig button will light up when pressed but goes off  
again when you release the button.

I talked to Roland here (Sydney Australia) who basically said there  
are no spares for that unit any more so there's no point bringing it  
to us.

I also have a D5 that has several dead keys. It's not due to dirty  
contacts - I gave it a thorough clean and they're still dead. It also  
has the weirdest sound glitch I've ever heard - this is me playing C  
and E together: http://www.elderwyn.com/d5glitch.mp3 ... what's  
interesting is that the demo song plays perfectly (no glitching) so  
I'm guessing the keyboard control circuits are the culprit.

Any suggestions on either?

Thanks,
Gwydi