Patches and discussion for Ensoniq VFX family

Hi All . . . I've just joined the group. I used to own a VFX (I 
bought one of the first), and kept it for 3 happy years before part-
ex ing it for a Korg 01/Wpro . . . big mistake . . . I wanted my VFX 
back after a week, but the shop had already sold it!. I bought a 
second-hand VFX a couple of years ago in non-working order, and have 
done various repairs (actually it was dead simple . . . fuses, new 
ROMs, clean the cartridge connector, new battery etc. etc).

I now have a problem I can't work out . . . I don't think it's 
related to the infamous "Calibration" fault, but I wil bow to 
anyone's better judgement. If I leave the VFX off for a long time
(days), when I turn it back on I get either a "Keyboard Receive 
Error", or a Calibration error (If I ignore this none of the notes 
work). If I leave it on in this state for about 5 minutes a couple of 
soft "clicks" can be heard, and if I reboot all is well (apart from a 
few "ghost" notes until it's really warm). If I leave it on for a 
while I sometimes can hear the odd soft click, so I wondered about 
the dodgy connector . . .

Now before I wield soldering Iron to implement the Calibration fix, 
is this going to solve the problem, or should I just bin the Keyboard 
module and get another one? I've got all the schematics EXCEPT the 
Keyboard Module, and the Service Manuals, but there is no mention of 
this error.

Any ideas anyone?