Anyone experienced in repairing a Matrix-1000?

[David Brown]

Anyone have any experience in repairing one of these?  It doesn't play 
correctly - it seems like one of the oscillators is off but I think they're 
just not programmed right.  When it's not working the front panel behaves 
crazy where the "2" button acts like the "1" button and the "9" button acts 
as "enter".  I've taken it apart a couple of times and afterwards it works 
for a while and then acts up again.  First I thought it was the keypad 
buffer.  It acts as if BD0 and BD1 are slightly shorted together.  I 
replace the buffer and it worked for a while.  Later, the wires between the 
main board and keypad were shorting so I replaced them all.  I replaced the 
battery as well since it was getting low.  Again, it worked for a 
while.  This morning it's acting up again.  It's really intermittent.  My 
assumption is that if the data bus is screwed up there's no way it's going 
to sound right so I've been trying to focus on that first.

Any hints or prior experience?

Anyone out there that repairs these?

Thanks
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     David Brown
djbrow at pacifier.com