[sdiy] Korg Drum Machines

[Chromatest Pantsmaker]

Hey all.. I recently got two Korg Drum machines..
a DDM-110 and a KPR-77

the DDM-110 is digital, and dead.
the KPR-77 is analog and also dead.

the DDM-110 has LEDs that work.   when it is powered up, the led's
flicker and various button presses make the LED number display various
lines.  it doesn't make any sounds (from headphone at least.. haven't
tested else)  there is a resistor inside that is fried... don't know
the value, but it seems to be on the tape-interface circuit, so I
wouldn't think it would cause any major problems... any thoughts? 
schematics?  experience with this?  oh, it does the same on batteries
and power supply.

The KPR-77 *was* working some when I got it.  the Tempo LED flashed in
accordance to the Tempo Pot setting.  but there was a rattle in side
(what's a battle?)  I found a machine screw and nut in there... and
now it doesn't even seem to power up...

btw.. the KPR-77 is a nice set up it seems with several pcbs in
there.  there is one, that I am calling a filter board, as I have no
idea what it does.  it mainly has diodes, caps, and resistors on
it..and 5 ic's (all HD14069UBP)... well.. anybody have schemos? tips
Ideas?

thanks..

-ben