Korg Poly800/EX800 Users

hey everybody,

for those of you who have been asking about the moog slayer mod, the 
picture that olaf_nv uploaded is a nice, informative diagram.  atom 
smasher's original site didn't show you how to make the mod 
switchable, so if you want to keep the original filter functionality, 
it's definitely a good way to go.  props to olaf for the diagram, and 
also to peter ullrich (who i think i know from the sgroup list? ^^;;) 
for pdfing the original site.

fwiw, if you go check out http://www.synthmod.net/ you'll see a 
server message - evidently atom's domain has been having technical 
difficulties, but will it will be back online soon.  atom smasher's 
done some cool mod-work on things other than poly/ex-800s; it'd be 
cool to see it all in the form of an actual, organised site at some 
stage.

semi-gloating (but hopefully informative) part of message -

i mentioned in an earlier post that i'd found a mint, uninstalled 
mdk - for those of you who may not know, this is the midi dump kit 
for the original poly-800 (mk1), which gives it the ability to send 
and receive sysex information, and gives *you* the ability to call it 
a "poly-800 plus mdk".  it's a bit fiddly to install (some trace 
cutting is involved - i'm a kamikaze circuitbender so i used a dremel 
to do this), but otherwise fairly straight-forward.  with this new 
addition, i can now call my synth a "japanese reversed-keys korg poly-
800 mk1 plus mdk".  it has my ultimate respect, heh.

tech details - all you need to do is solder in 8 wires connected to a 
harness at various points on the klm-596 board, cut traces in three 
places (two of which are very close together, so really you're only 
going through the process twice), solder in two jumpers, replace the 
stock 2764 ep-rom with a preprogrammed 27128 that comes with the kit, 
add the new klm-680 pcb just above the battery case (ever wonder what 
those extra spacers were for?), then attach the harness to the new 
pcb and fire it up.  cross fingers and any limbs or other extremities 
you can.  assuming you haven't fried anything, it should work.

i've picked up soldering skills and such from my circuitbending 
adventures, but i don't know much about digital electronics.  
however, since i have the retrofit instructions here, i can scan and 
upload them at some stage - they include the updated memory map, full 
instructions for the retrofit, and a schematic of the klm-960 pcb, so 
i assume it would be possible for some bright spark (pun intended) 
with access to one of the programmed 27128 ep-roms and an ep-rom 
reader/burner to read the rom image, burn new ones, and then add this 
retrofit to their own (or others') poly-800s completely from 
scratch.  right?  the instructions say they're intended for use with 
the poly-800 service manual, but i got away without it, not that i 
was trying to do anything fancy.

as far as actual *usefulness* of the mdk retrofit goes, i'm yet to 
test this ^^;; - as hexafuzz mentioned in an annotation on the mdk 
user's guide currently residing in the files section (text version 
still on the way, i just haven't had time, sorry), you need software 
designed specifically to make the midi dump request to the poly-800, 
as it has its own unique "poly-800 plus mdk id" and refuses to send 
without it.  this is kind of unfortunate, but you should be able to 
set up any computer-based sequencer or sysex utility to do this.  as 
another option, there's the korg mex-8000 memory expander (which i'm 
kinda on the lookout for), which lets you load and save four banks of 
patches...  i think these are also really hard to find these days, 
because they work with many of korg's synths of the time (the dw-/ex-
8000, ex-800, poly-800 mk2, and poly-800 plus mdk - maybe others as 
well).  either of these options would be cool.  it's not so likely 
that a hardware sequencer will let you send the dump data request to 
the mdk, though - my mc-500 doesn't with the standard bulk libarian 
software, anyway, although i guess it might be possible to find some 
way around this.

so there you go.  hopefully that will help some of you with poly-800 
mk1s and a desire for some sysex action out; if anybody's desperate 
for the ep-rom image i can try to find a reader somewhere and make it 
available along with the schematics.  if anybody's desperate and 
*generous*, i'd accept donations for doing so...?  cash or ep-rom 
readers/burners gladly accepted, cash extra-gladly. *grin*  [sorry, 
i'm trying to save for a roland sh-5 and a modular, i'm in greed-mode 
atm.]

hope this is useful,

-gareth