Korg Poly800/EX800 Users

Hi Mike,

thanks for the offer; I think I have figured it out now.

KLM-601 and 601a are almost identical. KLM-601 was used in earlier
revisions of the Poly-800, KLM-601a in later revisions of the Poly-800, the
Poly-800II and possibly the EX-800. The Poly-800 service manual does not
mention the 601a at all, only the 601. But the the Poly-800 service manual
also does not mention a memory backup battery so it might cover only the
early revisions.

KLM-601 regulates the joystick bend range (VR1 and VR2); KLM-601a does this
too and in addition regulates the Master Tune range (VR3). R159 is required
for a KLM-601 board. When using a KLM-601a board R159 is NOT required; R3
on the KLM-601a board is used in its place.

As to why one of the Poly-800's did not have either a 601 or 601a installed
- that's a mystery to me. I'll probably build a replacement 601a for it.


> sorry for the delay in getting back to you. I have an original EX-800 service
> manual and that section is much clearer. So if you still need help, let me
> know and I will have a look at it and let you know the details. I think your
> thinking is correct in that you need R159 or otherwise master tune cannot
> work.
>
> Mike.
>
> --- In korgpolyex@yahoogroups.com, Malte Rogacki <gacki@...> wrote:
>>
>> Hello,
>>
>> I'm still trying to fix my dead Poly 800's; and I've made some progress.
>> I'm still trying to figure out the various revisions and related boards.
>>
>> #1 (working): "old" revision (without battery solder pads), KLM601
>> #2 (partly working): new revision (with solder pads) but no battery
>> pre-installed, no KLM601 or 601a
>> #3 (non working): new revision with battery installed, KLM601a
>>
>> #2 works actually pretty well; however Master tune would not work and the
>> joystick would make some problems (bending only upwards, bend range only
>> zero or full). Close inspection reveals that R159 is not installed here;
>> however the PCB looked as if no KLM601/601a was ever installed before.
>> Strange.
>>
>> Since this part in the schematics is very hard to decipher here are my
>> questions:
>>
>> 1. Am I assuming correctly that for KLM-601 to work R159 has to be present?
>> Or is a wire jumper needed instead? I don't see how the Master tune would
>> otherwise be connected at all...
>> 2. Does the absence of R159 indicate that originally a KLM-601a was to be
>> placed here?
>> 3. Could KLM-601 be just omitted at all and instead R159 be used?