KLM-367A replacement board

About cKLM-367A replacement

Battery leak of an original NiCd battery in Korg Polysix synthesizer on programmer board KLM-367A (shortly 367A) causes corrosion of vias, parts’ mounting holes, electric traces and electronic components (caps, ICs, transistors and so on). Metal parts are covered with white oxides and blue-green salts. Corroded metal can’t conduct anymore, so part of programmer board fails and it is not possible to program sounds. 367A board provides besides other things control voltages for synthesizer blocks as VCO, VCF, VCA.

It is a very hard job to repair a PCB affected by battery corrosion. It is necessary to restore all affected traces, mounting holes, vias and to find not working parts (especially ICs).



Extremely corroded 367A board and new 367A (early batch) with transplanted connectors from the old board


Another solution is to use a cloned 367A, that’s why the name cKLM-367A. It is almost identical copy of an original 367A board. The parts are located on the same place and the board uses the same types of parts. The schematic of the circuit is as original one. The cloned board can be easily repaired and calibrated in the future using original Polysix service manual.

cKLM-367A uses some hard to find parts. These are original connectors, IC22 (MCU 8048-345).
Use original MCU from the old board. If your MCU is faulty or is missing, a replacement MCU is available.
If use of original connectors is desired, order variations „blank“ or „original“ (see below).

Q1 and Q3 were replaced by modern equivalents with same parameters.

Three 367A variations are available (see below). These three variations only differ in what is mounted into connector pads.

  • CN pin headers
  • CN original
  • CN blank



  • 1x new cKLM-367A clone board (choose your variation)
  • cKLM-367A is a drop in replacement for the old, original KLM-367/367A board
  • Regardless of a purchased variation all three variations come tested, calibrated and with factory presets to the customer! No need to adjust the cKLM-367A board!
  • MCU replacements are from NEC or Intel


cKLM-367A:  CN pin headers (PH)

  • This variation uses common pin headers instead of original male connectors. Pin headers are already mounted on the new PCB. Customer has only to use original and fully operative IC22 or get it from somewhere else. After installing of this part the cKLM-367A will work fine. Customer has to install this part by oneself.
  • Pin headers fit well into female connectors in Polysix.
  • CN PH variation benefits: not necessary to ship an old 367A to us. This reduces delivery time in comparison to variation „CN original“



cKLM-367A:  CN pin headers (PH)


cKLM-367A:  CN original

  • Customer must send an original 367A board (address is written in “Impressum”) to us! Don’t forget about tracking number!
  • Turnaround 1 or 2 working days starts after receiving of your package with an old 475/509A PCB!
  • We transplant original connectors and IC22 into a new cKLM-367A board. IC22 must be in working condition. Then we calibrate and test new board.
  • We ship finished cKLM-367A board to our customer
  • CN blank variation benefits: uses original stable connectors, customer shouldn’t care about de/soldering


cKLM-367A:  CN original


MCU replacement 8748-345

  • identical clone of an original mask 8048-345 MCU


MCUs 8748-345


Recommendations and hints when replacing 367A

Be sure female connectors on 367A (or even another boards), especially CN03, 06, 08 and 11, aren’t corroded. Individual connector’s contacts are visible from the side. All of them should have nice, silver metallic colour. If they are blue-green, white or dark grey they should be cleaned or replaced.

Be sure battery leak on 367A didn’t damage neighbouring boards (368/366/369/370).


Pricelist (in EUR) & ORDERING

Please, place an order via E-mail! Normally we response within 12 hours.