KLM-509A replacement board

About cKLM-509A replacement

Battery leak of an original NiCd battery in Korg Poly-61 synthesizer on control board KLM-509A/475 (shortly 509A/475) causes corrosion of vias, parts’ mounting holes, electric traces and electronic components (caps, ICs, transistors etc.). Metal parts are covered with white oxides and blue-green salts. Corroded metal can’t conduct anymore, so part of control board fails and it is not possible to program and play sounds.

Here is a list of some important 509A board’s tasks:

  • Provides Control Voltages for synthesizer blocks as DCO waveshaper, VCF, VCA
  • Is responsible for keyboard scanning
  • Generates pulse waveforms with its DCOs
  • Includes Tape Interface

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).

Another solution is to use a cloned 509A, that’s why the name cKLM-509A. It is almost an identical copy of original 509A 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 Poly-61 service manual.

cKLM-509A uses some hard to find parts. These are original connectors, IC1 (MCU 8049-217), IC30 (MCU 8049-337).
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, buy variations „blank“ or „original“ (see below).

Hard-to-find IC37 (reset IC MB3761) was replaced with a modern equivalent.

Six 509A variants are available (see below). These six variants only differ in what is mounted into connector pads.

  • CN original
  • CN pin headers
  • CN for VB 476
  • CN for VB 508
  • CN blank
  • CN straight NEW

 

Korg Poly-61 uses three different control board versions:

KLM-475 with small auxiliary board KLM-515 (early Poly-61 version)
This was the first control board version.

KLM-509A (improved Poly-61 version)
Later KLM-515 and KLM-475 were fitted together. In this way a new 509A control board was created. It is a full-blown replacement for old 475+515 boards.

KLM-509A with 8049-587 (IC1) and 8049-588 (IC30) MCUs (late Poly-61 version with factory MIDI)
This 509A board is identical to previous 509A board; it only uses upgraded 8049 MCUs (codes 587 and 588).
8049-587 and 8049-588 MCUs are especially designed for Poly-61 with factory MIDI implementation. But these MCUs also work fine in Poly-61 without factory MIDI.

CONCLUSION: The cKLM-509A can replace any version of control board!

 

2x different VOICE BOARD VERSIONs:

KLM-476 voice board with auxiliary board KLM-478 (early version)

KLM-508(A) (later version)
Later KLM-476 and KLM-478 were fitted together. In this way a new 508 voice board was created. It is a full-blown replacement for old 476+478 boards.

CONCLUSION: The cKLM-509A will work both with 476 and 508 voice boards!

 

FFC (flat flexible cable) connectors vs. PLUG connectors

  • Due to two different voice board revisions there are two types of CN34A connectors (located on control board). Old voice board 476 uses plug connector, new voice board 508 uses FFC.
  • There is another connector next to CN34A. It is a CN10A and it uses FFC, regardless of voice board revision.
  • FFC cables are often affected by battery leak so they must be replaced. Unfortunately it is hard to find a replacement for 6 (CN34A) and 18 (CN10A) pole FFC. In this case it is cheaper to make own FFC replacement.
  • In case FFCs are OK you can use them again. See “Variation CN for VB 476” and “Variation CN for VB 508”.

 

FOR SALE

  • 1x new cKLM-509A clone board (choose your variation)
  • cKLM-509A is a drop in replacement for the old, original KLM-509A/475 board
  • Regardless of a purchased variation all five variations come tested and with factory presets to the customer! No need to adjust/check the cKLM-509A board!
  • MCU replacements are from NEC or Intel

 

cKLM-509A:  CN original

  • Customer must send an original 475/509 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, IC1, IC30 into a new cKLM-509A board. IC1, IC30 must be in working condition. Extremely corroded connectors will be replaced by pin headers.
  • We ship new, finished cKLM-509A board to our customer
  • CN original variation benefits: uses original stable connectors, customer shouldn’t care about de/soldering

KLM-509_original_01

KLM-509_original_02

KLM-509_original_03

cKLM-509A:  CN original

 

cKLM-509A:  CN pin headers

  • This variation uses common pin headers (PH) instead of original male connectors. Pin headers are already mounted on the new PCB. Customer has to use own fully operative IC1 nad IC30. After installing of these parts the cKLM-509A will work fine. Customer has to install these parts by oneself.
  • Probability an old IC1/30 is working: >95%
  • Pin headers fit well into female connectors in Poly-61.
  • CN PH variation benefits: not necessary to ship an old 509A to us. This reduces delivery time in comparison to CN original variation. This variation replaces old FFCs

KLM-509_PH_01

KLM-509_PH_02

KLM-509_PH_03 KLM-509_PH_04

KLM-509_PH_05

cKLM-509A:  CN pin headers

 

cKLM-509A:  CN for VB 476

  • This variation uses common pin headers (PH) instead of most original male connectors. Pin headers are already mounted on the new PCB. Only on place of CN10A there is a socket for original FFC. That means this variation directly fits into Poly-61 with 476 voice board.
  • Customer has to use own fully operative  IC1 and IC30 After installing of these parts the cKLM-509A will work fine. Customer has to install these parts by oneself.
  • Probability an old IC1 & 30 is working: >95%.
  • Pin headers fit well into female connectors in Poly-61.
  • CN for VB 476 variation benefits: not necessary to ship an old 509A to us. This reduces delivery time in comparison to CN original variation. This variation works fine with original plugs and FFC.

KLM-509_VB-476_01

KLM-509_VB-476_02

KLM-509_VB-476_03

KLM-509_VB-476_04

cKLM-509A:  CN for VB 476

 

cKLM-509A:  CN for VB 508

  • This variation uses common pin headers (PH) instead of most original male connectors. Pin headers are already mounted on the new PCB. Only on place of CN10A and CN34A there are sockets for original FFCs. That means this variation directly fits into Poly-61 with 508 voice board.
  • Customer has to use own fully operative IC1 and IC30 After installing of these parts the cKLM-509A will work fine. Customer has to install these parts by oneself.
  • Probability an old IC1 & 30 is working: >95%.
  • Pin headers fit well into female connectors in Poly-61.
  • CN for VB 476 variation benefits: not necessary to ship an old 509A to us. This reduces delivery time in comparison to CN original variation. This variation works fine with original plugs and FFC.

KLM-509_VB-508_01

KLM-509_VB-508_02

KLM-509_VB-508_03

KLM-509_VB-508_04

cKLM-509A:  CN for VB 508

 

cKLM-509A:  CN blank

  • This variation has free CN pads. This means nothing is mounted into connector holes. Customer can  e.g. use the original male connectors from the old 475/509 board. Customer has also to use original and fully operative IC1 & IC30 or get it from somewhere else. After installing of these parts the cKLM-509A will work fine. Customer has to install male connectors and MCUs by oneself.
  • The CN blank variation is tested, calibrated and comes with factory sounds. We use special adapter to test this connector-less variation
  • CN blank variation benefits: not necessary to ship an old 475/509A to us. This reduces delivery time in comparison to variation „CN original“. Customer can use own, original connectors. Connector pads are free from solder

KLM-509_blank_01

KLM-509_blank_02

KLM-509_blank_03

cKLM-509A:  CN blank

cKLM-509A: CN straight new

  • This variation uses NEW and ORIGINAL straight male male connectors. Right angled connectors are Pin headers
  • Customer has to use own fully operative IC1 nad IC30. After installing of these parts the cKLM-509A will work fine. Customer has to install these parts by oneself.
  • Probability an old IC1/30 is working: >95%
  • Right angled Pin headers fit great into female connectors in Poly-61.
  • CN Straight new variation benefits: 1:1 original straight connectors, that make a perfect connection with its female counterpart

KLM-509A_CN-new_1

KLM-509A_CN-new_2

KLM-509A_CN-new_3

 

Recommendations and hints when replacing 509A

Be sure female connectors on 475/509A (or even other boards) 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 509A didn’t damage neighbouring boards.


 

Replacement male connectors for KLM-509A board (and other boards) + replacement contacts

  • For sale are original 6 and 8 pin straight connectors for KLM-509A / 475B board or other boards in Poly-61 (and other Korg synths, e.g. Monopoly)
  • These parts are NEW
  • Making 14 pin connector: 14 pin = 1x 6 pin and 1x 8 pin
  • Making 18 pin connector: 18 pin = 3x 6 pin
  • Making 12 pin connector: 12 pin = 2x 6 pin

 

  • Replacement contacts can be used to replace old, corroded contacts. Connector housing can be reused after cleaning. In combination with replacement male connectors, almost all connector junctions can be repaired!

jst_male-8-pin

jst_male-6-pin

jst_male-side

Replacement 6 and 8 pole connectors

jst_contacts_2

jst_contacts_1

Replacement contacts


 

About Poly-61 MCU replacement

Battery leak of an original NiCd battery in Korg Poly-61 synthesizer on control board KLM-509A/475 (shortly 509A/475) 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 control board fails and it is not possible to program and play sounds.

Sometimes aggressive battery leak affects IC1 and IC30 on control board and they stop to work. These ICs are microcontrollers (or shortly MCU) that are heart of control board.

There are two MCUs on 475/509 control board. One is responsible for Key Assigner (suffixes 217, 384 and 587) the other one for Programmer section (suffixes 337 and 588).

 

337

384

 

Key Assigner MCUs

  • 8049-217 – first version (also used in Korg Polysix on KLM-366(A/B) board)
  • 8049-384 – second, improved version, will work instead of 8049-217
  • 8049-587 – usually installed in Poly-61M with factory MIDI

 

Programmer MCUs

  • 8049-337 – installed in all Poly-61 synthesizers without factory MIDI
  • 8049-588 – usually installed in Poly-61M with factory MIDI

 

FOR SALE

  • 1x 8749-384 or 337 replacement
  • These MCUs are a drop in replacements for old/original MCUs
  • Manufacturer NEC or Intel

 

all

The picture shows where to install 384/337 MCUs

 


Pricelist (in EUR) & ORDERING

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

509_poly61_prices

 

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