KLM-509A 475B 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 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.

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. That means the functionality is the same.

cKLM-509A uses some hard to find parts. These are original connectors, IC1 (MCU 8049-217), IC30 (MCU 8049-337) and IC37 (reset IC MB3761). It is possible to transplant these parts from old 509A into the new PCB, but sometimes it is not possible. For example they are missing or they are faulty. For this case we offer replacement MCUs in another listing.

This listing consists of four variations, see below. The first variation uses original connectors, the other three variations use pin headers and FFC sockets (explanation below). Pin headers replace original connectors.

Two pictures in gallery show comparison between old (475B) and new (509A) PCB.

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3x different CONTROL BOARD VERSIONs
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 in this listing 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. See “VARIATION 2”.
  • In case FFCs are OK you can use them again. See “VARIATION 3&4”.

FOR SALE

  • 1x new cKLM-509A clone board (four variations are available)
  • cKLM-509A is a drop in replacement for the old, original KLM-509A/475 board
  • Regardless of a purchased variation you always get tested and fully working board with Korg’s factory sounds
  • MCU replacements on some photos aren’t part of this listing. These are in another listing available.

VARIATION 1: original connectors

  • Customer must send to us an original 475/509A board (address is written below in “business seller information”)
  • We transplant original connectors, IC1, IC30 and IC37 into a new cKLM-509A board. IC1, IC30 and IC37 must be in working condition. Extremely corroded connectors will be replaced by pin headers.
  • We ship finished cKLM-509A board to our customer
  • Variation’s 1 benefits: uses original stable connectors, customer shouldn’t care about de/soldering

509a_05

VARIATION 2: PH UNIVERSAL

  • 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 CN25B (supply connector), IC1, IC30 and IC37. 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%. Probability an old IC37 is working: >99%.
  • Pin headers fit well into female connectors in Poly-61.
  • Variation’s 2 benefits: not necessary to ship an old 509A to us. This reduces delivery time in comparison to variation 1, replaces old FFCs

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VARIATION 3: PH&FFC for KLM-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 CN25B (supply connector), IC1, IC30 and IC37. 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%. Probability an old IC37 is working: >99%.
  • Pin headers fit well into female connectors in Poly-61.
  • Variation’s 3 benefits: not necessary to ship an old 509A to us. This reduces delivery time in comparison to variation 1, works with original plugs and FFC

0101a

VARIATION 4: PH&FFC for KLM-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 CN25B (supply connector), IC1, IC30 and IC37. 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%. Probability an old IC37 is working: >99%.
  • Pin headers fit well into female connectors in Poly-61.
  • Variation’s 4 benefits: not necessary to ship an old 509A to us. This reduces delivery time in comparison to variation 1, works with original plugs and FFC

0202a

After purchasing of Variation 1 customer has to ship an old 509A board to us.
Use the address that is written below in “business seller information”.
We need a tracking number to track your parcel!
Turnaround 1 or 2 working days starts after receiving of your package with an old 475/509A PCB!

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.


 

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).

337384

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
  • One picture in gallery shows the places where to install MCUs on 475/509A board. This board is not a part of this listing and is available in another listing.

all
Recommendations and hints when replacing MCUs

Be sure battery leak on 475/509A didn’t damage sockets of MCUs. If yes, replace them.

 



Prices:

V1 – orig. connectors                    229€
V2 – pin headers uni                    195€
V3 – pin headers for 476 VB       195€
V4 – pin headers for 508 VB       195€
MCU 8749-384                               25€
MCU 8749-337                               25€

Payment via SEPA or paypal (+2…4%)
Shipping worldwide via German registered Mail incl. tracking number – 6,20€ (1 board).
Shipping throughout Germany via DHL Paket 2kg – 5,00€ (up to 4 boards)