This is a short story of the Roland MT32 Midi repair.

The MT32 MIDI interface had an annoying audio problem (you can listen to the audio files attached to this post).

It seemed like the classic problem of exhausted electrolytic capacitors, but instead it was due to the ROM ROLAND R15449121 (TC534000P) position IC37.

To replace the original ROM it would have been enough to use an OTP Eprom 27C040 which however i didn’t have in the laboratory so i used a FLASHROM AM29F040 by modifying some connections.

The filename of the file used to program the FLASHROM is “r15449121.ic37.bin” which you can find in the archive attached to this post.

Below is the documentation how to adapt the AM29F040 instead of a 27C040.

• Atmel AT27C040 – 4Mb (512K x 8) OTP, EPROM (32-pin Package)
• Amd AM29F040 – 4Mb (512K x 8) FLASHROM (32-pin Package)

Tie 29F040 WE (PIN 31) and connect to VCC (PIN 32)
Tie 29F040 A18 (PIN 1) and connect to PIN 31 on Socket or PCB

Monkey Island Audio difference before and after repair:

• Before the Repair (212)
• After the Repair (198)

Gallery:

Download: Roland MT32 (various OS and extra ROMs) (254)

source: Synth Eprom Dumps