Great news!!!!
I was lucky to find some NOS AM27C512 uv eproms, but ofcourse eeproms are prefered! thanks for the info Carlos!

No problem!!

Happy to be helpful!

Hi carlostex,

Would you be able to give us a quick rundown of the differences between the control ROMs and how to tell which version a particular CM-32L unit has?

Thanks

The 1.02 Rom solves a cliking issue:

http://queststudios.com/smf/index.php?topic=3564.0

To check, one needs to open his/her CM-32L and check if the unit has a socketed ROM or a soldered mask ROM on board. An EPROM on a Socket means you have Control ROM 1.00. The sticker on the EPROM has numbers that indicate exactly its ROM version.

Check this:

http://www.youtube.com/watch?v=5NUQpAZeAdo#

easiest way is testing with TAKEGO.MID as described, I am attaching it for convenience

bjt wrote:

Hi carlostex,

Would you be able to give us a quick rundown of the differences between the control ROMs and how to tell which version a particular CM-32L unit has?

Thanks

Alternatively you can send a special MIDI command the unit and it will send back the ROM version 😀

I believe I also covered this in my video. But not 100% sure.

The serial number is also a good indicator. Again watch my video as I have forgotten all the details already 😊

I've done this to my LAPC-I as well - works fine.

I looked to see if someone has tried doing a mt-32 to cm-32l rom upgrade, didn't find, but there are several mods.

http://www.oldcrows.net/~patchell/mt32/mt32.html
http://www.houseofsynth.com/roland-mt-32-hard … e-sound-quality

ih8registrations wrote:

I looked to see if someone has tried doing a mt-32 to cm-32l rom upgrade, didn't find, but there are several mods.

http://www.oldcrows.net/~patchell/mt32/mt32.html
http://www.houseofsynth.com/roland-mt-32-hard … e-sound-quality

I believe such a mod may be possible to turn a late MT-32 (with a headphone jack) into a CM-32L. It would require replacing the MT-32 Control ROM with the CM-32L Control ROM and the MT-32 PCM ROMs with CM-32L PCM ROMs. EPROMs may be used. I am not 100% sure, but I believe the late MT-32 only has one PCM ROM. The CM-32L increases the PCM ROM size from 512KB to 1MB, but uses two ROMs. The CM-64 schematic shows how the chip enables work with the LA32 chip, and you would need to replicate that circuit and piggyback the two ROMs.

Great Hierophant wrote:

ih8registrations wrote:

I looked to see if someone has tried doing a mt-32 to cm-32l rom upgrade, didn't find, but there are several mods.

http://www.oldcrows.net/~patchell/mt32/mt32.html
http://www.houseofsynth.com/roland-mt-32-hard … e-sound-quality

I believe such a mod may be possible to turn a late MT-32 (with a headphone jack) into a CM-32L. It would require replacing the MT-32 Control ROM with the CM-32L Control ROM and the MT-32 PCM ROMs with CM-32L PCM ROMs. EPROMs may be used. I am not 100% sure, but I believe the late MT-32 only has one PCM ROM. The CM-32L increases the PCM ROM size from 512KB to 1MB, but uses two ROMs. The CM-64 schematic shows how the chip enables work with the LA32 chip, and you would need to replicate that circuit and piggyback the two ROMs.

I was thinking a good mod would be to connect a microcontroller with ram/sdhc/usb to the rom sockets to allow switching rom sets on the fly,

Getting fancy would be to make a midi tsr that sends midi via the microcontroller usb at faster rate than midi. That's the thing with external modules, slow.