Not the answer to your question, but you can buy a pre-programmed ROM set on one the usual marketplaces.

darry wrote on 2020-05-02, 15:37:

Not the answer to your question, but you can buy a pre-programmed ROM set on one the usual marketplaces.

Yes I've seen that. But I don't like paying someone else for something I can do myself. I have a couple EPROM burners. So I'm confidant I can do it all myself, if I had the files and the right EPROMs.

In case anybody is curious, the correct EPROM ICs are 27c256. Two are required for IC26 & IC27.

I wont link to the ROM images as I think it is against vogons rules. But they are out there.

it makes me wonder what the changes where in the 1.07 version , I don't think they are documented?

They are documented in the MT-32 Service Notes. I am not typing everything up, only so far:

MT-32 Service Notes, 2nd Edition wrote:

v1.05 to v1.06: To reset Bender Control change in rhythm section when All Parameter Reset (MIDI) is received or Active Sensing is not recognized. To not change displays even Display Change exclusive MIDI message is recognized unless the current mode is Master Volume input mode (e.g. Power-up default).

v1.06 to v1.07: For stable program operation. If the program won't start after replacing SRAM IC29 or 31, use ROMs of Ver. 1.07.

All (sic).

Here are the firmware version notes I found at https://en.wikipedia.org/wiki/User:Lord_Nightmare

11.04 - unknown, initial release?
21.05 - Volume knob changes are now interpolated as opposed to directly applied to the data, allowing for much smoother volume changes when using the knob
31.06 - Rhythm selection Bender Control is now reset when MIDI All parameter reset is recieved, and when MT-32 Active Sensing is not received. Displays will not change, even when a Display Change exclusive MIDI message is recognized, unless the current mode is Master Volume input mode (e.g. Power-up default)
41.07 - Fixes a bug related to specific values in uninitialized sram on startup causing the unit to act bizarre.
52.04 - Unknown (possibly the first 2.x mt-32 rom. contains changes boosting the level of the la32 chip to de-necessitate the 14-bit hardware dac-hack, and changes related to the demo mode expanded rom, and the changed hookup of the volume knob, and possibly other changes related to the MT-32 2.x pcb)
62.05 - Unknown
72.06 - Unknown
82.07 - Unknown

thanks for the infos... curiosity gone 🤣

I see that the changes beyond version 2.00 are still not transcribed. Well.
v1.04 to v1.05: Change the taper of VOLUME control by changing the programs in the ROMs. Result: Smoother volume change in response to VOLUME setting change.
v1.05 to v1.06: To reset Bender Control change in rhythm section when All Parameter Reset (MIDI) is received or Active Sensing is not recognized. To not change displays even Display Change exclusive MIDI message is recognized unless the current mode is Master Volume input mode (e.g. Power-up default).
v1.06 to v1.07:For stable program operation. If the program won't start after replacing SRAM IC29 or 31, use ROMs of Ver. 1.07.
v1.07 to v2.00:

1. Default Assign Mode is now Multi-Assign.
2. Part priority has been changed from R,1,2,3,4,5,6,7,8 to 1,2,3,4,5,6,7,8,R.
3. Tone group [r] rhythm preset tones 31 to 60 set to repeat tones 1 to 30.

v2.01 to v2.03: Not released.
v2.00 to v2.04: The following bugs and symptoms were fixed:
Bugs (newly introduced in Version 2.00, unrelated to Version 1.**):

1. When requesting data, an amount of data exceeding the specified range may be returned.
2. When requesting data from an undefined address, nonsensical data might be output.
3. When receiving RQD with non-matching DEVICE-ID, only EOD is sent.
4. When trying to change several MIDI channels with a single exclusive message, only the first part is changed. However, all might seem to have changed when requesting data.
5. The RPC (Registered Parameter Control) number to change the bender range is 2 (correct would be 0).
6. Sustaining rhythm part sounds from keys #88+ use the output level of keys #24+ (88←24, 89←25, 90←26, ... MT-32 officially does not support keys #88+).
7. Directly after power-up, Data Set (DT1/DAT) to the timbre temporary area accessible at UNIT# (Addr 04 XX XX) is not accepted.

Symptoms:

1. Third party song data may exhibit missing sounds (due to Version 2.00 change item A described above).
2. When booting Come On Music’s RCM-PC98, the message “data read error, please check connections” is displayed, and no data can be gathered from the MT-32 (due to bug A described above).
3. In Dynaware’s Ballad, timbre editing is not possible. Generally, with third-party song data sending timbre data as exclusive messages, upon sending timbre data as an exclusive message, it is possible that the timbre data does not change (due to bug G described above).

Changes:

1. Reversed Version 2.00’s change items A,B,C (described above) to Version 1.**’s behavior. Specifically,
   • Default Assign Mode is Single-Assign again.
   • Part priority changed from 1,2,3,4,5,6,7,8,R back to R,1,2,3,4,5,6,7,8.
   • Tone group [r] rhythm presets 31 to 60+ are OFF again.
2. With ring-only structures, when the ring [modulation] cannot use any remaining partials, no sound is made. (in Versions 1.00-1.08 and 2.00, because ring [modulation] cannot be used, it sounds as if a different sound is played.)
3. During the Attack Phase, when changing the key shift, the Attack will cease by itself (in Versions. 1.00-1.08 and 2.00, the sound did not stop).

v2.04 to v2.05: Version 2.05 cures the following problems:

• When a MT-32 is playing the tune of "ISM" library "EL-106-1", the MT-32 may stop sounding at the 10th measure of the tune wrongly. In this case, you must turn the power off once and on again to return to the normal operation.

v2.05 to v2.06: Version 2.06 cures the following problems:

• When a MT-32 receives "volume" message of "control change" at time intervals of shorter than several mm seconds, the received "volume" value may be wrong. (It has been confirmed that this phenomenon occurs by "volume" message from FC-100MK2 or S-50.)
• When a MT-32 is playing many notes with a tone that consists of structure 11-14, the MT-32 may hang up. (There is no tone in that consists of structure 11-14 in the MT-32 preset tone. Therefore this symptom will occur only when a software that has tone edit function is used with the MT-32 and a tone that consists of structure 11-14 is used.)
• When 8 part data are set to the patch temporary area of the MT-32 via MIDI exclusive at a time, the part 2-8 data and bender data will not change correctly. (Another data will change correctly.)

v2.06 to v2.07: Version 2.07 cures the following problems:

• When a MT-32 receives "8X KK VV" (Note Off) in Overflow Assign Mode, the MT-32 wrongly transmits "9K KK VV" (Note On) instead of "8X KK VV" (Note Off). Example: When MT-32 "B" (MIDI IN) is connected to QX-3 (MIDI OUT) via MT-32 "A" in Overflow Mode, and the MT-32 "B" receives some overflowed "Note Off" messages which cannot be played in the MT-32 "A", the MT-32 "B" will output sound wrongly in spite of "Note Off" message.
• With regard to 2-data-byte-message, when "FC" is inserted between the first-data-byte and the second-data-byte, the status and the first-data-byte will become indefinite. Example: When MT-32 is connected with QX-5, the output may remain sounding wrongly when it should stop.

Sources:

• MT-32 Service Notes, Second Edition (Information on versions 1.04-1.07)
• MT-32 Service Notes, Third Edition (Information on versions 2.00-2.04)
• MT-32 Service Information No. 100463A, 1990-07-23 (Information on versions 2.05-2.07)

I also have perused the MT-32 Service Notes, First Edition, but they do not contain any information on ROM version changes.

Are all hw versions compatible with post 1.x firmware ?

Thank you NewRisingSun. It is great to get all this info in one place.

darry wrote:

Are all hw versions compatible with post 1.x firmware ?

No, v1.0x firmware versions can only be used with the old-type circuit boards (without headphone socket), and v2.0x firmware versions can only be used with new-type circuit boards (with headphone socket).

darry wrote on 2020-05-03, 12:44:

Are all hw versions compatible with post 1.x firmware ?

I think firmware 2.xx are only compatible with the rare second version of the MT-32 -- the one with the headphone jack on the rear.

And because it was so much fun, the same procedure for the CM-32L:

v1.00 to v1.01: Version 1.01 cures the following problems:

• In Patch Temporary Area, when MIDI Exclusive Data (8 different parts and a rhythm part) is sent, "tone" and "bender range" to be varied do not change.
• With 2-byte-message, when "FC"H is inserted between the first byte and the second byte, the status and the first byte become indefinite.

Improvement:

• Some noise originated when PCM partial was truncated. The noise is reduced.

v1.01 to v1.02: Version 1.02 cures the following problems

• Sometimes no sound was output at power on. (At power on, the unit recognized that the value of master volume was "0", so audio signal could not pass through "VCA" circuit. Note: Concerning all the unit with ver. 1.01, some hardware (CR value change) modifications have been carried out to cure this problem instead of the software revision to ver. 1.02. Refer to Service Info No. 100420 for the hardware modification.

Source:

• CM-32L Service Information No. 100421A, Feb. 14 1990.

My comment:
The CM-32L is subject to the same bug described in MT-32's v2.07 where the MIDI Command 8x variant of "Note Off" is relaid as "Note On" in Overflow Assign Mode. I don't know which CM-32L ROM version cures that problem, if any, since the feature is undocumented on the CM-32L.

NewRisingSun wrote on 2020-05-03, 12:57:

And because it was so much fun, the same procedure for the CM-32L. . .

Thank you again NewRisingSun. Upgrading the firmware in my CM-32L is my next project after the MT-32.

Can you confirm the CM-32L firmware just on IC6 (27c512)? As opposed to the MT-32 where it is split between multiple ICs.

From CM-32L Service Information No. 100421A:

"PROGRAM ROM:
CM-32L: (IC6 ON MAIN BOARD)
CM-64: (IC6 ON LA BOARD)
Mask ROM LH53141J -- (PN.1520921401) -- THE LATEST VER.102"

NewRisingSun wrote on 2020-05-03, 13:22:

From MT-32 Service Information No. 100421A: […]
Show full quote

From MT-32 Service Information No. 100421A:

"PROGRAM ROM:
CM-32L: (IC6 ON MAIN BOARD)
CM-64: (IC6 ON LA BOARD)
Mask ROM LH53141J -- (PN.1520921401) -- THE LATEST VER.102"

Outstanding!

May you please tell me what is it with the rom versions? Are they important for gaming for solving bugs? I checked my Roland MT32 (it is the old unit) and it has the version 1.07.

thank you in advance.

i had a rom revision 1.05 and burned 1.07 and were buggy ,on games like monkey island some sound parts didn+t play ,maybe could be 25ns timming on eproms maybe...

Is there any way I can find those MT-32 Roms for Munt? Mostly the v2.04. I can't find it any where...