We know what 1 is, I'm guessing that 2 is the gate array (is it surface-mounted?) and 3 is... something else, but not a ROM.
So, it certainly sounds like you were right in the first place about that stickered chip being the control ROM (I guess the marked numbers indicate the version). Is there anything stamped on the chip under the sticker?
wrote:I think I will sell it after getting a CM-64, don't know yet.
Would you consider a trade for a CM-64 perhaps? 😈 <little pinky in air>
the stamp of the stickered chip: LH57256-15 Sharp Japan 9204 5 DC
Yes the 2. chip is surface-mounted.
Ah, an EPROM. By the way, don't forget to replace the sticker to limit exposure to UV radiation.
Do you have access to an EPROM programmer for reading the chip?
I immediately replaced the sticker after I looked up the stamp of the ROM. So don't worry about the radiation. And by the way I think that a normal bulb light doesn't send out much UV light, cause the glass adsorbs most of the UV light.
Sorry I have no EPROM programmer, although I wanted to buy one at ebay. Maybe I have to send you the chip or the whole module, so you can read it out ect.. I also live in Germany.
Here's my take on the CM-500...
IC2 and IC3: Controller ROM and RAM for the CM-32L part. They aren't big enough to be sample ROMs. The writing on the top chip is obscured by the power switch "arm". It doesn't appear to say Roland, I'm guessing it's the RAM.
IC18: 1 megabyte ROM (27c080 type, although probably a mask ROM) replacing the two 512kb sample ROMs from the CM-32L design.
IC44: Reverb algorithm ROM.
The Mitsubishi M37702 is a microcontroller. The stickered EPROM is probably for driving it. My guess is that it's used to manage the four "ABCD" modes of the CM-500.
The Intel chip is the main controller CPU for the CM-32L part, replacing the large DIP in the original design.
(Edit: "main controller ROM" -> "main controller CPU")
Note that Talus - who's been extremely helpful in the development of Munt - actually knows what he's talking about. You can safely disregard my guesses. I don't even own an EPROM reader, and the thought of desoldering one of these precious chips makes me vaguely queasy.
Unfortunately it seems we're not so lucky as to have the control ROM we want socketed... And worse, the PCM ROM is surface-mounted. The contents of the latter are almost certainly identical to the waveforms in the CM-32L, though.
@ Kingguppy and Talus:
IC2 is labeled Malaysia 9142 HM62256LP-12 R4057886.
Thanks a lot about your help. Unfortuneately I won't desolder the device myself, cause I want to have a working CM-32L part of the device. I don't really need the Sound Canvas part, cause I also have a SC-55 at home.
