Is that an Intel 440ZX chipset ? Intel made many of the Micron boards and the DR737 was the IN440ZX OEM board, used in AST and some other computers AFAIK. BCM has the manual but does not mention that header but judging from the traces it goes to the ESS sound chip so is most likely a OEM specific Wavetable header. Side note: have a similar board but with ATI Rage video and Creative SB16 on board....

From what I can read it is: MBD00111-0222 which is this (the MBD # on the little white sticker near the video ram ):
http://web.archive.org/web/20020323174346/htt … ated+Components
Presto 8MB 2x Pentium II 440BX Micro ATX Motherboard with Integrated Components, MBD001111-02
Knowing that can lead to better info hopefully. Will do some digging when I get off work.

I love Toppers!

Horun wrote on 2021-02-16, 04:32:

Is that an Intel 440ZX chipset ? Intel made many of the Micron boards and the DR737 was the IN440ZX OEM board, used in AST and s […]
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Is that an Intel 440ZX chipset ? Intel made many of the Micron boards and the DR737 was the IN440ZX OEM board, used in AST and some other computers AFAIK. BCM has the manual but does not mention that header but judging from the traces it goes to the ESS sound chip so is most likely a OEM specific Wavetable header. Side note: have a similar board but with ATI Rage video and Creative SB16 on board....

From what I can read it is: MBD00111-0222 which is this (the MBD # on the little white sticker near the video ram ):
http://web.archive.org/web/20020323174346/htt … ated+Components
Presto 8MB 2x Pentium II 440BX Micro ATX Motherboard with Integrated Components, MBD001111-02
Knowing that can lead to better info hopefully. Will do some digging when I get off work.

More specifically, MBD001111-0222JPY

There's two chips here:

AGPset
FW82443BX
F942YC40
SL2VH
INTEL(M)(C)'98

PCIset
FW82371EB
L944IC10
SL37M
INTEL(M)(C)'98

The AGPset chip does say 443BX, and the Winbond chip does match with what you linked for I/O Chipset.

I took another look at the Maestro-2M on the board and tried to trace the pins to the Modem Header. What I could find are connections from pins 51 to 54, 59 to 62, 72, 73, 104 - 107. I think I was able to follow trace 29 to the bottom of the board and to the same connector... interestingly my chip has 144 pins while the manual for the Maestro-2 I found only has 100.
ftp://ftp.alsa-project.org/pub/manuals/ess/DSMaestro2.pdf
I can't for the life of me find a 2M manual. Either way, if what you're suggesting is true about the wavetable thing, that would be incredible. I kinda think it's just some fancy way for the modem to make its beep boop sounds directly to the same output as the rest of the sound though, but I'd love to be wrong.

Onboard ATI Rage and SB16 sounds really nice.

pete8475 wrote on 2021-02-16, 05:14:

I love Toppers!

\o/ Hopefully you're also a fan of their hawaiian?

Yours is the Maestro-2M

This looks like a proprietary implementation of what later became standardized as AMR, which had 46 pins, most of which related to AC97 data, although a handful also moved analog sound.

Yart wrote on 2021-02-16, 06:01:

\o/ Hopefully you're also a fan of their hawaiian?

I'll put it this way, it's pizza so I'll eat it but I wouldn't order it.

Maybe I'm boring but I usually just get a deluxe or pepperoni.

PC Hoarder Patrol wrote on 2021-02-16, 07:32:

Yours is the Maestro-2M

ESS Maestro-2M.pdf

Thank you so much for that!!

It seems like some of the pins are GPIO pins which are also for the ES2820, which seems to be for a 56k modem. The pins seem to be dual purpose though!

dionb wrote on 2021-02-16, 11:44:

This looks like a proprietary implementation of what later became standardized as AMR, which had 46 pins, most of which related to AC97 data, although a handful also moved analog sound.

Interesting! I took a look, and it has a lot to do with digital to analog audio conversion it seems. At least AMR doesn't seem to handle wavetabley stuff though. I was kinda hoping for more of just a re-wired PCI/ISA lines situation as I thought maybe this port could possibly be used for a project I've been kind of dreaming of. (Disabling FM in the Maestro via software and adding true OPL3 to the proprietary connector without taking up the motherboard's dedicated ISA slot.) I'm very much a hardware noob however and I'm not even sure how to begin reverse engineering a connector. Maybe it's time to learn!

pete8475 wrote on 2021-02-16, 11:47:

I'll put it this way, it's pizza so I'll eat it but I wouldn't order it.

Maybe I'm boring but I usually just get a deluxe or pepperoni.

Nothing boring about a deluxe! Especially with their house dip. 😁