Weird YMF704 wavetable module \ VOGONS

Weird YMF704 wavetable module

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First post, by stamasd

Posted on 2016-09-10, 02:00

stamasd Offline

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Location: Connecticut

Today while rummaging through some old boxes with odd parts I found this little guy.

I remember removing it from a computer that was getting scrapped from the place I worked at the time, sometime in 2001 or 2002. It was a PII-266 desktop, Micron brand but I don't remember the model number. I saw that it had this little daughterboard attached and decided to keep it. I actually wanted to keep the whole computer but wasn't able to. I remember that I wanted to figure our a way to use it in another computer but couldn't, and then it sat in that box for another 14 or 15 years until I found it today.

Here are pictures:

https://dl.dropboxusercontent.com/u/107843342/ymf704/1.jpg

https://dl.dropboxusercontent.com/u/107843342/ymf704/2.jpg

https://dl.dropboxusercontent.com/u/107843342/ymf704/3.jpg

It attached to the motherboard through two 6-pin connectors, one of which had a hole plugged. I can't find any information about it online.

I wonder if I can use it somehow...

(edit) I found this thread elsewhere, which didn't lead to anything... apart from that, no information. https://www.cemetech.net/forum/viewtopic.php?t=6961

Last edited by stamasd on 2016-09-10, 11:38. Edited 1 time in total.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 1 of 2, by Stiletto

Posted on 2016-09-10, 03:49

Stiletto Offline

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Rings a bell. IIRC the motherboard in Micron computers of that era had OPL3 integrated, but capable of "upgrading" to OPL4 via that little module you have. Or something like that. I believe I have a motherboard compatible with that module somewhere. I'll look into it.

"I see a little silhouette-o of a man, Scaramouche, Scaramouche, will you
do the Fandango!" - Queen

Stiletto

Reply 2 of 2, by stamasd

Posted on 2016-09-10, 16:45

stamasd Offline

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Rank: l33t
Posts: 2024
Joined: 2014-08-31, 19:59
Location: Connecticut

I have followed some of the signal traces, and it appears that the output from the OPL4 is transferred back to the motherboard digitally. The analog outputs are not connected. This makes me think that this module only works in conjunction with the motherboard sound chip, likely a YMF71x (YMF715 was common on motherboards from that era). I was hoping that it could be used as a standalone wavetable board with a simple pin adapter, but it looks like that isn't the case. It might be feasible to interface it to a sound card with YMF718/9 but complicated.

At this point, I don't think this can be used meaningfully except with the original motherboard, or one similar to it.

(I also can't figure out where the input connects to; based on placement of some vias, there are probably more traces under the chip but I can't follow those. In addition there is no clock source on the module, so the clock must be obtained from the motherboard).

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

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