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First post, by weldum

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hi, i have some questions, some are a bit technical:
1> provided that i can find the right parts, should be possible to make a compatible cache board?
2> my M919 is version 3.2, it has 2 Simm72 slots and 4 Simm30 slots. what if i remove the Simm30 slots and fill the empty Simm72 places with 2 more slots? will it work? (the board has all the traces and the place for 4 simm72 slots, and 4 simm30 slots (these replace 2 simm72 slots)

thanks

Ohh, the humanity 😢
386SX 25-C3 800-P3 900-Atom 1.6-C-D 2.13-P4 2.26-P4HT 3.0-P-DC 1.6-AFX 2.6-FX 3.3

Reply 1 of 5, by Thermalwrong

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1. It's possible to make a cache board I think, just need to find the correct cache chips. Someone made detailed scans of the cache module here, but no-one's done this yet. It would require tracing out the PCB and making gerber/PCB design files to get some replacements made up.

2. Yeah it looks like it, the two versions of the board that I can see both look the same with the same components fitted around the slots. I think mine is the 4x 30-pin & 2x72-pin one but it's not a mod I'd try personally, you'd have to be fairly careful when desoldering but they're large through hole parts and I've swapped out 30-pin stuff on other PCBs easily enough before.

Reply 2 of 5, by weldum

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Thermalwrong wrote:

1. It's possible to make a cache board I think, just need to find the correct cache chips. Someone made detailed scans of the cache module here, but no-one's done this yet. It would require tracing out the PCB and making gerber/PCB design files to get some replacements made up.

from what i can see, it shouldn't be so hard, but it would be so much easier if i could get one of those boards (even if it doesn't work) to see how it's connected, also i should see the chipset pin configuration

Thermalwrong wrote:

2. Yeah it looks like it, the two versions of the board that I can see both look the same with the same components fitted around the slots. I think mine is the 4x 30-pin & 2x72-pin one but it's not a mod I'd try personally, you'd have to be fairly careful when desoldering but they're large through hole parts and I've swapped out 30-pin stuff on other PCBs easily enough before.

the thing is that i have a lot of EDO memory sticks, and these didn't work in my m919 (it seems that there are 2 revisions of the chipset) but few and low capacity FPM modules (4MB and 8MB)
I think that should be as simple as taking out the 4 simm30 slots and put the 2 extra simm72 slots, but i don't have any idea if that's enough, maybe i need to put some extra components

Ohh, the humanity 😢
386SX 25-C3 800-P3 900-Atom 1.6-C-D 2.13-P4 2.26-P4HT 3.0-P-DC 1.6-AFX 2.6-FX 3.3

Reply 3 of 5, by jerryt74332

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here is what i have, It works.

https://easyeda.com/jerryt74332/m919-cache-completed_copy

This is a very close copy of the original. I would like to make a 512 or 1024 next, but dont know how yet.

here is what i have, It works.

You can get your boards ordered from anywhere, or I do have on Ebay. You can search if interested.

Reply 4 of 5, by Deksor

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@weldum well these were much simpler times. I'm pretty sure it would work, just like I could add real cache to my PCChips m915i (which had soldered chips) and where the traces actually lead to somewhere (unlike the m919's "cache")
Also 72 and 30 pin fpm Simms work kind of the same way, so it shouldn't need extra circuitry. It's just that back then, these old simm sticks were probably cheaper than fpm sticks so it was a neat feature.

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Reply 5 of 5, by feipoa

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jerryt74332 wrote:

I would like to make a 512 or 1024 next, but dont know how yet.

Have you checked to ensure that there are pins on that SRAM slot for TAG address A15 and CACHE addresses A15 & A16? If not, then you will need to have some external wires soldered from your SRAM module to the motherboard.

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