Help identifying 386DX motherboard \ VOGONS

Help identifying 386DX motherboard

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First post, by nztdm

Posted on 2019-08-15, 23:00

nztdm Offline

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Joined: 2018-02-16, 22:12

Hello

Same ol same ol.. help me identify a 386 mobo with no branding.
I'll trawl through TH99 images later, but just checking if anyone knows.

FYI: It's a board I may purchase. I wanted a suped up 386. I see a desirable chipset. It has 33MHz CPU installed, but I only see a 50MHz oscillator, which I assume means it's running at 25MHz.
I see 64K of 25ns cache (8 x 8Kx8). I can get 32Kx8 12ns equivalents from mouser (will need to find the 22-pin TAG ones elsewhere).
Hopefully the chipset isn't binned for only 25MHz, and is unstable if I install an 80MHz oscillator.

Cheers
JD

Reply 1 of 3, by nztdm

Posted on 2019-08-15, 23:44

nztdm Offline

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Looks to be this: https://arvutimuuseum.ee/th99/m/M-O/30236.htm

And unfortunately not this: https://arvutimuuseum.ee/th99/m/E-H/30804.htm

Probably not suitable for 40MHz and lots of RAM/cache? It doesn't have the 28-pin sockets for 32Kx8 TAG SRAMs.

Reply 2 of 3, by ph4nt0m

Posted on 2019-08-16, 00:50

ph4nt0m Offline

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Mainboards of this kind with 22-pin tag chips support 64Kb of cache and 256Kb/1Mb SIMMs usually. It doesn't mean they are bad. The cache may work with better timings than 128Kb/256Kb on other boards. 16Mb of memory is still enough for most tasks.

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