The 386SX CPU was probably desoldered with hot air or just fell off at some point due to bad soldering. (You can still see the solder remnants on the landings.)

majestyk wrote on 2024-03-30, 06:01:

The 386SX CPU was probably desoldered with hot air or just fell off at some point due to bad soldering. (You can still see the solder remnants on the landings.)

It was not in the case, so it must have been desoldered at some point. I get that, it's just odd it was so carefully put back together. So it would be true that unlike the 487s, the Cyrix coprocessor is just a coprocessor?

Maybe someone needed a 386SX 25 MHz for upgrading another mainboard or as a replacement.
This seems to be yours:
https://theretroweb.com/motherboards/s/auva-c … mputer-npm16-a0

I'm pretty sure I have that motherboard at my father's house and it has an AMD 386 soldered onto it where yours is missing. I found it at Christmas last year and the board was totally annihilated by the Varta battery (worst I've ever seen). I don't know what to do with it, but I told him not to throw it away because the case is kind of cool and it has some parts that retro people overpay for 😁

See that M1217 chip? It's actually the CPU.

Well, not quite, rather, it's a 386SX core with the supporting chipset circuitry bolted on.

It seems like this motherboard could either have a standalone chipset and a real 386SX, or this ALi M1217 386SX+Chipset package.

So it could be this ? https://theretroweb.com/motherboards/s/unknow … 25-33-ali-m1217

or this https://theretroweb.com/motherboards/s/lucky- … -386sxa-ver-4-0 <This does seem to have a cpu.

and in the explanation for the m1217

The M6117 is basically an M1217 with an integrated Intel 386SX core. Large parts of the M6117 manual can be used for the M1217 as well

That kinda implies that the M1217 does not have an integrated 386sx core.

and all the other mainboards with that chipset which have photos available also contain a seperate cpu.

Can you take a good photo of the part where CPU is supposed to be ?

I have this exact same board somewhere, and I did a CPU upgrade on it sometime ago to turn it from 25 to 40MHz for some high end SX joy. Now if there was cache too...

Vynix wrote on 2024-03-31, 22:40:

See that M1217 chip? It's actually the CPU.

Well, not quite, rather, it's a 386SX core with the supporting chipset circuitry bolted on.

It seems like this motherboard could either have a standalone chipset and a real 386SX, or this ALi M1217 386SX+Chipset package.

You sure? The 1217 was available embedded with a 386 in the M6117 but under that part number I find no reference to embedded 386.

Yeah there is no cpu core in ALI m1217 afaik, my ECS 8517 board has the soldered 386sx40 as do the others I looked at.
added: https://cpushack.com/ULi.html = good explanation
added2: thanks for the mention, found the datasheet ! https://www.dmp.com.tw/app/webcamera/pdf/m6117d.pdf

Erm.. Now that you mention it.. I looked up and yes it's definitely the M6117.. Sorry, got the two part numbers swapped around.. To be fair, TRW lists this chip as "386SX/SLC single chip", and I misinterpreted that..

(note to self: read twice before posting)

This is a similar board (top photo is of a board I sold recently): https://theretroweb.com/motherboards/s/unknown-612-3035-001

The CPU can be upgraded to a TI486SXLC2-50 without any bodge wires to get the cache working.. solder it in and run the Cyrix utilty to turn on double clock mode... and done.

Maybe someone was thinking of doing this and desoldered the chip?

Horun wrote on 2024-04-01, 00:13:

Yeah there is no cpu core in ALI m1217 afaik, my ECS 8517 board has the soldered 386sx40 as do the others I looked at.
added: https://cpushack.com/ULi.html = good explanation
added2: thanks for the mention, found the datasheet ! https://www.dmp.com.tw/app/webcamera/pdf/m6117d.pdf

TYVM for the datasheet link it was something I was gonna be digging for for another system in near future.