I found another 386DX/40 motherboard, which has a chipset labeled MX. Does anybody know if that's good or not? The only issue I came across, is that it has only one bank of simms, so you can place just 4 of them. On the other hand, it's the newest m/b of that type I've ever seen. It's tiny(it's barely longer than the isa slots) and it has a date code that says june 1995. It has onboard cache, but there are no socketed chips, and I really can't tell where is it.... By setting the two jumbers that officially says you can choose between 40 or 33MHz, I've managed to run it also at 25 and 16(!)MHz. And the strange thing is that the turbo makes it slower, without changing the actual speed. At 16MHz, with cache turned off, and turbo off, it is slightly slower than the VIC-20/12! I have a pic for you to see what it looks like :

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It has onboard cache, but there are no socketed chips, and I really can't tell where is it....

I believe some (maybe all?) of those Macronix chipsets have a small integrated cache. IIRC it's only something like 8K, but it's better than nothing.

I've always found those "mini" 386 boards interesting, but that's the first time I've seen one that uses a 386DX... most of 'em that size are based around the 386SX/486SLC.

MX? Try if Lemmings works in 'High Performance PC' mode. Might have an incompatible system timer (undocumented behaviour).

Old Thrashbarg wrote:

I believe some (maybe all?) of those Macronix chipsets have a small integrated cache. IIRC it's only something like 8K, but it's better than nothing.

You're absolutely right! I'm running speedsys on it, and it says 8kb L1 cache! However it performs well I think. The cpu scored 9.25 and the blue bar is beyond the 386DX-40 point.

What does this mean, please people? 1MB Write Per Bit Simm Module. This SIMM stick can be seen here, on ebay.

I'm looking for some more 1mb SIMMs, for the Contaq 386 mobo, as featured in DonutKing's original post. The ebay seller has lots of them, and they are cheap. I could buy 4. The SIMMs have 9 chips on them. I just wondered what the "Write Per Bit" wording meant. Thanks a lot for any advice.

> 1MB Write Per Bit Simm Module.

Can only guess it should express DRAM - opposed to SDRAM which is written in bursts.
Anyway these are the sort of modules you are looking for. Maybe you should look after modules where the access time is mentioned though. You wouldn't want the slow slugs with 100ns.

h-a-l-9000 wrote:

You wouldn't want the slow slugs with 100ns.

Hehe! Yes, you're right. I don't want any slugs in my machine. 😉 I could ask the seller what the speed is. Perhaps it's written on the chips, eg bla bla -100.

Um... hate to burst your bubble here, but those modules won't work in your 386 board. You need 30 pin SIMMs for that, and those aren't 30-pin SIMMs. Actually, I'm pretty sure those modules are proprietary and won't work in anything other than an AST machine.

Old Thrashbarg wrote:

Um... hate to burst your bubble here, but those modules won't work in your 386 board. You need 30 pin SIMMs for that, and those aren't 30-pin SIMMs. Actually, I'm pretty sure those modules are proprietary and won't work in anything other than an AST machine.

Phew, I didn't buy any! Thanks a lot for pointing that out! 😀

Some of my 386 bits have arrived, but I have made a mistake about the processor. I bought this one:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewIt … em=230394428942

Unfortunately, it's just a chip soldered to a hack-sawed piece of mobo. I can't actually use it. I need to get another processor. Can someone please verify that the following auction is OK to get - thanks a lot!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewIt … em=370301179337

retro games 100 wrote:

Unfortunately, it's just a chip soldered to a hack-sawed piece of mobo. I can't actually use it.

Wow that's rich...

The other auction looks fine.

Anyway what's the difference between the plastic and ceramic AMD cpus?

retro games 100 wrote:

Some of my 386 bits have arrived, but I have made a mistake about the processor. I bought this one: […]
Show full quote

Some of my 386 bits have arrived, but I have made a mistake about the processor. I bought this one:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewIt … em=230394428942

Unfortunately, it's just a chip soldered to a hack-sawed piece of mobo. I can't actually use it. I need to get another processor. Can someone please verify that the following auction is OK to get - thanks a lot!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewIt … em=370301179337

wow, I didn't see that. I also bought one as I thought it was a nice price.... 😳 That is not good at all. The seller should mention that it's a cut piece from a m/b, as there are also a lot of 386/40 cpus that are soldered on a small board that underneath it has pins to place it on a PGA socket, and are very similar if you look on them from up above.

Uhm the photo says all...

retro games 100 wrote:

Unfortunately, it's just a chip soldered to a hack-sawed piece of mobo.

What a lowlife scam -_-

And to think he may have gotten more for it selling it as a complete mobo.

He deliberately cut the cpu out to make it look as much as the original thing, then deliberately leave out the important bits.
Even sais he'll ship in antistatic packaging 😒 .

Edit: You have to be so careful with what you want to buy. I think everyone's made at least 1 bad purchase there.
I had a minor one, I was looking for 24pin 2 20pin ATX psu adapters as I'd bought a couple 350W FSP psu's new for a good price. But they have a 24pin connector which often won't fit on the (older) motherboards I had planned to use them on.
So I bought the adapters but didn't pay enough attention.
They were the right adapter, right, but the 12V wire was so ultra thin, theres no way I'm gonna risk using those adapters. With the current going through a thin wire, it'll probably melt or cause other kinds of havoc.

Another story, I once saw a veeery interesting chip for sale in the US. Noone was bidding on it and postage was just $10.
BUT...right before I bought the item, I double checked how much he'd ask for overseas shipping. $80 BUCKS!
$80 dollars for postage cost what normally would be more like $10 or less.

Another time I saw another veeery interesting chip for sale, the POD for Socket 4!!!
The seller seemed absolutely sure it was for Socket 4, so I asked him for a pic of the underside, received the pic, counted the pins and it was the MUCH more common (and thus, much cheaper) Socket 3 one.

But at least I haven't received any bricks yet 😜

I've got a confession to make. It's not easy saying this. I bought 10 of them. 😢 😢 😢 😢 😢 😢 😢 😢 😢 😢

I thought "get 10, and 3 won't work, so that leaves 7. I can do some mad experiments on 2 of them, which will leave 5. I can put 3 of them in to machines, and have 2 as back ups." Or something like that anyway.

Here's a photo of my waste paper basket.

He deliberately cut the cpu out to make it look as much as the original thing, then deliberately leave out the important bits.
Even sais he'll ship in antistatic packaging

I really don't see anything wrong with what he's doing... I mean, I'm sorry, but it's quite obvious from the picture that it's a cut-out chunk of board, and I see nothing in his description to represent it otherwise.

That's not to say that none of those sorts of sellers are scammers, but cutting out a piece of a board really isn't an uncommon thing for chip salvagers to do. It's a lot easier to ship QFP chips while they're still attached to something, since the pins are so delicate. Those sorts of outfits aim more at electronics hobbyists and chip collectors. The hobbyists can desolder the things for reuse, and the chip collectors usually don't want the full boards.

The seller's photo looked similar to the CPU in Donut King's original post. If the seller had included a photo of the underside of the CPU section (to show no pins!), then there would be no misunderstanding. It would be very obvious the chip had been hack-sawed away from a mobo, and not a chip to use in a CPU socket. I think the seller should have made the item photo more clear. I am not knowledgeable about 386 hardware.

Sorry to hear about your bad luck. I don't think it was an outright scam; maybe his description just needed a small amount more detail. Apparently, there's a market for scraps of this sort. There's just no such thing as being too careful when buying off the internet.

You know, seeing this post, for some reason, reminded me that I have an old 20mhz Intel 386 laying around somewhere. I know I have some 30-pin simms in a box somewhere as well. Maybe I should hunt down a motherboard.

retro games 100 wrote:

I've got a confession to make. It's not easy saying this. I bought 10 of them. 😢 😢 😢 😢 😢 😢 😢 😢 😢 😢

Dammid...

Well, let me put it this way...I didn't buy just one of those psu adapters either -_-
Well, perhaps you could still sell them on www.cpu-world.com?
Even if they're cut out of a pcb, if it's somekind of uncommon stepping, you could even get your money back 😉

www.cpu-world.com is full of chip collectors who'll desolder chips like these and put them up for display.
It's also a good source of chips as theres always sales going on.
You just have to let them know you want the chips intact, or at least so it looks to be functional, as they'll be selling them untested.
A plus is, it won't matter much for you if a chip has some scratches or part of the print is missing --> lower price ;D

Old Thrashbarg wrote:

I really don't see anything wrong with what he's doing... I mean, I'm sorry, but it's quite obvious from the picture that it's a cut-out chunk of board, and I see nothing in his description to represent it otherwise.

In RG100's defense, writing you'll be sending them in antistatic packaging suggests these are working units...