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Square Chip Intel 286 ?

Z

ZOBEX

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Oct 7, 2009
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Maybe someone here had help ID an early 286 MB. It's in the general shape of an XT but a bit longer to handle the TTL. Won't fit an XT case I recall. The CPU is ceramic marked CG80286-8 from Intel, it's SQUARE ceramic chip. Board only takes 512kb but has 8 slots 6 are 16bt. Picked it up about 18 years ago and tossed it in the stack with the other stuff, keep wondering how long Intel made the square CPU chip. Anyone have any idea what this is ?? No maker names on it and the bios was generic so I replaced that with a later AMI. Does run and I had/have it running off a ST-412.

Dan
 
ZOBEX said:
Maybe someone here had help ID an early 286 MB. It's in the general shape of an XT but a bit longer to handle the TTL. Won't fit an XT case I recall. The CPU is ceramic marked CG80286-8 from Intel, it's SQUARE ceramic chip. Board only takes 512kb but has 8 slots 6 are 16bt. Picked it up about 18 years ago and tossed it in the stack with the other stuff, keep wondering how long Intel made the square CPU chip. Anyone have any idea what this is ?? No maker names on it and the bios was generic so I replaced that with a later AMI. Does run and I had/have it running off a ST-412.

Dan
Click to expand...

Do you got any high-res pictures?

However, it generally sounds like an PC/AT or an AT-Clone of some kind. I'm unable to tell whitch because I don't have enough information.
 
Can take some pics with my equally vintage digital camera. I am used to other forums but can pics be poste here ?? If not I will put up a link to them on the server.

Was wondering how long anyone used a SQUARE ceramic 286 chip. I started on computers with a Jolt 6502 when it was new. Never learned a lot but been through SWTP Rockwell AIM and a lot of other stuff over the years. But this is the first square 286 I have ever seen. Had to have it for that reason alone, besides it was free.

Dan


per said:
Do you got any high-res pictures?

However, it generally sounds like an PC/AT or an AT-Clone of some kind. I'm unable to tell whitch because I don't have enough information.
Click to expand...
 
ZOBEX said:
Can take some pics with my equally vintage digital camera. I am used to other forums but can pics be poste here ?? If not I will put up a link to them on the server.

Was wondering how long anyone used a SQUARE ceramic 286 chip. I started on computers with a Jolt 6502 when it was new. Never learned a lot but been through SWTP Rockwell AIM and a lot of other stuff over the years. But this is the first square 286 I have ever seen. Had to have it for that reason alone, besides it was free.

Dan
Click to expand...

A lot of the 286'ses were square cheramic, like in all the PC/AT's from IBM. There were also some cheramic ones with gold plating. I have not seen too many of those. There is a bunch more, but I don't really need to list all of them.
 
There are 2 types of square ceramic 80286 CPUs....

PGA: It has the pins on the bottom like a 386/486/Pentium chip does.

LCC: It has no pins on the bottom. Instead it has gold contacts directly on the chip's underside which mate to gold fingers in the socket. It 'floats' on those contacts.
 
Right it's the PGA, but is INTEL, says Intel '84 on the bottom line. I didn't know the early IBM were ceramic PGA. We tore apart a lot of XT's and junked them over the years, I have three setting here that were early IBM XT's we gutted and only used the case and power supply. Stuffed with generic XT's with V-20's and what ever else we scrounged up at the time. Anything faster than a 4.77. I will admit my first XT was a Jameco running 4.77 with a ripped IBM bios. Still running at 4.77 but a V-20, wow ! I thought it was big time when I installed not 2 but 4 360k 1/2 height floppies. I have another generic XT that has a transformer power supply with regulating transistors on the outside. Makes you wonder who came up with that one. I put it on this odd 286 motherboard.

Dan


per said:
It turns out that CG80286-8 actually is the PGA version of the 8MHz 80286 from AMD .
Click to expand...
 
I don't think anyone liked the LCC package. It was too easy to damage with most sockets (a complicated 2 piece affair). PGA was probably more expensive to fabricate, but Intel had pretty much committed to it with the 386.

PLCC has the advantage (along with PGA) that it can be soldered directly to the PC board if desired.
 
So what kind of socket is the one with flat "pins" or leads sticking out on all four sides then?
 
Chuck(G) said:
Are you talking about QFP? I didn't know that the 80286 came in QFP, just LCC, PLCC and PGA. PLCC is the type with J-shaped leads on all 4 sides.
Click to expand...

Well, kinda. It looks like QFP, except that pins were straight (so soldering would not be easy).
 
per said:
Do you got any high-res pictures?

However, it generally sounds like an PC/AT or an AT-Clone of some kind. I'm unable to tell whitch because I don't have enough information.
Click to expand...

OK so now I know what this weird 286MB is. Here is one on ebay now

390082518841

This guy says it is a pre-production evaluation MB. But I suspect mine is older than his as mine does not have any lable or silkscreen on it at all. Just a item control number on a paper lable. So it was worth hanging on to after all !!
 
ZOBEX said:
OK so now I know what this weird 286MB is. Here is one on ebay now

390082518841

This guy says it is a pre-production evaluation MB. But I suspect mine is older than his as mine does not have any lable or silkscreen on it at all. Just a item control number on a paper lable. So it was worth hanging on to after all !!
Click to expand...

If the layout is EXACTLY the same, and all the IC's are laid out in the exact same way as on the picture, what you got is an original IBM motherboard. Too bad your's doesn't got the original BIOS either.

I don't know too much about the AT to tell when yours are from, but look for datecodes on the different IC's. If sequences like "85xx" or "xx85" (where "xx" is a number between 1 and 52) occasionally reappear on several of the IC's (especially if they are from different vendors), then you know it is from around 1985.
 
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