PDA

View Full Version : IBM PC 5170 and 80286/4?



romanon
June 5th, 2017, 08:44 AM
Hello.

Was this processor ever used in IBM PC AT?

According to Wikipedia


80286 - 6 MHz (4 MHz for a short time) to 25 MHz


The 80286 was employed for the IBM PC/AT

38947


Roman

Chuck(G)
June 5th, 2017, 09:07 AM
Right from the pre-release steppings, our 80286s were all 6MHz CLCC parts and US manufacture.

The only -4 parts I've seen reported were fabbed in Malaysia and had '84 date codes. I suspect they were de-rated -6 parts that didn't pass 6MHz QA. There are at least 5 different ones reported on the 'web.

Anonymous Coward
June 5th, 2017, 03:58 PM
All of your 6MHz parts were CLCC? I usually see those as 10, 12 and 16MHz parts. Almost all the 6MHz parts I've seen have been PGA.

Chuck(G)
June 5th, 2017, 04:53 PM
Nope--that's the way that Intel delivered even the pre-release steppings. I've still got a couple of the 6MHz 80286 ones. They also came that way in the early Faraday and Olivetti 286 boards. Personally, I hate those sockets.

80186 was initially shipped that way also--just like the illustration at the top post.

Fortunately for everyone, the socket lead pattern is the same for both. So if you wanted to go PGA vs. CLCC, it's just a matter of unsoldering one socket and popping in another.

Anonymous Coward
June 5th, 2017, 07:40 PM
Other than being somewhat annoying to attach a heat sink to, what are other disadvantages or annoyances of clcc? I've always been a bit fascinated in that package type as it seemed very futuristic for the time, and it's very interesting that modern cpus use very similar sockets.

Chuck(G)
June 5th, 2017, 09:06 PM
Well, it always seemed pretty easy to me to damage a chip by leveraging it in with the spring-loaded top plate and not getting the chip seated correctly--it's a 2-handed operation. It's difficult to attach any sort of heatsink, although one of the boards I have uses a little "chimney" attached to the top plate. For low-density plastic, I much prefer PLCC; for ceramic, PGA is pretty good.