If the module is made for PLCC 286 systems it's easy to get it working in a PGA socket, but it is much more difficult to do it the other way around.
As far as I know Kingston made that upgrade in multiple versions, so without a picture it's difficult to say what it is.

This is the model in question:

http://www.ebay.com/itm/286-486-CPU-Upgrade-K … 5YAAOSwkZhWSjAQ

I haven't decided if this is a project worth pursuing just yet, even if I could get this to work I'm still limited to the 640k RAM in my system, and since I've only got an 8 bit expansion bus I'm not sure the worth of investing a ton of money into memory expansion boards.

It says in the ad:

Model SLC/50GAM only for IBM PS/2 Model 50 & IBM PS/2 Model 60 -> not usable with other 286 computers!

If you still want it, ask the seller. He knows what he sells.

snorg wrote:

This is the model in question:

http://www.ebay.com/itm/286-486-CPU-Upgrade-K … 5YAAOSwkZhWSjAQ

I haven't decided if this is a project worth pursuing just yet, even if I could get this to work I'm still limited to the 640k RAM in my system, and since I've only got an 8 bit expansion bus I'm not sure the worth of investing a ton of money into memory expansion boards.

At that price this upgrade isn't worth it and the prices on the NA eBay are even higher, may as well be crapping bricks sideways at those prices. 😵

That's way too much money, but it's PGA.

I figured it was probably PGA but haven't contacted the seller yet. And yes, I'd have a really hard time spending that kind of money for an upgrade chip that would be gimped by the bus and main memory.

I'd like to try creating a a simple clock-doubling circuit so I could drop a 16 or 20mhz 286 into my Tandy, I've been poking around on Dave Jones' EEVblog and he built something similar for a Tandy 1000sx and one of the NEC V20 chips, he wanted to have it switchable between 4.7 and 8 mhz. So it can't be too crazy hard to do something similar with a 286 in a Tandy 1000TX.

Just out of curiosity, what would a fair price for something like this be? Every 386 class upgrade chip I've seen on Ebay is running for well north of $100.

Hi, I have a Kingston SLC/Now! module for PGA 286 socket with IBM CPU 33G0275. I read it was intended for IBM PS/2 models. Did someone make it working on a generic 286 MB? I hope that electrically it should be compatible with every 286 but mine module seems to be KO.
I just repaired one 286 MB by Suntech with some coroded chipset PCB traces and I also replaced the PLCC CPU socket by PGA socket to be able to try this upgrade module. I tested the MB works fine with ceramic PGA CPU so I push in the upgrade module but it's dead, I have POST card attached but no codes come up. So I tried to replace the IBM CPU by intel 386SX CPU but it's still dead. There are no much more circuits, just some QuickLogic PLD/FPGA, socket for FPU and 50MHz oscillator that I checked it's working. So I suppose the problem is in QuickLogic chip that I cannot replace or some hidded connection problem in the PCB, that's a pitty...

Generally those PS/2 modules do work in normal 286 boards. I believe the only reason PS/2 versions were sold was so that the "dingus" was shaped in such a way that it wouldn't be obstructed by anything else on the motherboard or in the case. Even on standard boards, you can have a lot of installation issues depending on where the CPU socket is located. That's why companies like Evergreen even sold rotator sockets for their upgrade products.

No CPU upgrade is 100% compatible, so just because it doesn't work at all in that particular motherboard doesn't mean it's dead. I would definitely check in another board.
But, on the other hand it is very easy to plug these upgrades in the wrong way since the socket isn't keyed. That could certainly kill it.

Unfortuntelly I don't have other suitable 286MB (I have some with soldered onboard PLCC CPUs 16MHz from AMD and 20MHz from Harris).
The mechanical obstacles could be solved by elevating the upgrade board via stacking some PGA precise sockets together, in this case I don't have issues. You're right that as there's no key pin it's easy to fit it wrong, that probably happened to prev.owner...
BTW I found this 286 MB had wrong silkscreen on CPU socket that indicated pin 1 rotated 90deg on other corner it really should be. When I soldered the PGA socket to board I followed the silkscreen and aligned the socket along it. Then I looked at photo I took before mod and saw the CPU pin 1 was at different corner than silkscreen indicated so luckily didn't blow up my 286 CPU...

Sometimes you can use PGA sockets to stack the adapter over top of obstacles, but if the CPU socket is near the edge of the board the dingus might be obstructed by the edge of the case. This is a problem with my 5162 motherbaord. Or if the socket is too close to ISA slots, then stacking will not help you unblock them.

BTW, IBM 33G0275 is a 386 or 486DLC, right? Aren't those 3.3V?

You're right about the case/cards constraints...

There's not much references about 33G0275 but it should be 386SLC clocked at 25MHz (fxtal/2). The voltage regulator is not populated but Kingston also made 486DLC versions where it was probably used... That quicklogic chip is some FPGA with ~1000 gates, probably OTP?

I would have kept the 386SLC on there. It's a fairly rare CPU, plus it should have 8kb internal cache.
According to the model number, the SLC chips is probably a 33MHz part too.

I have one of those 286 to 486SLC2 Kingston modules as designed for a PS/2 50/50z, and I never managed to get it to work on a 'generic' 286 board. Regardless of the clock frequency you feed it, the board just sits there dead. Swap back in an original AMD/Harris 286 and it's happy again.

>megatron-uk
Hm, this is confusing, but are you sure that your Kingston module was working? I know it's hard to test it when don't have IBM PS/2...

>Anonymous Coward
I don't know if my IBM 386SLC is OK or dead. After a minute after power up it was quite warm but can hold a finger on it. The intel SX seems to me less warm. Only way I could test it would be take some SX MB (I should have one somewhere) and swap the chips with hot-air gun...

The SLC should run quite a bit warmer assuming they both work at 5V. The SLC die contains at least 8kb of cache. (should be 8kb for 386SLC and 16kb for 486SLC).

I wish i could find such an upgrade for my 286 Mainboard. It does not have an own oscillator for the CPU but only one 48mhz wich seems to be divided by 6.

Well, I grab one 386SX MB and swapped the CPU to test the IBM 386SLC and the MB was dead then, no POST. I swapped back original intel 386SX-20 and MB booted again. Also the ULSI FPU behaved weird. It was detected by sysinfo and HWinfo but Ndiags failed all FPU test and also Dos Navigator crashed at start up. When I removed FPU from the socket DN started normally. So I think it's evident that my SLC/Now upgrade module was damaged probably by placing at wrong position in socket. The QuickLogic FPGA is probably dead too and this chip I cannot replace, so this is dead end...

You can't swap IBM 386SLCs onto SX boards. They have extra control lines. I'm not even totally sure they are 100% pin compatible with 386SX even if you ignore the extra control lines. Did you compare the datasheets?

If you put the original 386SLC back onto the upgrade module, I'd be more than happy to take it off your hands.