You are about to find out... Chances are that there is some leftover stock. I doubt that nowadays anyone uses those outside of the retro community.

Do the acetone test on them once they arrive. Soak a cotton swab in acetone and rub it on top of the chip, if markings start to disappear or the swap gets stained the parts are remarked. If you're lucky the part had its date code "refreshed", if you're less lucky the part was originally say 20MHz that now has 25MHz rating.

Apparently the Boeing 737 MAX runs on a 286:

https://www.moonofalabama.org/2019/06/boeings … s-computer.html

😀

Many of these old CPUs are still produced and used today for embedded systems, like the Z80, the 6502, the 286, and the 486 (the 386 not, since it had bugs never fixed).

I've never bought CPUs from UTsource, but I have had remarked/fake STK modules and transistors from them.

derSammler wrote:

Many of these old CPUs are still produced and used today for embedded systems, like the Z80, the 6502, the 286, and the 486 (the 386 not, since it had bugs never fixed).

Do you have a link for the 286? Would love to see who still manufactures those.

EDIT: Found the 8086 from Intersil at Mouser: https://www.mouser.de/ProductDetail/Renesas-I … BwF98kPDA%3D%3D

And some WDC 6502 compatibles: https://www.mouser.de/Search/Refine?Ntk=P_Mar … m&Ntt=188298379

We will see. I suspect these may be remarked. I bought SAA-1099s from them some time ago and they work perfectly fine as CMS though.

Ive bought a lot of stuff from utsource in the past and had no issues with remarking and such, but they are still a large volume chinese seller, you can never be sure.

Got them yesterday. That was fast.

I need rest parts (oscillators, sockets etc) for one of my Suntacs and I will mod the sh** out of it. Hopefully it will work (for now it's missing OSCs and CPU looks overheated).

(sigh) (adds to watch list)

That actually looks like a real part. I'll see about getting one too 🤣

I think the CPUs themselves are not rare, but the boards designed to use them seem to be pretty uncommon. Even 20MHz 286 boards are not common compared to the 12 and 16MHz boards.

Do you need a different clock divider for the 25 MHz CPU? On my OPTI 386 board I can set the bus clock to CLKIN/2 to CLKIN/4, which allows me to set 8MHz for the ISA BUS. I would assume that a 16 MHz 286 board would divide the clock by 2 for the bus, but when modding to 25 MHz you would need to divide by 3?

root42 wrote:

Do you need a different clock divider for the 25 MHz CPU? On my OPTI 386 board I can set the bus clock to CLKIN/2 to CLKIN/4, which allows me to set 8MHz for the ISA BUS. I would assume that a 16 MHz 286 board would divide the clock by 2 for the bus, but when modding to 25 MHz you would need to divide by 3?

Motherboard has space for three oscillators, from what I was told:
OSC1 is for CPU
OSC2 is for FDC, if OSC1 is not 24MHz
OSC3 is for FPU running in async mode

I guess OSC2 maybe used for ISA BUS as well?

Anyway here is my motherboard which I want to mod:

And here is the mod I'm aiming for, I will probably leave the SIPP slots untouched though, as it's more 286-like, on the other hand SIMMs are available easier (I didn't decided yet).

root42 wrote:

On my OPTI 386 board I can set the bus clock to CLKIN/2 to CLKIN/4, which allows me to set 8MHz for the ISA BUS. I would assume that a 16 MHz 286 board would divide the clock by 2 for the bus, but when modding to 25 MHz you would need to divide by 3?

No, you would run ISA at 6.25 MHz in that case (/4), just like you would for an 12.5 MHz 286 (/2).

Re SIPP: you should rather mod your SIMMs to have pins. Leave the board as is, it's more valuable than some SIMMs.

EDIT: love the Suntac board. I simply love baby AT boards.

root42 wrote:

Re SIPP: you should rather mod your SIMMs to have pins. Leave the board as is, it's more valuable than some SIMMs.

The laziest way that leaves everything intact is to simply stick a pair of (desoldered, for example) SIMM slots into these SIPP sockets. Pairs of these tend to have the same distance as pairs of SIPP sockets. Though it doesn't feel a final solution it works for me quite well. And needs no alteration to the memory sticks, nor the board itself - only a donor board, of course. Or an other source of SIMM slots.

Anonymous Coward wrote:

I think the CPUs themselves are not rare, but the boards designed to use them seem to be pretty uncommon. Even 20MHz 286 boards are not common compared to the 12 and 16MHz boards.

20mhz and higher boards are pretty uncommon (I think I have one 20mhz unit). Those boards came out after everyone else was using a 386 or 486 of some kind.

if you look at a Promise VLB+ caching controller you will find a Harris 286-20 soldered on to it.

But can it run DOS…?