AC wrote:

Sorry about the mistake in my post. I'm in mainland China and some of the photos must not be loading in properly. The only other board I saw in the thread was a 8086 board, which was too small to make out the details.

In the very first message in this thread there is a link: "80286?"

I contacted our "local 80286 dealer" and he offered me a cpu for 5 bucks.

I would like ask for your help in deciding which one to with based on the specifications of the board in my first post. I know next to nothing about that board but I trust you will have an idea on what cpu it can use....

cpu collection

He is willing to part with ONE and only one cpu of those of which he has more than one, so I have to choose wisely.

You can zoom in for a close-up. Thanks.

I would take the Harris 20. On the bottom left.

You also need to take a look at the crystal oscillator, which is close to the 287. It's frequency would be the double of that of the cpu. So if for example if it has 24.000 MHz written on it, the cpu is going to run at 12MHz. For a 16MHz cpu you need a 32MHz crystal, and for 20MHz cpu a 40MHz one.

edit : I also recommend getting the 20MHz Harris 286, for another reason. The 80C286 cpus(like this one) run a lot cooler than the older ones.

also, you can "upgrade" the oscillator to a 40mhz for a 20mhz board. there is no reason to NOT choose a 20 over anything else. a 20 chip will run fat and happy at 16 or whatever the board does.

luckybob wrote:

I would take the Harris 20. On the bottom left.

Unfortunately I cannot take the Harris 20 because I can only take on of a type, of which he has more than one. He has two Harris 16 so I assume that is the next best choice?

Markk wrote:

You also need to take a look at the crystal oscillator,

The oscillator is the shiny part below the 286 socket? To the left of the 287 fpu?

Dhall wrote:

Unfortunately I cannot take the Harris 20 because I can only take on of a type, of which he has more than one. He has two Harris […]
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luckybob wrote:

I would take the Harris 20. On the bottom left.

Unfortunately I cannot take the Harris 20 because I can only take on of a type, of which he has more than one. He has two Harris 16 so I assume that is the next best choice?

Markk wrote:

You also need to take a look at the crystal oscillator,

The oscillator is the shiny part below the 286 socket? To the left of the 287 fpu?

Ask anyway, he might not want it. If that fails ask for a 16. It really doesnt matter which one imho. I've been told harris made the best 286 chips but thats just speculation and rumor, I have no basis for that information, aside from the fact that harris is the only ones to make a 25mhz chip. At least its the only one i've seen.

as for the oscillator: http://i.imgur.com/XW0Z5.jpg
I edited your picture. you actually have 2 oscillators. #1 is likely to be 24,32,40,50 one of those. if its 40 you need to DEMAND the 20mhz harris.

#2 is likely the isa bus clock. I'd bet $5 it is 14.something mhz. if not let us know.

The two oscillators:

XTAL OSC PR-1100 32,000 Mhz, PRE 9122

PRE 14.31818 MHZ

Sooooo that means that I can go with the 16 Harris (he is unwilling to part with the 20) ?

Dhall wrote:

The two oscillators: […]
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The two oscillators:

XTAL OSC PR-1100 32,000 Mhz, PRE 9122

PRE 14.31818 MHZ

Sooooo that means that I can go with the 16 Harris (he is unwilling to part with the 20) ?

32mhz clock = 16mhz 286, so yes.

Thanks for all the help guys!

Because of you I will receive the following shipment next week for 27 dollars:

80486 mobo
8086 mobo
80286 mobo
7 ide controllers
80286 Harris 16 Mhz cpu
2x 386 mobos

I will be able to make better quality photos once I have these in my possession, if anyone is interested (though I presume you have seen all too many of these) just let me know. Thanks again!

Dhall wrote:

...(though I presume you have seen all too many of these)...

You presume too much sir! I for one love looking at hardware. I'm much more of a hardware man than software. Also, i'm jealous. you got a HELL of a deal on that hardware if even half of it works.