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In my regular eBay scavenge hunt of old PC gear, I found this:

Listed as “A HP Computer Circuit Board Spares Or Repair” Well… That’s enough to spark my interest. Straight away, you can see there is a bunch of 30-pin SIMM memory and a couple of industrial type connectors. Typically, these would be in a computer chassis connected to a back-plate or something. That itself was interesting. The support chips were all ‘Chips and Technologies’ support chips:

Chipset: P82C310C; P82A306; P82A303; P82C206; P82A304; P82C302; P82B305

So could be a little PC? Perhaps a processor board?

Well, indeed it is. Could not find any documentation for it, but the part is: HP D1430-60011 Processor Board

Taking the RAM off, I did some digging.

4x NEC MC-421000A9BB-80 1 MB

Blimey! That’s 4Mb 30-pin loveliness!

So far that’s a good return for the £5 I paid the whole thing… 🙂

Ok, let’s take the top off and have a look under the RF shield. The thing that draw me to this is the distinctive colour under the shield, just visible through the holes:

Anyone who has been round old tech have likely guessed already! Lets unscrew that sucker!

Well holy crap! That’s a 386 IC AND 387 maths Co-Pro! Result!

Intel A80386DX-20




I like these old chips from the days just before you had to worry about heat dissipation! Except for the low power 486 25MHz, many of the 486 chips started to have heat sinks. The venerable 20MHz 386 has no need of such frivolities.

So what is this for?

Some more digging I could find this System Board which I think is the back-plate for this PC:

HP D1470-60002 System Board

The processor board would sit vertically on the right-hand side and the rest as 8 and 16-bit ISA slots.

Not sure what the connector next to the keyboard socket is, but hey! I cannot find any documentation.

Not sure what to do with this. I could sell the bits for probably 20 times what I paid for it. Or use them for a basis of a future 386 build. Love the idea of the Co-Pro, even if the CPU is only 20MHz.

I would love to get one of these back-plate chassis, but they are rare it seems and housing them would be painful! If you know of a machine that has this configuration, please let me know. Perhaps these could be donor parts…

Well, that’s it for now. The old saying “There’s gold in them there hills!”