IBM AT "Engineering Prototype" ????

Engicoder

20 Nov 2015, 19:04

I recent purchased an IBM AT keyboard on eBay. Curiously, the seller mentioned in the description that it was an "engineering prototype". It seems very much like any other AT, so I asked him about it and I got this response:
In the early 80s, a local electronics company, Racal-Milgo, produced terminals for another local company, IBM. Racal then outsourced the keyboard manufacturing. To qualify, a prospective supplier had to demonstrate to Racal that their version of product operated correctly, was built to spec., etc. To this end, several suppliers submitted working prototypes built to Racal's specs, including the "IBM" logo, to Racal for evaluation. My friend was responsible for selecting the correct supplier. He had several of these in his office, destined for the trash, and offered one or more to me since a group of us were building PC clones. At that time, keyboards were very pricey so I was happy to get my hands on this beauty. I'm sure I would have gotten one for my buddy Ray, who may still have his, although one of his wives would have surely disposed of it, sadly.
This seems odd. He said that outside firms were making IBM keyboards to IBM specs with IBM logos. This doesn't sound right. Has anyone heard of such a thing?

The only odd think I noticed on the keyboard was the label on the back plate. The UL and SA seals are blacked out. The F is handwritten instead of stamped, but I think I have seen that before.
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terrycherry

20 Nov 2015, 19:35

The 84keys AT layout had the model F version but it was rare to see.

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seebart
Offtopicthority Instigator

20 Nov 2015, 19:52

More pictures please Engicoder.

Engicoder

20 Nov 2015, 20:42

Here you go: In all these pictures, a regular AT is on top and the claimed prototype is on the bottom.

The color of the bottom one is a bit more tan/brown and has a much duller (matte) finish.
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One difference, the back of the top is textured, but the back of the bottom is smooth.
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Top has two extra holes that are missing from bottom.
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Engicoder

20 Nov 2015, 21:10

Here is a angle shot that shows the texture / color difference of the top covers.
texture.jpg
texture.jpg (823.33 KiB) Viewed 1475 times

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seebart
Offtopicthority Instigator

20 Nov 2015, 22:54

Hmm very interesting, thanks for the pictures.

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bitslasher

26 Nov 2015, 01:17

Date codes on chips of the bottom board date it to late '88. The top board looks like an original run AT board. The bottom board looks like perhaps a remanufactured board. The plate has date codes consistent with original boards but the PCB has clearly had new components attached. The PROM on the "prototype" board is dated 3588 which means Intel fabricated the chip in August 1988, between the 21st and 28th. So there had to have been a little amount of time before it was programmed and installed in the board.

My theory is this could be an engineering sample from a company that IBM was looking to use for refurbishing their AT keyboards? IBM did this also with the original XT boards. The texture finish of the AT boards was sprayed on. So maybe they had "refinished" the case as well as rebuilt the PCB.

Just a theory...

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