White ceramic PIA

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Last seen: 4 days 4 hours ago
Joined: Mar 7 2019 - 04:37
Posts: 3
White ceramic PIA

From the recycled american CNC machine tool 1979 production year, PIA chips were extracted.
Marking was missing, but one of the chips was replaced in 1981 with the original mc6821.
Manufacturer not known. In my assembled computer and this chip, the reset passes normally. Corresponding characters appear on the screen. I can not verify the work of the keyboard, because I have not collected it yet.

Who knows about this white chip. Since white ceramics except in the production of AMD I have not met. The Internet is also silent.



PS> I am going to sell a couple if there is a demand.

Last seen: 4 days 4 hours ago
Joined: Mar 7 2019 - 04:37
Posts: 3
Studying the data of the

Studying the data of the Internet, I managed to make about a theory about the appearance of this chip.
Chip xc6820 appeared in 1974, and released by motorola. But with the marking of motorola, I managed to find a photo dated to only 7511.

However, there is such a photo of the board:

and as we can see, two PIA white and purple chips are installed on it at the same time. The manufacturer's logo are missing, as well as the date 7420. So it became clear about when the chip appeared on the market.

The next step I needed to understand was who released my chip. Having found a photo gallery with a SIG 2513l chip released in 7322 by Signetics I saw the same manufacturer.

This is indicated by the shape of the body, and most importantly, the symbols "1" and a "dot" on the body. These symbols are not made of paint but are metal elements soldered to ceramics.
It turns out that my body is Signetics?

Probably at the early stage of the appearance of the 6820 chips, somewhere in the end of 1973 and the beginning of 1974, it was possible that the experiment chips were packaged by different manufacturers, or Motorola bought empty cases from third-party companies and then put its crystals.

And so I come to the conclusion that my chips are dated at least 1974, and are the very first ... we can say engineering samples.
Dispute me please, I really want to get to the bottom of the truth.

Last seen: 21 hours 22 min ago
Joined: May 30 2019 - 00:29
Posts: 11
AMI or American Microsystems

AMI or American Microsystems Inc seems to have made chips with designs from different companies (e.g. Motorola, Intel ++). In was quite common in the 70ties to license the design in order to increase production  (like for the MOS6502 which resulted in SY6502, R6502++).

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