Some help to identify those ICs from 1973-74

[Jaginus]

Hi IC gurus,
A few months ago I bid on some boards that according to the seller belong to ICL systems. As part of the joy of the end of the year, I did some repairing and revisit some purchases. Truth is that I am struggling to find out any information on those ICs. Running out of ideas and sites to look at, I prepared a kind of "collage" with the ICs to help in the identification. Brands are General Instuments, Fairchild and one I've never seen before: logo is an "A" over "MI" (guess it has nothing to do with American Megatrends Inc.).
I also included pictures of a couple of the boards for context (and for the beauty of it too).
Anyone so kind to tell me a place where I could find something about those ICs ???. They are dated 73-74.
Any help would be much appreciated.

 

[durgadas311]

Found this at https://www.computerhistory.org/siliconengine/companies/:

American Micro Systems (AMI)

American Micro Systems, Inc. was founded in 1966 in Santa Clara, California by
four Philco-Ford Microelectronics (formerly General Microelectronics) employees
(H. Bobb, V. Peterson, W. Vallandighan, W. Wheeler) to produce MOS integrated circuits.
In the 1970s AMI was a leading supplier of custom circuits (ASICs). Today, known as
AMI Semiconductor (AMIS), the company is headquartered in Pocatello, Idaho and focuses
on integrated mixed-signal products. Fiscal year 2006 revenue was $606 million.

I suspect the "417xxx" numbers are OEM part numbers, similar to what Heathkit did with their electronics (trying to figure out a Heathkit circuit is a real pain, until you have the magic decoder for their part numbers to industry-standard numbers (e.g. 443-1 means SN7400N)). I suspect this OEM was buying enough that they had the IC manufacturers stamp custom part numbers on their chips. Finding the "real" IC numbers may be difficult, unless you know who made the machine and can get the repair manuals.

 

[Chuck(G)]

I'm sure that these are all house numbers; given that they're obviously LSI, they may also be PMOS or some such uncommon logic. I recall that Fairchild did a lot of custom orders during this period (e.g. the STAR register file).

It might be useful to identify these as belonging to some specific piece of equipment.

 

[Jaginus]

Thank you for such fast answers !!!. If they are custom, Iĺl be screw trying to find any reference. Perhaps with patience I could find + and -, put some current and observe the outputs, but it will be crazy anyway.

 

[Jaginus]

Found this at https://www.computerhistory.org/siliconengine/companies/:

American Micro Systems (AMI)

American Micro Systems, Inc. was founded in 1966 in Santa Clara, California by
four Philco-Ford Microelectronics (formerly General Microelectronics) employees
(H. Bobb, V. Peterson, W. Vallandighan, W. Wheeler) to produce MOS integrated circuits.
In the 1970s AMI was a leading supplier of custom circuits (ASICs). Today, known as
AMI Semiconductor (AMIS), the company is headquartered in Pocatello, Idaho and focuses
on integrated mixed-signal products. Fiscal year 2006 revenue was $606 million.

I suspect the "417xxx" numbers are OEM part numbers, similar to what Heathkit did with their electronics (trying to figure out a Heathkit circuit is a real pain, until you have the magic decoder for their part numbers to industry-standard numbers (e.g. 443-1 means SN7400N)). I suspect this OEM was buying enough that they had the IC manufacturers stamp custom part numbers on their chips. Finding the "real" IC numbers may be difficult, unless you know who made the machine and can get the repair manuals.

Thanks Doug. Will try to find the "ICL" path and find some more docs if I have the luck, as it is not that obvious.