Delete comment from: Ken Shirriff's blog
I have some experience with "house numbered" ICs. There were two kinds that I know of. The first kind are parts that are made under contract for a buyer, who specifies the number to be put on the part. These can be custom parts, or identical to parts sold on the market, but the numbering on the parts is specified by the customer. Data General did this to prevent third party service companies from being able to repair their computers. Most of the DG parts are off the shelf TTL, custom marked with DG numbers. I used to have a list, but in a fit of house-cleaning, threw it out...regrettably.
The second type of house numbered marking can appear the same as a commercial IC. I once worked on an electronic tachometer for an MG. The part inside was a TI part, with a part number one higher than a tachometer part listed in their catalog. I called the sales office, and they said it was a custom, in spite of the numbering. They then went to the engineer's desk and pulled a couple of parts from his desk drawer and sent them to me! As far as I know, the tach is still working.
Mar 25, 2020, 8:52:46 AM
Posted to Inside a Titan missile guidance computer