On 2021-Sep-27, at 10:52 AM, Brent Hilpert via cctalk wrote: > On 2021-Sep-27, at 8:23 AM, Tom Hunter via cctalk wrote: >> While restoring and repairing a Data General Nova 2/10 I found a bad >> bipolar PROM on the CPU board. The PROM has open-collector outputs and is >> organized as 32 words by 8 bits. It appears that one of the open-collector >> driver transistors is faulty (but it could also be that a fuse has >> "healed"). >> >> The part is an Intersil IM5600CP, but these were also made by others, for >> example Signetics and Philips made the 82S23 and TI and NTE made the faster >> SN74S188N. Some vendors still sell these parts and there are even a few on >> Ebay. >> >> How do I program these PROMs? I found one somewhat obscure description of >> the algorithm in the NTE datasheet, but I suspect that each manufacturer >> had (somewhat) different algorithms. >> >> Is there an affordable commercial programmer out there which can program >> these PROMs? >> >> Is there a simple design out there which I could breadboard for a one-off >> programming job (maybe using an Arduino to control the programming >> sequence)?
> ... > Details of the 74S188 programming/burn algorithm is in the 1975 TI Memory > Databook for Design Engineers (available at bitsavers) (I expect the 188 is > the most likely type you'll find NOS today). The 82S23 programming algorithm is in the 1975 Signetics Bipolar Memories databook (also on bitsavers). Looks like it may be a little more complex than that for the 188.
