As part of my quest to make a MK14 replica, I have encountered the problem of the PROMS used by Science of Cambridge, the 74S571. It appears that they were made by a number of manufacturers, and as proms being read they are drop-in compatible. However actually programming them is a different matter, each manufacturer using slightly different technology and hence have different programming algorithms, voltages and timings.
At the moment, there are a tiny number of the National Semiconductor DM74S571 available, which all the schematics for prom programmers I have found on the internet support; the most common one available for reasonable amounts seems to be the Czech made Tesla MH74S571 which is a very different beast. Looking for a data sheet that detailed programming information yielded only a page in Czech (attached); not a language I am overly familiar with, but was sufficient to confirm that a programmer for the NS DM74S571 would definitely not do the job.
My knowledge of Czech being as it is, it was not immediately apparent what the algorithm should be. However, by using an online OCR page [1] and Google Translate with some manual correction of the OCR and a lot of wild guesses, I have managed to translate the important details (attached too!)
While discussing this issue SiriusHardware pointed me to a page on Matthieu Benoit's website [2] which had code for a Hilo ALL03 programmer that was known to work for the Tesla chips; despite being commented in German (Which I can sort of make sense of) it seemed to conform to the translated datasheet in all details except the programming voltage is set to 21v rather than the 10.5v the data sheet says. Code in the program that is commented out appears to show that it was tried at 10.5v and changed to 21v. Its possible that the figure in the data sheet is a typo, because as I mentioned the code is known to work.
Anyway, I thought I'd deposit the results of my digging because it may be of interest to others; later in the year I'm going to try to design a programmer for these chips, and will publish the design once it works. Hopefully before supplies of these chips dry up!
[1]
https://www.onlineocr.net/
[2]
http://matthieu.benoit.free.fr/all03/source.htm#new_pcb