27 Sep
2021
27 Sep
'21
8:28 a.m.
I can do them with the Data I/O 29B and UniPak 2B. Some of the other UniPaks can handle
them too. They are one of those devices that most of the newer commercial programmers
can't do. I wouldn't call the Data I/O really affordable, though.
If you want to send us a blank we can program it for you, or we probably have some blanks
for that part # on hand.
Watch out buying blanks on eBay, they're often pulls and are actually already
programmed. Also the yield was not 100% even back in the day, apparently, so buy several
to ensure you do get a good one.
Thanks,
Jonathan
??????? Original Message ???????
On Monday, September 27th, 2021 at 11:23, Tom Hunter via cctalk <cctalk at
classiccmp.org> 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)?
Thanks and best regards
Tom Hunter