[rescue] SUN 3/50 IDPROM chip replacement

[Jonathan Chapman]

Just a follow-up, I pulled mine out of my Sun 3/50 and it's an AM27S19A, which is the high-speed variant of an already fast chip. It's tristate output. One of our suppliers has some, which I've ordered.

Some of the arcade folks have cross reference parts like the MMI 6331, but they do not meet the speed requirements of the -A suffix part. The silkscreen under the IDPROM socket also has the -A suffix, so I was unwilling to blow a MMI 6331 to find out if it was fast enough (they're one-time programmable fuse PROMs, and are getting pretty expensive!).

The Data I/O 29B with UniPak 2B does in fact handle them, though! If anyone else needs some, contact me off-list and I cam program them for you.

Thanks,
Jonathan

On Friday, February 2nd, 2024 at 07:47, Jonathan Chapman <lists at glitchwrks.com> wrote:

> 
> 
> Jan,
> 
> Looks like some of the arcade supply places have blanks for around $10, I can program them on my Data I/O 29B, so if you want I can program one for you! I have a Sun 3/50 I can test in.
> 
> The outputs for that part # are open collector, which is going to be hard to find in a modern replacement (pretty much all modern EPROMs/EEPROMs are tristate outputs).
> 
> Thanks,
> Jonathan
> 
> On Friday, February 2nd, 2024 at 04:15, Jan Liška via rescue rescue at sunhelp.org wrote:
> 
> > Hello!
> > 
> > I’m restoring an old SUN 3/50M and its IDPROM chip is missing, which results in "ID PROM invalid error" when the machines tries to boot from net.
> > 
> > I found out that the PART # is 520-1295 and the chip is 32 bytes bipolar PROM, probably Signetics 63S080 PROM requiring a special programmer.
> > 
> > Is there any modern replacement or alternative available?
> > 
> > Thank you.
> > 
> > Jan
> > 
> > sources:
> > http://john.ccac.rwth-aachen.de:8000/misc/sun3_60.html
> > https://archives.retrobridge.org/sun/system-handbook/3.4/Systems/Sun3/CPU_03_IDPROM.html
> > 
> > _______________________________________________
> > rescue list - http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org