[rescue] Sun Ultra 2 series PROMs

Jonathan Katz jon at jonworld.com
Thu Jan 2 20:47:42 CST 2014


A while back I was whinging that I had an Ultra 2 with a dead PROM battery.
And I have the same problem with my E3000.

All the old docs for sun4m and sun4c hardware discuss soldering batteries
and patching their voltages into the various pins to keep systems alive.
I'm working to recreate that so I can get my E3000 going (and maybe the
Ultra 2, but I boogered up that chip.)

I then took a look. The ICs for the Ultra 2 and for the E3000 IO board are
the same. ST M48T59Y-PC1s. Although NOS of these chips exist, I doubt they
still have good battery cells on them. Thanks to Google, we can find the


It looks like the + of my battery (3x 1.5V AAAs for right now... should
give me 4.5vdc) will go to pin # 28, while the - will go to pin 14. This
are at the complete opposite ends of the chip, a little different than the
various tutorials for the sun4c and sun4m class hardware that are out there.

Am I reading the diagram correctly, or after I hook all this stuff up, will
I have some pretty blue smoke? We'll see :D

Jonathan Katz, Indianapolis, IN.

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