[colug-432] SPARC "EEPROM" Battery Replacement

[Ethan Dicks]

On Fri, Apr 3, 2015 at 2:29 PM,  <jep200404 at columbus.rr.com> wrote:
> I had forgotten about those. Was it actaully battery backed up
> RAM? If I recall correctly, at least some had a conventional
> low power static RAM chip, maybe with some clock stuff, and a
> battery potted in epoxy to look like a tall 24 or 28 pin DIP chip.
> I might be confusing your EEPROM thing for what I messed with.

Old SPARCs absolutely used SRAM+clock circuit and an embedded Li
battery.  I'm not sure if they changed with the Ultra line or not.

> If one is desparate enough, one can use a Dremel to grind through
> the epoxy to the lead frame connections to the battery to
> disconnect the old battery and connect a new battery
> (with a socket!!!). I think there was some trick for loading
> data into it by plugging into a live socket in a running PC.

I've done that.  I have a couple examples of what works - there are
pictures on the Internet for the process.

Here's a deep-cut job - they took the backpack off and ran wires for
an external battery and left the clock crystal hanging over the SRAM
DIP...

http://www.kk.iij4u.or.jp/~taokamur/luna68k/img/NVRAM5.jpg

-ethan