On Apr 8, 2005 10:57 PM, Saquinn624 at
aol.com <Saquinn624 at aol.com> wrote:
I pulled the coin-cell holder off of an old PC clone
PC board and then
epoxied it to the top of the NVRAM- works well and will make future changes easy.
I thought about that, but I was worried about long-term mechanical
stability, and vertical clearance (with Sbus cards).
Ethan- the DS1287 is the one used in SGIs (I2, Indy),
isn't it? how did you
go about fixing it? [e.g. where in it is the batt. &cet.](all of my SGIs are
currently working, but the clock is ticking . . .)
I do not know what is used in the Indy, etc.; this one was out of a
Compaq SLT/286. I didn't have a replacement, and when I got a sample
of the modern part (DS12C887?), I noted several compatiblity warnings.
I opted instead, to recycle a DS1287 from another board that wasn't
quite dead yet. That's what's in the SLT at the moment.
As for the surgery, when I had nothing to lose, I started dismantling
the top of the DS chip... it seems that several of the pins that are
not present at the bottom are in fact bent 180 degrees to the ordinary
orientation, and are present at the top. I carved away the epoxy
until I could tear out the cores of the old batteries (this was
exploratory surgery after all). I eventually discovered where the
battery leads are (around pins 5-8, IIRC), and could probably just
detach the cells from the chip in the future, rather than have to do
deep excavation and extraction.
I now have a single DS1287 with much of the top half excised, and with
a 9V battery lead soldered in place with the same polarity as my 48T02
experiment. I think it might take 20-30 min to carefully repeat the
procedure with only enough hacking as to expose the leads enough to
sever them and attach a pair of wires.
At some point, I want to get some pictures, but there are plenty of
things further up the list (like setting up a nice shadow box and
continuous backdrop for said pictures...)
-ethan