Anyone have any experience replacing a Dallas 1287 with a 12887?

From: Ethan Dicks <>
Date: Tue Dec 31 15:55:01 2002

While attempting to revive a Compaq 286/SLT laptop for use as a
front-end for my UP600a programmer, I have found that the battery
on the DS1287 has died (no suprise there). What sucks is that
even after I run the floppy-based setup utility, after a reboot
(not a power-off cycle), the machine forgets what I just set,
both the data and time, and the geometry of the A: drive. Seeing
as how it thinks there's a 5.25" floppy and it's really a 3.5"
high-density drive at the end of the cable, as you can imagine,
it won't reliably read disks.

So... I have ordered a replacement DS12887 since they no longer make/ship
the DS1287. Couple of interesting app notes here:

What I'm wondering is if anyone on the list has ever replaced a DS1287
with a DS12887. One of the sheets seems to suggest that I'll need
an updated BIOS ROM (clearly not available for a 286 laptop) to drive
the extra stuff associated with the enhanced century rollover.

Alternatively, has anyone here successfully performed surgery on a Dallas
module? I have disconnected the battery from a Mostek 48T02 from a SPARC
and soldered on an external Lithium cell, but the packaging makes it easy
to get access to the battery wires coming down from the top (I even put
the battery on a 9V battery snap so it's easier to replace) I haven't
heard of anyone doing this for the more sealed Dallas modules.

So... anybody else suffer though this?


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Received on Tue Dec 31 2002 - 15:55:01 GMT

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