486 EISA system

[Chuck Guzis]

On 10/14/2006 at 8:22 PM Teo Zenios wrote:

>Anyway the 2 battery parts on the motherboard are: Dallas
>DS1225Y-200 and ST micro MK48T87B-24. Is there a link to the discussion
(or
>website) on how to rig a lithium coin battery to this particular part? I
>have a dremel, battery holder, and plenty of batteries so this should be
>easy enough. Can the ST Time keeper RAM) chip also be rigged in this way
>(is it the same part as the DS1287 mentioned above)?

The ST product is a drop-in replacement for the DS1287, and I suspect the
location of the battery and crystal is the same as the Dallas part.

Here are details on rigging an external battery for the 1287

http://www.mcamafia.de/mcapage0/dsrework.htm

As far as the DS1225, I don't know exactly where in the potting resin the
battery is located--and I can't seem to locate any online information that
would give a clue.  You could always dig around and see if the battery's in
the middle of the package, as it is in the 1287, but no guarantees.  About
10 years ago, RAMTRON published an app note that pretty much said that you
could replace the DS1225 with their FM1608 part--I don't recall any
specific gotchas.

Hope this helps,
Chuck