486 EISA system

[Teo Zenios]

----- Original Message ----- 
From: "Chuck Guzis" <cclist at sydex.com>
To: <cctalk at classiccmp.org>
Sent: Saturday, October 14, 2006 9:36 PM
Subject: Re: 486 EISA system


> 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
>
The ST chip is 2 layers that connect at the ends (seems to be some potting
there), I wonder if the battery is on the top player or the bottom. I hope
there is enough residual voltage for a meter to read so I know which half I
need to disconnect.

Nothing on the 1225Y then other then finding a replacement?