DS12887 pcb substitute with battery

[Chuck Guzis]

On 01/22/2017 10:57 AM, allison wrote:
> I don't know about most people but this solution has been around for 
> decades.
> 
> I locate the battery on the failed part with a small magnet, then
> grind the epoxy down to it then pick it out with a sharp pointed
> tool.  Once I expose the connection point I older two wires then
> epoxy a small coin-cell holder in that spot and it s done.  I've done
> this more times than I care to count and its effective and the
> replacement battery some over 10 years old now have not failed.  But
> just in case I have a bag of NOS replacements (and pulls from
> socketed boards) all with dead batteries from age.  There is no magic
> to this.

It's worth noting that the original post was about fabricating a
replacement using the DS12885A RTC chip.  However, most old PCs used the
DS1285 RTC (inside of a DS1287  module).  The DS12885A is supposed to be
drop-in compatible with the DS1285, but apparently, in some cases is not.

So there's logic in reworking the old DS1287 modules, as the DS1285 chip
is long out of production--you'll most likely have to be content with
pulls or the occasional NOS lot.

--Chuck