Dallas RTC 14287 with built-in Lithium battery...

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I have one Pentium Pro motherboard, which uses a Dallas RTC 14187
realtime clock chip (24-pin DIP package), with its own built-in
lithium battery.

When recently the battery inside the chip went dead, my system refused
to boot because the Bios enters a loop saying "system battery is dead,
replace" and restarts the boot process, going back to the ram test.

Now... thinking a bit about this... it SUCKS because:

a) Nobody can't warranty that Dallas Semiconductor will be around
b) what if they some day they drop the DS14287 ???.

My question: Is there a way to isolate the battery from the RTC chip,
so I can place an external watch-type battery without having to
purchase a new RTC chip from Dallas every time the battery dies?.

as I said, the chip is a DS14287.


Re: Dallas RTC 14287 with built-in Lithium battery...

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The DS14287 comes in several packages. Each package is pin for pin
compatible and I think the EDIP is the same size as the DIP. Replace the
EDIP with a standard DIP component. Add a 32.768khz crystal to the X1 X2
pins (marked NC on the EDIP) and add a batery holder (glue it down some how)
and connect it to the correct pin (again this one is NC on the EDIP). I'd
check to make sure the pins on the MB are really not connected. If not you
can bend those pins up a bit and solder to that. (I wouldn't be surprised if
they actually put a place for a battery holder and crystal, but it was
cheaper to use the all in one.)

Another thing to try is to see is if you can connect a battery to the
NC(VBAT) on the EDIP and see if that does anything.

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