Batteries for PS/2

Cheap Battery Alternatives

The Situation: You have either a PS/2 50, 60, 70, P73 or 80 (or an XT-286) and the battery is dead, configuration is lost after relatively short time again and you get the error-codes 161, 162/163. Or the internal clock will not display the correct date and time after the system was powered off for some time. (Hence: this is not neccessarily a battery problem.)
The Action: You try to get a PS/2 battery P/N 72X8498 for your system. And pay about 40$ (or 60 DM in Germany) for this.

"Isn't there any cheaper solution ?"

Yes - it is. Go to your local photoshop. Have your old battery with you and look for something labeled 'CR-P2', or 'BR-P2' (different manufacturer, different numbers sometimes), either from Panasonic, Varta, Sony or DL223A from Duracell ... or any other. All are 6V-Lithium batteries. Compare the two. Appears to be the same. Compare the price.
Wow ! Only a few dollars (or: only 26 DM here).
Take one of these batteries and leave the old one in the shop for recycling.
Problem solved.

Same situation as above but on a PS/2E, on Models 25SX, 56, 57, 76, 77, 85, 90 or 95. These models use a round button-type Lithium cell P/N 33F8354 - which is in fact a CR-2032. Easy to guess that these things are much cheaper in a department-store than supplied as a spare-part from IBM.
Same tip as above: remove it from your computer, go to a department store (photoshop / watches department), buy one with the same number or a compatible and leave the old one in the shop for recycling.

Same situation but on a Model 30, Mod. 25 (with 8086-cpu) or even some old ATs.
The model 30-0xx has a 3V-battery on the riser-card (slot card) and it is soldered, while the AT comes with a 6V-battery with a cable. If you are a bit experienced with a soldering iron and a multimeter, you will sure find + and - of the battery, unsolder it and install one of the cheap battery holders for 2 resp. 4 pieces of AA (Mignon) batteries. These holders come with a red wire for + and a black wire for -, are made of plastic and you could use some velcro-tape to put them i.e. at the rear of the unit or somewhere else. Make sure, that the terminals on the battery holder are insulated with tape and cannot contact metal surfaces or internal parts.
Use 2 resp. 4 high quality 1.5 V -AA-style batteries (i.e. Duracell, Philips or Ucar) and this construction will do until the year 2001 - or even longer. Don't use too cheap batteries. The relatively high internal temperature of a PC might lead to defective cells, these run out, cause a big mess and probably damage the systemboard.
You can use batteries, because -unlike to some Taiwan-boards- the CMOS/Setup-battery is a real 'battery', no accumulator. It will neither be charged during power on nor will be any kind of 'refresh-current' be applied on it.
That makes everything very easy.

Same situation on Model 25-286, 30-286, 35, 40, 55SX, 65SX. These units use so-called 'clock-modules' - which is an IC-style circuit (black box from Dallas Semiconductor) with a lithium battery molded inside. These can only be replaced as a complete part.
All the above mentioned machines use a clock-module P/N 8509237.
The DS1287 chip can be substituted by its successor DS12887 - which is pin- and function-compatible.
And there is a way to Rework the DS1287 with an external battery when the internal cell died ... not for the faint at heart and it requires some tools, solder capabilities and some more parts.

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