This page is based on Peter Wendt's work. Original HERE.
You have either a PS/2 Model 25-286, 30-286, 55, or 65 which comes up with a "165 configuration error", and fails to retain the system configuration when power-cycled. Well, these machines have the dreaded Dallas DS1287 "all in one" Real Time Clock (RTC) chip with integrated Xtal and battery. Now the battery is dead, configuration is lost after relatively short time again and you get error-codes constantly. A really new, fresh and unused chip is hard to get. Even its successor DS12887 is pretty hard to get and darn expensive. At that point you wish you could simply add an external battery. But you can't. There are no provisions for one. Not yet anyway...
Ed: This same method is usable for other non-IBM systems that use one of the all-in-one Dallas RTC modules.
Have a look at the graphics below. Basically the DS1287 is a DS1285 chip, where the pins for the xtal-connection and the battery are bent upwards. Then the battery and xtal are placed atop of the chip, connected to the pins and everything is covered with a pretty rigid protective compound.
The DS1387 is the same chip with an additional integrated 4K SRAM. All described modifications apply to this chip as well.
What you need to do
NOTE: Don't be afraid: this chip is really hard to damage. If you have a multimeter test the voltage on pins 16 and 20 before and after. Before it may read anything from some 100mV up to 3V (where you should ask yourself *why* you wish to modify this chip ...?) and after it must be 0 (zero) latest after 5 seconds of measuring.
When you get a 0V-reading, you have successfully disconnected the battery.
Results & Feedback
Moritz Hoffmann from Germany shared his results:
Reworked chip inside a Mod. 65SX
Side view of modded chip. Note the battery holder!
Curiosity killed that cat. After the dust cleared...
Above pictures © 2006 by Moritz Hoffmann & his father.
Chris reported the following:
My old computer has been out of action for months, but this week I got
it going again by following the instructions on your webpage "Reworking
the DS1287 RTC chip".
Gary Jay in Ohio, USA reported the following:
Hi Peter...just thought I would let you know that
I got the DS1287 reworking on my first try!
Emmanuel Da Piedade from France wrote me:
D. Howe, USA did the modification for his Dell 4100 computer, he reports:
Above 2 pictures © 2009 by D. Howe.
From William R. Walsh (original here):
If you follow the procedure described here, you'll probably do fine. Unless of course you're like me and have more bad luck than you should when things come down to the wire. The suggested implement to open these modules is a Dremel tool. My Dremel tool--while a nice piece of equipment--spins at a minimum of 5,000 RPM and was all too happy to open not only the potting compound, but also the IC and in some cases, even the battery. I went through five or six DS1287 modules before deciding that this method wasn't going to work for me.
You will remember that I said something about a judicious application of violence on the Model 25 batteries page ... maybe I was getting a little carried away?
In any case, I turned to hand tools...I started with a sharp knife to make the initial cuts and followed them up with by running the jaws of a needle nose pliers into the cuts. The serrations in the jaws slowly dug deeper into the potting resin and it wasn't too long before I saw the first battery contact. For the second module I reworked, I did all of the work using a moderately sized side cutters. This was quicker, although it made more of a mess and the module didn't solder as nicely as the first. Whatever you do, handle the pins on the module carefully. They have a tendency to bend when you aren't looking. If you fix the bent pins too many times, they will break off. That usually ends the experiment before you've even arrived at the part where the module is exposed to the blistering heat of your soldering iron.
When you get past the potting compound and into the terminals, clear away just enough potting resin to catch the negative battery terminal heading up to the top of the package. When you've exposed this, punch through it with a nail, awl or similarly sharp device. You want to be sure the battery is disconnected, so double-check with a voltmeter. It won't do you any good to "charge" the depleted button cell. It could start a fire, explode or just make a smelly mess.
Soldering was the next big thing. I didn't feel up to soldering a CR2032 holder onto the module (and there's the question of finding one in stores around here), so I purchased a triple-A battery holder and some batteries from Radio Shack. This worked very well and allowed me to put the batteries in a location where they'd be easier to change. In the event of a battery failure, the holder can be placed away from the sensitive planar or other circuitry.
To give the newly reworked module some more strength, I used hot glue to secure the battery leads and holder inside the system unit.
The above picture shows a reworked module installed in a PS/2 Model 55SX. I couldn't get far enough away from the planar with my batteries, but I'll keep an eye on them periodically.
This picture shows the second module I reworked in a Model 30-286. While this one didn't solder as nicely (and had to be resoldered once when the positive lead came unglued!) the battery holder is safely away from the planar and other parts.
If you do something like this, try to situate the batteries far away from the system board/planar or other parts inside the computer. Also be sure to use high quality name brand batteries, such as Energizer, Ray-O-Vac or Duracell. Be sure not to use rechargeable batteries.
Next up--when the depletion of the internal battery happens--will be rework tips for the "other" Dallas modules, such as the DS1387 Real Time RAMified module, as well as the 1287 variant that is used in my EISA Compaq DeskPro computers. There exists no modern day replacement for these, so re-energizing them is the only option.