IBM Thinkpad 560Z CMOS Battery Connector Polarity

Thinkpad 560Z Lithium Cell Polarity
Thinkpad 560Z Lithium Cell Polarity

Two years ago I converted a $20 Thinkpad 560Z (they’re more expensive now, oddly enough) into a digital picture frame for Mary’s parents, a process documented in two of my late, lamented DDJ columns there and there. It runs a stripped-down Slackware installation that boots directly into a picture viewer, so when you turn it on you get pictures and nothing else. Well, after you get a few screens of the usual white-on-black Linux boot messages, which I think adds a certain geeky charm to a digital picture frame.

Anyhow, the thing failed just before Thanksgiving with BIOS error messages 161 and 163: its way of telling you that the lithium cell powering the clock chip has gone dead. I hadn’t replaced that cell when I did the conversion and it lasted just about exactly a decade; it was evidently the right size for the job.

Not being constrained by the confines of the original laptop case, I replaced the coin cell with a grossly oversized CR123A cylindrical lithium cell (having a bunch of them on the shelf and some holders for another project). The connector is in an awkward location, below the IDE socket’s flex-PCB cable, and both wires popped out of the connector shell when I pulled on them. So it goes.

The top picture shows the proper polarity, as seen inside another 560Z’s lithium cell compartment: red-for-positive on the right, with the circuit board positioned component side down (toward the keyboard). Our daughter did the soldering; she’s since learned about heatshrink tubing and cold joints; it’s good enough.

This picture shows the CR123A all wired up and ready to go in the picture frame. The circuit board here is component side up, so the connector wires go the other way. Notice the small trace from the red-side pin on the circuit board; that’s your clue that it’s the positive battery connection. Measure the voltage at the backside of the connector to be sure you have those miniature pins properly seated in the connector, too.

CR123A in 560Z Picture Frame
CR123A in 560Z Picture Frame

FWIW, I bought three 560Zs while they were cheap; our young lady installed Puppy Linux on the one in the top picture (hence her soldering) and seems reasonably content. They’re old & slow & cramped by contemporary standards, but just fine for most of the things you’d probably buy a fancy new netbook for.


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