I would also like to mention here that the BIOS CMOS battery that is installed at the factory is unnecessarily complicated and proprietary in design. But it could also have been for space-saving reasons, who knows.
How did I come to this conclusion?
The original battery looks like this:
⧉ HPIt is clear that when this needs to be replaced—which can certainly happen with such old hardware—you have to buy this specific type of battery for far too much money.
And that’s despite the fact that it’s a completely normal, standard, very inexpensive CR2032 button cell* – only that a cable with a small plug has been soldered to it (and the solder tag has been spot welded to it, as it’s almost impossible to solder such button cells directly).
So, renovations are underway:
I cut off the cable with the plugs from the previously empty batteries and stripped the insulation, then soldered it to a standard CR2032 socket*, like this one:
I used sockets that I had previously salvaged from defective desktop motherboards, but they were exactly this flat design.
Then I stuck the finished socket onto the motherboard with double-sided adhesive tape, accessible from the maintenance cover, close to the original position of the battery (cable length).
In the future, I will be able to use “normal” CR2032 batteries, as with desktop motherboards.
Next, I will address the software side of this project.