I am preparing two IBM Thinkpads to give to less fortunate families at the moment, reloading the OS, putting in new batteries, buying power supplies, etc.
Each had 256MB RAM, which is not really enough to run XP very well.
When I looked at the memory chips in the machines, all ready to buy more RAM on ebay, I was surprised to find that they both had 512MB already installed (two 256 DIMMs).
The BIOS reported 256MB, and by swapping memory out and testing, I determined that the second memory socket was not working in either laptop.
It turns out, IBM had a slight problem with the solder connections breaking on the motherboard where the second memory slot connector is attached on the T30. (a major recall for IBM).
So the issue on both machines was that the solder connections between the second RAM socket and the motherboard were cracked. The cracks are very difficult to see, unless you have a stereo microscope handy.
Under very bright light with a 10x lupe you can see some very slight roughness or crustiness on some of the joints where there should be shiny solder, but it’s not obvious.
The unusual (and good) design is that you can do the solder re-work on these sockets without taking the laptop apart at all, other than removing the memory slot cover.
So, a couple dabs of rosin flux from the flux-pen, some careful close-up re-work with my Weller ESD-safe soldering iron, and ten minutes later bingo, two laptops with 512MB.
There are about 100 pins on each side of the connector, yet more solder was not needed, just a touch with the soldering iron to re-flow the solder.
While the completely correct SMD re-work method would be to pre-heat the board and use a hot-air pencil and some solder paste, this seemed to re-flow reasonably well as-is.
Few IT hardware repairs are this simple, fast, and easy.