Totally off-topic but digital compacts are greatly under-rated macro photography tools - they mostly focus down to an inch or two, and have good depth of field. A DSLR is fine if you want to spend 20 minutes getting that "flower with only one stamen in focus" look, but for anything less arty and more informative, a compact is the best tool for the job.
This was the root cause of the powering off/faulty contact - corrosion (ebay leaked battery I guess).
That's very interesting, thanks for showing us that. The more usual explanation for the turning off problem is that these sprung contacts gradually wear away at the pads on the PCB that they mate with, and a solution is either to re-build the PCB pads with some solder, or to add a couple of connecting wires. A more sophisticated solution is to add a tantalum capacitor soldered across the two pads.
None of that would solve this problem though!