On Nov 18, 5:47*am, "Tim Downie" wrote:
I've got a friend's ASUS M5200 laptop that I've offered to look at.

It works fine when connected to it's power supply but dies instantly if the
power is removed.

It can be as simple as an open fuse (but it'll be a surface-mount
soldered
in fuse). It sounds like the charging circuitry isn't doing its job.
Look for
surfacemount MOSFETs that have failed if the fuse isn't the problem
(or if the fuse, when replaced, blows again).

Basically, look at the power handling discrete components (fuse, sense
resistor, PMOS switch transistors, etc.) near the battery connector.