But today I said 'No, today is the day I at least diagnose the problem', so I set about disassembling it, and the usual many screws later and it was all apart.
I started probing around and decided that I should start by buzzing out from the power socket, to see how far the 19.5v was getting into the board.
As it happens, it turned out to not be very far at all. Literally next to the socket is an inductor, and checking continuity from one side to the other, and nothing. So I started to look under the magnifying glass, and it looked like one side of the inductor had a cracked joint, so I got the microscope out to see if it really did. Boy did it:
- PXL_20231024_124723451.jpg (561.2 KiB) Viewed 258 times
So, a spot of flux, a cleanup and some fresh solder, and continuity was restored. It just goes to show how useful continuity tests are, and visual inspections.
All now running off the AC adapter:
- PXL_20231024_132859685.jpg (264.84 KiB) Viewed 258 times
Slightly annoying in that I could have probably fixed it years ago, but thought it was probably something much more complicated than a simple solder joint.
But there you go, a mechanical failure almost certainly as a result of a drop in that corner causing the board to flex and cracking that solder joint.