I have a T43, model 2686-M7U, that is having the same symptoms that other threads have mentioned, works from battery, but won't charge when plugged in. It was most likely caused by my frayed power cord
I took a leap of faith and bypassed the fuse next to the DC input jack temporarily. Luckily, the laptop started charging the battery and none of the other components blew up
However, I need to replace the fuse, but it isn't marked like the other threads have suggested, it is in the same position though. The fuse is blueish in color, but I don't see any apparent markings. I can provide pictures if it will help.
Does anyone know the rating and manufacturer of the fuse so I can order another one?