Question:
Hi all, my Toshiba Qosmio F20 shuts down while plugged into AC power. I don’t know if it is an overheating problem, battery problem , AC jack problem, AC adaptor power problem or combination of these? The AC power LED switch is on and doesn’t flicker when I play with the jack. It won’t boot with the battery removed. The battery LED is usually orange but will turn green sometimes. Shouldn’t it power up with AC power alone? The battery isn’t charging well also. Could be battery needs changing? Don’t know. Please Help. I have took the machine apart cleaned it, applied new thermal paste (Arctic Silver) to both the CPU and GPU. I am at a loss for what the problem could be.

try to replace AC-adaptor. qosmio laptops are true toshiba laptops so, it must "tell" error code via light diodes.