ThinkPad T21 does not start on battery only. Is OK with char

[ANTIK]

My Thinkpad T21 will not start on battery only. Indicators turn green (ventilator and disc try to run) for only less than a second and nothing more. If a charger/adapter is connected the machine starts OK, and then I even can disconnect the charger and continue to work. I only see a slight decrease in backlight intensity.
This started after I connected to the computer a defective charger.
I'm afraid some FET switch 'died'.
Does anyone know the startup circuitry?
Does anyone have the keyboard circuit or at least the connector's pin designations?
Thanks, ANTIK

[rkawakami]

Welcome to thinkpads.com!

It does sound possible that one (or more) of the MOSFETs on the motherboard has died. As far as we know, there are no schematic diagrams publicly available for any Thinkpad. Assuming that you want/need to know the pinout designation for the keyboard connector in order to turn on the laptop without the keyboard attached, then you can use the simple port replicator (FRU 02K8668) to do that. Mount the laptop in the port replicator (without the keyboard) and you can then press the power button on the replicator to turn on the system. These port replicators are available on eBay, like this one:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0196508319

There may be cheaper sources on eBay or locally.