A20m Startup Problems

[gkamieneski]

I returned from vacation to find that my ThinkPad A20M refuses to start
up. It was sitting in a mini dock all that time with no power so the
main battery did get run down.


When you press the power button, several status lights come on but then
only the rightmost, power indicator light remains lit. The computer
never gets to the point of accessing the hard drive or a startup
diskette. Also, the screen never comes up and I never have a chance to
get into the BIOS setup.


There was a strong lightning storm while this notebook was sitting idle
in the mini dock and I was away, however it is powered through a surge
protector strip which had not even been turned on. I have tested the
hard drive in another unit and the hard drive is fine. I have also
tried a spare CMOS backup battery and still no luck (not sure of the
integrity of the spare battery).


I guess my next choice is the CPU or the motherboard. Any other
suggestions? Thanks.

[mehtabbukhari]

Hmmmm ThinkPad A* & T* series laptops are showing this problem.

This is a very well known problem.

When you switch on the laptop please check whether CPU heating or not. You follow the link below to locate CPU and heatsink removal instructions.

http://www-307.ibm.com/pc/support/site. ... IGR-4PER6R

If your CPU is not heating that means CPU VRM (Voltage regulator module is not functioning) and this could be one of reason why your battery drained-out completely. If that is the case then you will have to locate three MOSFET on the board which is on the other side of the board or at bottom of the system board. MOSFETs will have marking IRF7811A.

Replacing these three MOSFET should help. If not then you have a serios problem.

Hope this was helpful.