My Toshiba l20 starts immediately i plug in the charger and nothing come on the screen also all the indicator lights( I mean the power, charging, HDD lights) will still be off. in this state i can still switch it on and off with the power bottom.

wait... im confused. do you turn it on with out it being plugged in? and once you plug it in then the screen and lights shut off?

now the battery has run out so without the adaptor it cant be turned on. immediately i plug in the power adapor the fan will start (without touchin any buttom) no light will come including the screen.

at this state i can eject the ccdrom(which means there is power in the cdrom) put the pc on and off with the power buttom.

it sounds like the internal power supply is going bad. it is getting power to the distributor but it isn't sending power correctly.

that would be my guess

i guess you are right jermaghs07.

I have been to some sites which say, the problem is due to a dead chip called "MOSF power switch". Now my problem is how to locate this chip/chips on the board and replace them with new ones. I have the neccessary equipment and skills to change any kind of chip.

I will be happy if someone help me to loacate this "MOSF power switch"

Thanks

in most cases it is too expensive to just replace 1 chip on the motherboard and is cheaper just to buy a new motherboard. but if you are doing it yourself it might not be that bad. i would suggest getting a hold of toshiba and see if they can give you a schematic of the laptop hardware. normally tech support can give you something to go on.

hope this helps

another thing is you need to make sure that it hasn't harmed any of the other hardware in the computer before you just replace that one chip.

Dear sir
I have proble that display related. pc moniter for ok,
RAM for ok,SMPS for ok. solve my problem .
anythin masage (abcd.....)som no displa

Dear sir
I have proble that display related. pc moniter for ok,
RAM for ok,SMPS for ok. solve my problem .
anythin masage (abcd.....)som no displa

First of all i can't understand you!!!
second of all if you have a question regarding your own problem then you need to start a new thread. and please list as many details as you can and type legibly.

Thank you