T40 LED Status Indicators Not Working

[EmadYousuf]

Hello Everyone,

The status indicators on my laptop are no longer working, these include the power/battery/numlock/capslock led's. Basically the entire row of lights on the front of the LCD.

Some background info: Just finished replacing the LCD (cracked) with another used T40 LCD, bought from eBay. The replacement unit is a complete top portion, so I had to remove the laptop trim to replace the LCD unit.

So far I have already tried switching the inverter from my old LCD into the new LCD unit. (since the status lights are part of the inverter). I have also tried using my original LCD cable, again to no avail.

The thinklight is working fine on the new LCD unit, so I don't think the problem's with the LCD cable. I also don't think the problem is with the inverter, since I've already tried switching the original inverter (from the cracked LCD) into the current LCD panel.

All this leads me to believe the problem might be on the motherboard. Hopefully someone knows the solution

Emad Yousuf

[richk]

I have seen similar cases where I concluded that it was the motherboard with no other symptoms. It also might be dirty contacts on the motherboard connector, so I would clean them with electronics cleaner or denatured alcohol.

[xyz]

I have the same problem, but in my case I have replaced the motherboard, but i have tested the lcd cable on another machine and for sure the problem is on the motherboard.

Will try cleaning the board.

Another member here reported he had a similiar problem and in his case he had bent some of the pins on the mb and he corrected this and all was fine..

cud also be a blown resis or something, anyone know more about the circuit ?

[EmadYousuf]

Do you have this problem on your current m/b or a previous m/b which you replaced? I can't imagine where on the m/b the problem could be, I have tried cleaning the motherboard already, again no go.

How can I search for this thread regarding bent pins, which you mentioned? keyword/link?

Thanks;

[xyz]

This is on the replacement board i have,

Just examine the board under a magnifier and look where the clip attaches for any bending of the pins.

otherwise it will be a blown resistor or something on the board.