T61 LCD backlight and activity lights won't turn on

[rarirurero]

My ThinkPad T61's hinges were loose so I opened it up, installed some replacement hinges, and discovered that it would no longer sense when the lid was closed. I was looking for the sensor that detects this and found it on the circuit board that has all of the activity indicator lights (the lights that flash when the HDD/WiFi/battery/etc. are active). This is attached to a ribbon cable that is also attached to the LCD and ThinkLight.

I had a spare of this cable, so I unplugged the one attached to the motherboard and LCD, and plugged in my spare (which was not attached to the LCD) while the machine was on. The activity indicator lights on the spare turned on and everything looked OK. Then, I shut down the machine, and booted it up with the spare cable (again, not attached to the LCD). None of the activity indicator lights turned on and later when I plugged the original cable back in, the LCD backlight and activity indicator lights (except the WiFi one) wouldn't turn on.

I'm guessing I overloaded something when I turned on the computer with the spare ribbon cable plugged in without the LCD as a load. Any ideas for fixing this, where a fuse might be, or what parts are screwed up? Otherwise I'm just hoping the VGA out works and I can at least use it as a desktop computer...

[RealBlackStuff]

...and plugged in my spare (which was not attached to the LCD) while the machine was on.

You blew it, literally!
Just don't know which fuse, or where, never seen a fuse-list for a T61.
Who in their right mind starts to replace parts on a running machine?

[richk]

There are 2 fuses on the top of the board near the lcd connector. They are small, surface mounted fuses and are hard to change without good equipment. (not a job for a radio shack soldering iron) You need a preheater and a good rework station. The T61 uses lead-free solder that melts at a very high temperature. What is the FRU of your board? If you don't know, post the full model number (like 7662-XXX) If it ends in CTO (configured-to-order) send me the model and serial number in a PM and I can look it up. Don't post the serial number in the open forum

[rarirurero]

Thanks for your response. I believe the FRU is 41W1487/42W7866 (are they interchangeable?).

[hwangong]

Did you fix the problem? Cuz I have exact same one. Plus my lcd doesnt work everytime I close the lid and open back up.

I have to "unplug" the inverter just about halfway from the vga cable to get the lcd work properly. But lights still doesnt work except wifi.