Real Challenge for X61t Gurus (X61t Powers Up and Shuts Down, but (!) Works with External Monitor
I've got an X61 tablet. It powers on, but shuts down in a few seconds. No video. Nevertheless (!) it works just fine with an external monitor... I checked the tablet's LCD with a working X60 motherboard - works fine. So I blamed the native motherboard. I purchased a replacement (same X61 with a bed hinge, turned on, worked fine). I removed the LCD with broken hinge and connected my LCD monitor to the working motherboard. Guess what happened? The new working motherboard shut down and now works only with external monitor and shuts down even when it's own tablet LCD is connected.
I found a "Display" setting in bios. It has 3 options: 1 boot with own display, 2 boot with external display, 3 boot with both. I picked the 3rd. When external display is connected computer does not shut down and video is displayed only on external monitor.
I connected my X61 LCD, the one that's just spoiled a working X61 motherboard to a password locked X60 tablet motherboard. It shut down in a few seconds. I connected X60 tablet LCD to it, it worked. This time the MB did not get spoiled. Clearly, something with X61 LCD or LCD cable.
If anybody had a similar experience or has any idea how to resurrect X61 mb I'd really appreciate any help.

it seems like an lcd inverter problem to me. Has happened to me a number of times, but not with my X61T.