t30 will not boot

[thomaslp]

I have an old T30 that is not booting. It powers on the fan starts. If there are no memory in the slots then I get error beep codes. I insert a memory module and there are no beep codes and I get a little bit further. Now with the memory seated the laptop powers on and the backlight is turned on. But as soon as the backlight is turned on the laptop totally dies. I have to unplug the power for 20 seconds before I can turn it on again but again it dies as soon as the backlight is powered on. I tried the LCD on another T30 and it works fine. I tried to swap the processor but no result. I tried moving the motherboard into another T30 but here the result is the same....so I am pretty sure that it is some defect component on the motherboard. Any ideas? I have checked the coils that are often the problem on the T23 and T30 models, but they are all firmly soldered. Could it be the BIOS chip?

[SMA]

Can be failing memory socket(s).