on a very sunny summer day, don't laugh ;) removing just the fan assembly, I heated the GPU for at least 2 minutes with sunlight and magnification glas:
(the photo was taken while under sunshade)
let it cool down, then I put back keyboard, RAM, and palmrest. on power on still 1 long, 2 short.
made a test to melt tin with magnification glas (x2). it doesn't!
I retried w/o success a few times and then left power on for a short while.
off/on again and I see the thinkpad logo. )))
pressed blue and checked bios: v2.24 from 2008 (with 1.08 FW).
put in usb-stick to program bios for undervolting, but on boot didn't recognize the usb-stick with F12.
(as there is no disk nor dvd-drive inside, it tried network boot.)
restarted, set boot-mode to diagnostic knowing that this would allow to detect usb-device.
saved and rebooted. a short peep and display message: no fan.
aha! I had forgotten to plug the fan connector back.
did it and restarted. fan is running. again 1 long, 2 short.
let it run for a while. tried reboot again a few times w/o success.
is there a chance, running again w/o fan, and then first let it cool down completely before restarting with fan connected? (which is what's recommended when baking the mobo in an oven) What can go wrong? there seems to be an overheating protection. so it wouldn't kill the CPU, right?