X250 strange problem

[Swonco]

Hi Guys,

Strange and interesting problem with my Thinkpad.

Subject: Thinkpad X240 with motherboard from X250 (original had 3-3-1 error). New RAM, new CMOS battery, BIOS updated to the latest version (1.42).

Problem: After motherboard reset (CMOS battery unplugged and plugged again) computer starts, boots, Windows load and everything works like a charm. Of course during first run errors 0251 and 0271 appear, but after updating the time and save/restart computer does not notify on any other errors. I can "soft" restart computer (either from BIOS or from Windows) and it starts again. But, if I cut out the power, using "shut down" or "hibernate" in Windows or unplug the main power, computer failed to start. Completely. No reaction on power button, any LED on keyboard light, no beeps. Mother board reset and it is alive again. Until next shut down. External battery and/or internal battery in or out - no differences.

And it starts to be interesting - I tried to check what will happen when CMOS battery is completely out. Computer boots as after mainboard reset. Power off = dead computer. But this time (only main power, without battery) it was enough to only unplug power supply to revive (quite obvious I guess). With external battery added - dead until battery removed.

So it seems for me that BIOS registers power off event and prevents to start computer again. Some security settings perhaps? Loading default settings from BIOS did not help (yes, I know that security and time setting are not changed). Any ideas?

And by the way - how to install this small plastic element that supposed to be mounted to the mainboard next to the external battery plug? I was able to remove it but not re-install.