Lenovo T400 wont turn on

[wisdomkeeper]

Hardware - Lenovo T400 C2D P8400, 3GB RAM...Intel 4500MHD
Problem - The laptop will not turn on. After I connect power supply, powers up on it's own - Z lights up, battery as well. After 1-2 seconds shuts off on it's own. If I press the power button, the Z lights up, as well as CapsLock/NumLock indicators(and then capslock/num lock indicators turn off, but Z stays ON). Fan spinning, hdd spinning, DVD drive clicks a few times and then stops - that's all. Tried to remove the main and backup battery - no change, no POST, no image on LCD. Tried to remove memory - no beep, nothing.
My mother told me that yesterday the laptop worked just fine. She watched some movies and turned it off. On the next day the laptop will not turn on at all. This is almost paranormal. Usually mobo - chipset/bridge defects start as some sort of a annoyance - artifacts , difficulty in turning on but it's the first time I have ever seen laptop to completely die with not reason. Seems like that only the charging circuitry and fan is working.

[TPFanatic]

After plugging it in and it automatically turns on, then turns itself off - wait and see if it turns itself back on again and repeats this itself a few times. Maybe CMOS battery died.

[wisdomkeeper]

After plugging it in and it automatically turns on, then turns itself off - wait and see if it turns itself back on again and repeats this itself a few times. Maybe CMOS battery died.

Sometimes it does. The problem is that It should be POST-ing/booting without CMOS battery and should just throw some kind of error during post (TIME AND DATE INVALID PRESS F2/ CMOS CHECKSUM BAD)
Well - CMOS battery - 3.08V When I plug the power supply, turns on by itself. After a few seconds turns off, and then on again. After a second/third time this stops, the battery and Z LED are ON, the fan is spinning, nothing more. No beeps, no POST.

[rjwilmsi]

A couple of items I've heard about/experienced:
* unplug power supply, remove battery. Press and hold power button for 30 seconds then release. Then reconnect and start as normal. Apparently a fix for excess static electricity build up.
* check no pins of USB ports are touching outside of ports. Touching pins causes e.g. X220 to power up but not go on to start POST.
* reseat RAM. Happened to me recently after opening a machine to check parts, machine would power on but not start POST, no beeps. Reseated RAM and all fine again.

[wisdomkeeper]

A couple of items I've heard about/experienced:
* unplug power supply, remove battery. Press and hold power button for 30 seconds then release. Then reconnect and start as normal. Apparently a fix for excess static electricity build up.
* check no pins of USB ports are touching outside of ports. Touching pins causes e.g. X220 to power up but not go on to start POST.
* reseat RAM. Happened to me recently after opening a machine to check parts, machine would power on but not start POST, no beeps. Reseated RAM and all fine again.

None of this is the cause of my problem. Tried all of this. Is there a option that the BIOS is corrupted?

[rjwilmsi]

None of this is the cause of my problem. Tried all of this. Is there a option that the BIOS is corrupted?

OK, sorry to hear none of those sorted it. I am not aware of, have no experience of, BIOS corruption issues, other than hearing of others having occasional problems after a BIOS upgrade (not relevant in your case).

[wisdomkeeper]

OK, sorry to hear none of those sorted it. I am not aware of, have no experience of, BIOS corruption issues, other than hearing of others having occasional problems after a BIOS upgrade (not relevant in your case).

I am still considering the option of trying to reprogram the BIOS EEPROM. I just don't know what else could be the reason for the sudden death of this thinkpad.

[rkawakami]

About the only other thing you can re-seat, which as far as I can tell has not been mentioned yet, is the CPU. Make sure you are statically discharged when doing so. There's a screw cam lock which holds the CPU in the socket. From looking at the Hardware Maintenance Manual, rotate the screw counterclockwise to release the CPU, lift it out slightly, replace it in the socket, press down on the top of the CPU and then re-lock the screw. Apply fresh thermal paste and re-assemble.

Actually, now that I think of it, you might want to try something simpler first... remove the keyboard and then connect the power supply. If the system still powers up on its own, then the problem is probably NOT in the keyboard. If the system remains off, then you've probably found your problem.

You might also gently ask your mother if anything out of the ordinary happened physically with the system (dropped, spilled something on it, wrong AC adapter plugged into it, was there a strange smell?, got too hot, etc.). Problems can happen at any time. Sometimes it can be caused by a physical event; a bump or drop can break a connection on the motherboard. Other times it's just a part's time to stop working.