T41 Turns on when AC Unplugged

[NerdPope]

My friend's T41 (type:2379) has a very unusual symptom. When you unplug the AC adapter, it turns on (even if system is closed. Of course this occurs with the battery in, even tried swapping batteries with both of mine and different adapters. Shutting down on battery will not turn off the system, it just starts back up. It looks like it shuts down, then turns back on.

Also, it will not turn on from the battery alone. If the system is devoid of adapter, and battery, and the battery is reinserted, it will not turn on. I have tried the 'old trick' with the disconnection of all power and depressing the power button, but no changes.

BIOS is up to date, no previous problems, and I have it fully disassembled, no liquid, or physical damage present.

So to recap;

1.) Disconnection of AC adapter turns system on.
2.) Will not shut off on battery (shutdown or hibernate).
3.) If off, will not tun on on battery.

Ideas?

UPDATE: System will not wake-up by disconnecting the AC adapter while in sleep mode.

2nd Update, this is almost like micl9's problem: differences in red.

When on battery power:
If I shut down via XP - it restarts after shutdown.
If I force a power-down (hold pwr key) - it stays off but will not power back up (pwr key does nothing) until either;

a) I pull the battery and when I reinsert the battery it WILL NOT starts by itself or with power key.
b) I plug into AC pwr - it does not start up by itself, OR when the pwr key is pushed.

[Battery and AC must be disconnected for about a min for the system to be usable again, will only turn on with AC]

When on AC power:
If I shut down via XP - it stays shutdown. And power key functions normally to turn back on.
If I force a power-down (hold pwr key) - it stays off. Battery indicator blinking green. And power key functions normally to turn back on.
If unit is off and I pull the ac power it starts up by itself.
Essentially when on AC power it behaves normally.

[netzspannung]

Check backup battery maybe - just a guess.

Also, there is some capacitor tied to the power button - I noticed that even an OK machine will not resume from standby with a single push. You have to actually hold the button like 0.5 sec... don't know what that is, exactly, but it might be related to your problem

[micl9]

I had a similar issue with a T21
Thread LINK

Turned out to be a bad power key - so try another keyboard if possible.

Good Luck!

[NerdPope]

Thanks for the input netzspannung.

Backup battery checked, swapped, to no avail. This capacitor makes sense, but I've held down the button till my hand goes numb with no results.

Additionally I have re-flashed the BIOS with no improvements.

First 48 hours as a member of these forums and I must say that ThinkPad enthusiasts are the best people I've ever met. Especially for all the effort and help that went towards that student.

[NerdPope]

I had a similar issue with a T21
Thread LINK

Turned out to be a bad power key - so try another keyboard if possible.

Good Luck!

I swear, if that's all it is I'm going to laugh my butt off!!! Will give it a try soon.

EDIT: Just did keyboard swap, not laughing here. still open for suggestions. I even tried shutting down again without the keyboard, still started back up again.

[RealBlackStuff]

Try it without a hard disk in it, maybe it's a freakin' Windows setting while sleeping...

[NerdPope]

Symptoms still the same, I have even tried my T41 hard disk.

Even tried it with the CD-ROM, MODEM, WiFi removed. And disconnected the keyboard while windows was shutting down. No improvement. the darn thing booted right back up.

[RealBlackStuff]

Try booting while making a boot-log.
Upon start, press F8 a couple of times till you see the menu.

Also, go into Start/Control Panel, doubleclick System, select tab Advanced, click on Startup and Recovery Settings, and UNtick Automatically restart.
You may have an error that you don't see.
And also check the system error events log.

[NerdPope]

Boot log turns up no driver or any other errors. Disabling restart on error does nothing.

To be more specific, the system (hardware) shuts off when you 'shutdown' windows. But if I'm on battery only, it will literally turn back on. I'm not talking about windows restarting, or windows restarts instead of shuts off. The darn thing just powers back up on battery power.

Swapping hard drives, isolates a software issue. This issue lies within the motherboard. It is quite possible that my friend's ThinkPad has a permanent illness without a transplant.

I am hoping someone else has come across a problem like this and was able to solve it without replacing the system board. Could it be a fuse, a known poor solder joint, a missing jumper, anything.

[Harryc]

Check the power management settings in BIOS...particularly any that start with 'Wake on'.

[micl9]

I think a few posts back you tested w/o a keyboard. Did you try with a different keyboard?
If the keyboard is faulty and that fault is physically an open circuit, testing w/o a keybaord would also represent an open circuit and result in the same behavior.
My T21 did exactly the same shut down - poweroff - poweron.

Just for grins try another keyboard. If you don't have one ask around on the forum for a damaged keyboard (ie broken or missing keys) all you need is a functional power switch.

EDIT - Ok so I am at work and did not read the post very thoroughly - looks like you did swap keyboards in addition to no keyboard.

Are you sure the swap keyboard worked?

[RealBlackStuff]

Have you tried another main battery?

[NerdPope]

I have narrowed it down to the board. I have swapped everything with my T41, including the LCD. I've ran it bare bones without Wifi, modem, touchpad, CD-Rom, and speakers all while swapping hard drives, CPU, LCD, Batteries (I have 3 on hand), BIOS Battery, keyboards, Ram sticks, and AC adapters.

Will not stay off on battery with a Linux CD either.

Drivers have been checked, BIOS has been re-flashed to latest twice, BIOS has been set to defaults dozens of times, devices in BIOS Have been disabled, and I have applied pressure to the ATi chip even though its never been a problem. Battery contacts are cleam and continuity test from the terminals to board were verified with a Fluke multimeter.

The sucker just doesn't like to power down on a battery.

We should charge my friend for a very thorough diagnostic.

So, I take it no one has ever seen this before?