Strange power problem

[Lka1988]

I like this place....

I have a t42p with an interesting issue. I've researched a lot on it, and the only other issue that seems close to what I'm experiencing is the infamous loose GPU. However, what I'm experiencing doesn't exactly fall in line with a loose GPU.

The issue is that the laptop will lose power at seemingly random times; everything instantly shuts off, LCD, led indicators, fan, HDD; it doesn't matter whether I'm on battery or wall power, with or without the battery. This only happens when it is moved in a certain extremely-difficult-to-voluntarily-recreate way, usually when it's on my lap or if I'm doing homework while laying in bed... Though I did recreate it once by lifting the whole thing by the top of the lid while open and wiggling it in the air... it didnt like that too much >.<

Machine specs in my sig... It's an old corporate machine, and has been dropped in the past, as a small part of the case is broken off on the left-rear corner, but this issue just surfaced a few days ago (just as I was updating my wife's windows phone to WP 7.8... close shave). Otherwise it runs just fine. Also, I bought a new battery a few weeks ago, I'm not sure if that has anything to do with this, but more info is better anyway...

Any help is appreciated, I will continue to research it myself and stay updated here.

Thanks in advance,
Lane

[Neil]

Not sure that my experience has anything to do with your situation, but, lately my X40 would shut down just like you describe. I finally traced my issue to be to pins on the CF card adapter I'm using would touch the underside of the palm rest at times, shorting it to ground.

I guess you could have a similar issue, where something on the system board is able to contact something it shouldn't, cause a power circuit to short to ground. That will certainly shut things down in a hurry. Unfortunately, I have no idea where to direct you to look for such possibilities, but maybe someone else will. Or offer a completely different avenue altogether.

Oh! And, welcome to the forum...it is a pretty great place for us ThinkPad fans.

[Lka1988]

Thanks for the quick reply.

Yeah, this is a weird one. Definitely not a card issue, I don't use expansion cards. I mean, its so similar to the loose gpu issue that I'm tempted to tear into it just to look.

[RealBlackStuff]

During your searches I'm sure you must also have come across the 'loose Southbridge' syndrom.
Which is most likely what your laptop is suffering from.
Only remedies: have the chip reflowed (better reballed) and while you're at it, do the GPU also, OR a new motherboard.

[Lka1988]

I saw a little bit about that, I assumed it was the same as the gpu, but apparently not. I'll check that out, thanks

[Lka1988]

One question, first.

Once I dig into this, how do I tell if one of the chips is loose? Or are they literally just wiggling around in there?

[Neil]

No they are not usually loose enough to dectect any movement. The usual way to check is apply a little pressure on different areas of the chip(s) in question, then boot the machine while maintaining pressure, and see if the problem goes away (pretty difficult with an intermittant issue such as yours).

BTW, the GPU chip is about middle of the keyboard area, and the Southbridge chip is beneath the wifi card (under the touchpad). While you're in there looking around it still wouldn't hurt to look and see if any of the ground plats on the palm rest and/or bezels are bent out of shape to where they could contact a power trace.

[RealBlackStuff]

Those chips are BGA (Ball Grid Array), meaning they are connected to the motherboard with about 650 tiny solder balls.
If one or more loose their connection (through flexing or other mistreating), the laptop starts acting 'funny' or stops working altogether.
You can't see it, only experience the symptoms. These have been described extensively in many posts in the T4x forum.
Suggestion: start with reading the 'sticky' threads.

[Lka1988]

Those chips are BGA (Ball Grid Array), meaning they are connected to the motherboard with about 650 tiny solder balls.
If one or more loose their connection (through flexing or other mistreating), the laptop starts acting 'funny' or stops working altogether.
You can't see it, only experience the symptoms. These have been described extensively in many posts in the T4x forum.
Suggestion: start with reading the 'sticky' threads.

Thanks for the info. I've delved quite a bit into the stickies, I'm no newcomer to forums. I only asked because I had no luck finding anything like my issue. The only issue that came close was the loose gpu, but like I mentioned above, the symptoms weren't quite in line with what I am experiencing. Hence the new thread.

[systemBuilder]

The only time my laptop suddenly powers off (T42) is when I am running on a battery and the battery gauage is overly optimistic. In that case, the laptop thinks I have another 10 mins or something, but the voltage droops so fast that the whole laptop suddenly shuts off.

Maybe when you are moving the laptop, the power plug is coming lose, causing the machine to switch over to battery momentarily, and the bad battery causes the power-off.

I had a T41 where the yellow power plug (in the laptop) failed, and if there were no battery installed, it could easily die when moving the laptop around. There are lots of these jacks for sale on ebay, probably for a good reason.