T500 instant-off If I tap the Case

[spacedancer]

Hi all.
This is a first post re anything other than Mac.
I was given a T500 by my sister-in-law. She told me it worked but couldn't remember exactly what "issues" it did have that caused her to put it away when she went Mac.

I figured it would be useful to have a Windows laptop, so I started working with it.
It does have "issues" and I'm trying to determine what to do.
It shuts off if I move it in a certain way, sometimes giving me the 1-3-3-1 beep sequence.

Removing & resetting the 1 Gb memory chip clears the beeps & it starts normally, but will shut-off (the battery & AC lights say lit) when it's moved again.
Also, if left to sleep longer than 20 min or so, it won't won't wake.
The light to the left of the AC & Battery (one that looks to me like an "N" in a circle tilted sideways) stays lit, but a hard shutdown is the only option from that state.

Yesterday, after removing re-installing they keyboard (as far as I dared go) I discovered that if I tap the case in the upper right corner directly above the DVD drive, this causes the "instant shutdown"... (the screen goes dark instantly with only the battery & AC lights staying lit).
So moving or slightly jarring "something" near that area seems to be where the "issue" is, at least that's my guess. Other than that knowledge I have no clue.

As long as the thing is running & not allowed to sleep, and not "tapped" as above (or torqued in any way really), it runs normally.
Actually to my surprise I've sort of started to like the T500.

When I got the laptop, on the cover was a post-it from a repair tech that used to fix her "stuff". It said
"I removed & cleaned a few things & everything seems to be working now."
...which leads me to believe this "instant shutdown" was the behavior he couldn't repeat consistently and was also the reason my sis put the thing away.

Does this problem sound familiar to anyone? online the 1-3-3-1 says bad motherboard.. I think I also read replace DIMM, but if I tap right where the DIMM is nothing bad happens, only the upper right corner reproduces the problem.

I looked on ebay and found a barebones used motherboard with CPU (all drives & cards etc pulled), verified/guaranteed working for $30 plus shipping. Since everything on the T500 seems to work perfectly well other than this "power-off if you move it thing", I figure I can swap everything and install all on a good motherboard.

If it is the motherboard, can I do a remove/replace without too much difficulty myself?
Would someone on the board be able to give me a set of basic instructions?
Thanks,
SD

[Brad]

Welcome to the forum!

Download the Hardware Maintenace Manual here.

This document includes all the steps needed for complete disassembly of your T500.

Brad