5750 Shuts Off After 3 Seconds

bigreid

Very brief into of my self:

 

Have degree in computer science, and have been repairing computers since 1986.

 

Long and short:

 

Have an Acer Aspire 5750, i5-2450m, 8 gig system mem.

 

Picked it up brand new some time ago, and has never given me any problems.

 

Until just recent.

 

Upon starting the 5750 now, it comes on, Power Indicator light lights, and the fan starts and runs normal, not at 100%, and then unit shuts off after 3 seconds. No POST, (it doesnt stay on long enough for POST to kick in), and no Audible Error Codes.

 

Started working backward, using deductive logic, and researching on Google for all available input.

 

The 5750 does the same thing if I try to start it using the battery, or, without battery, using AC.

 

Then reset the CMOS. Made no difference.

 

Changed memory with known working memory. No good.

 

Plugged in external display, thinking GPU went. Nothing.

 

Thinking this is also a sign of overheating. Replaced the Thermal paste. No good.

 

While I was at Motherboard level, I decided to test to see if the CPU was even getting hot for those three seconds. Removed the heat sink, booted, CPU did get hot, (as it should), then 5750 powered down again in three seconds.

 

So I took an over sized heat sink meant for a desktop CPU, pasted it up, and affixed it to the 5750's CPU to see if this was in fact an overheating problem.

 

Same thing, shut down in three seconds. Not an overheating problem.

 

Kicks and giggles, I completely removed the CPU from the motherboard, and booted.

 

Same thing, Power Light comes on, Fan powers up nicely, shuts off in three seconds.

 

So I am down to either it is the CPU, or the Motherboard.

 

Correct me if I am wrong though, but would the CPU heat up if it were bad? Ive had bad CPU's that just stayed cold.

 

Heres the thing, I have no other Socket G2 boards to test the CPU, so my hands are tied.

 

Please, any help here, I dont have much hair left to pull out.

 

Thanks.

JackE

Nice write-up! And from your description and all you've tried, I'm gonna take a wild guess and suggest that you have a short in there somewhere. Perhaps a grounded screw is touching a trace or conductor it shouldn't be touching. Another possibility, especially if you have a habit of opening and closing the lid too much like I used to do,  is the display/camera ribbon cable or it's trace insulation failed. I can think of other possibilities too numerous to mention --- I'm sure you can too! A task that sounds like trying to find a needle in a haystack. But you also sound like the kind of person who's up for the task! 8^)

 

Jack E/NJ