MacBook shuts down during Apple hardware test

[tripan]

Hello to all!

My Macbook (white, late 2007) started acting strange lately, apps like logic quit unexpectedly, first note of text I'm trying to type in spotlight don't appear, skype freezes the entire system while audio connection is still running, etc.

I ran the Techtool pro tests and everything passes, used all the Onyx maintenance scripts, reset PRAM NVRAM and SMC and finally I tried to run the apple hardware test from my original Leopard install disc (I'm running Snow Leopard now)

The short test runs full 1 time out 5 and ironically reports no problems but 4 times out 5 the macbook shuts itself off 2 minutes into the test while the progress bar is at about one-third and the display still says it's testing the memory. I have 4 gigs of genuine kingston ram installed and it passes all tests in techtool..

Also, I had issues with the mac shutting down 2 years ago during hot summer days, the fan was running crazy, so I opened it up, cleaned the fan and surrounding area from dust properly and re-installed the heat sink with appropriate sillicon paste which solved the problem, I never had a random shutdown ever since, although the fan runs quite fast, smc fan control almost always says it's around 6200 rpm and the temperature is usually between 60-80 Celsius.

Please someone give me suggestions what this shutdown-thing could mean!

Much appreciated! Cheers

 

[chscag]

Those temps are high and the fan is running way too fast. Probably a good idea to open it up again and check the fan and heat sink once more. You may also have a bad temperature sensor on the logic board which can cause the fan to run to high RPMs. I also suggest uninstalling SMCFan Control to see if that makes a difference.

The sudden shutdowns are probably being cause by overheating.

 

[tripan]

Okay I'll probably check it out..I only use smc fan control for monitoring the temperature and rpm, I didn't make any settings or adjustments though. I'm gonna uninstall it just in case!

Still, if this whole thing is caused only by overheating then why is that ultra processor-hungry tasks like running Logic never caused a shutdown anymore but a simple hardware test did after just 2 minutes and again, 3 times in a row? May that be the overheating already caused some damage to the logic board that neither techtool, nor apple hardware test (the one that actually went all the way) could spot?

 

[chscag]

Can't answer that except to say maybe the AHT taxes the CPU and GPU harder than Logic does. And you could be right about possible damage. The AHT is not all that great for spotting deeply rooted problems anyway, but TechTool will generally catch most hardware glitches.