starts for 2-5 seconds and then powers down

[jcrowland]

recently, i had a pc die on me (it just wouldn't boot), so i decided i'd recycle the drives, peripherals, and case and it was time for a new motherboard, power supply, memory, and cpu.

i did some research, purchased an AMD Athlon XP 2400+ (AW7X-2.4+ 255 2.0Ghz), a Gigabyte GA-7VAXP motherboard, a 300 watt ATX powersupply, and a new 512M DDR DIMM. i put it all together, took precautions against static electric discharge, worshipped the cpu, and very gently applied with the heatsink and fan. unfortunately, when i turned it on, all the fans started, the power indicator lit, and the memory indicator on the board lit, but then it all shut down within 3-5 seconds.

i took out the peripherals, switched out the memory, and it persists. after trying it 4 times, it wouldn't power up at all. i went and sulked for a couple of hours, checked all the connections, took the motherboard out of the case, ran it on the nonconductive plastic with only the power supply, switched DIMMs, and the fans, and it did it again. i chcked the two switches for setting the speed of the motherboard (100, 133, 166).

i thought perhaps it was overheating, is this right? so i took took the heat sink off and noticed that the tab of adhesive attached the fan and heat sink only seemed to fuse to 20% of the the square on top of the cpu. did i miss something critical here? do i need to use something in addition to the adhesive that came with the heat sink and fan? should i try another heat sink before throwing up my arms and trying to return the cpu and motherboard without knowing which is the source of the problem?

any help would be very very much appreciated. thanks in advance.

[Budfred]

Welcome to http://www.pcguide.com/ubb/pcgubb.gif

If you actually used adhesive on the heatsink, that was the first mistake. It should have a thermal pad or thermal compound, not adhesive. If it was only covering 20% of the CPU die, it suggests that it wasn't applied properly or, more likely, the heatsink is badly cupped. You will probably need to lap the heatsink to get it flat... It is quite possible that you had overheating if you didn't have a good connection... Hopefully the CPU is not damaged, but that is a possibility...

[pave_spectre]

I dont know about others but I have found that the thermal compound that comes with the standard AMD heatsinks is extremely second rate and the bottoms of their heatsinks are poorly machined.
On my 1800XP after having problems with sautdowns and reboots, I discovered that part of the problem was the fact that the standard thermal compound had actually melted onto the PCB around the core and was no longer contacting the CPU core at all.
It is well worth it to replace the compund with Arctic Silver after lapping the Sink.

[jcrowland]

thanks very much for the advice.

i feared that the cpu could be damaged, i know these things heat up mighty fast. i just got the kit with the cpu and followed the directions, it had a mildly sticky adhesive of sorts that was stuck to the bottom of the heat sink, i removed the waxed paper and stuck it, per the the instructions.

i'll look into replacing that and removing the adhesive on the cpu with something plastic.

what is lapping though?

forgive my ignorance, i really haven't put together a pc in awhile and am not accustomed to such hot processors. (i started doing this back in the days of 8086's and kinda stopped around the p1's.)

[david eaton]

How to lap a heat sink (http://overclockersclub.com/heatsinklappingguide.php) .

Arctic silver is well known, and effective, but using it may invalidate the warranty on an AMD CPU.

David

[pave_spectre]

The sticky substance on the bottom of the heatsink wasnt by any chance pink in colour was it and sort of like plasticene or putty in consistency?
If so that is the worst thermal compound I have ever come across.

Arctic Silver will definitely invalidate the warranty on an AMD retail CPU(the ones that come with heatsink/fans), but personally I wont ever use their stock compound/heatsinks again.