Long story short...had my year-old overclocked i5 750 (3.0ghz on stock cooling) doing some video encoding the other night, and the machine shut off halfway through the process. Okay...fine...I figured it was getting too hot and maybe it just shut itself down to prevent damage. From here, the solution is simple...go into the BIOS upon restart and revert the OC...
...but it turns out I can't even get the thing to POST now.
I open up the case, and notice that when I hit the power switch, the four phase LED's on the mobo flick on for a split second and then turn off. Thing is...I can't repeat this without turning the PSU off, re-inserting the power cable, and flicking the PSU back on. Thinking it was a PSU problem, I did the paperclip test and tried it in another machine...it works fine.
Did a bench test with one stick of RAM + CPU + mobo only, then alternated with a different stick of RAM and then no RAM...problem persists. Reseated the CPU and HSF to no avail as well. Doesn't look like any of the CPU pins are burnt or charred...none of them are blackened or discoloured, anyways -- they look normal. No smells of burning coming from the mobo, either.
I've tried clearing the CMOS via jumper and that didn't do anything. I removed the CMOS battery about an hour ago and will replace it shortly to see if that does anything.
But a bizarre twist: I tried to power on the machine WITHOUT the 2x4 12v power connector and it stays on for about 2 seconds and flicks off and does this on an infinite loop until I switch the PSU off. Then as soon as I plug the 2x4 12v back into the mobo, it goes back to the original problem (on for a split second, and won't come back on unless I switch off the PSU and re-insert the power cord).
What's the deal? When the local computer shop opens up in a few hours, I'm going to bug them to see if I can borrow some components for a definitive diagnosis, but until then, I'd like to hear some input just to see what I'm in for here. I can provide more details if necessary.
Thanks.
edit: just replaced the CMOS battery. Nada.
edit 2: A solution...for now -- turns out it was a short...see post #3.
...but it turns out I can't even get the thing to POST now.
I open up the case, and notice that when I hit the power switch, the four phase LED's on the mobo flick on for a split second and then turn off. Thing is...I can't repeat this without turning the PSU off, re-inserting the power cable, and flicking the PSU back on. Thinking it was a PSU problem, I did the paperclip test and tried it in another machine...it works fine.
Did a bench test with one stick of RAM + CPU + mobo only, then alternated with a different stick of RAM and then no RAM...problem persists. Reseated the CPU and HSF to no avail as well. Doesn't look like any of the CPU pins are burnt or charred...none of them are blackened or discoloured, anyways -- they look normal. No smells of burning coming from the mobo, either.
I've tried clearing the CMOS via jumper and that didn't do anything. I removed the CMOS battery about an hour ago and will replace it shortly to see if that does anything.
But a bizarre twist: I tried to power on the machine WITHOUT the 2x4 12v power connector and it stays on for about 2 seconds and flicks off and does this on an infinite loop until I switch the PSU off. Then as soon as I plug the 2x4 12v back into the mobo, it goes back to the original problem (on for a split second, and won't come back on unless I switch off the PSU and re-insert the power cord).
What's the deal? When the local computer shop opens up in a few hours, I'm going to bug them to see if I can borrow some components for a definitive diagnosis, but until then, I'd like to hear some input just to see what I'm in for here. I can provide more details if necessary.
Thanks.
edit: just replaced the CMOS battery. Nada.
edit 2: A solution...for now -- turns out it was a short...see post #3.
Last edited: