Hey guys - this might be a bit long, sorry it's rambling but I am just stumped.
So we have an editing machine:
i7 4790K
GIGABYTE GA-Z97X-UD7 TH REV.1.0 mobo
32 gigs of RAM
GTX 770
etc etc
Apparently, unbeknownst to me, it started acting up a couple of months ago. When you powered on, it would power cycle for about 20 minutes before finally coming on fully. And by power cycle, I mean it would start for a second or two then cut off and try again.
It never even got to POST and the LED on the mobo never even got a chance to light up.
We tried to isolate the situation by:
Removing motherboard from case and putting on cardboard to make sure no shorts were happening.
Removed all RAM and tested each stick.
Removed ALL components and just start up with nothing but the PSU, CPU/Cooler, and once with RAM and once without.
Nothing. Same thing. Bios light clicks on, machine powers off.
We reset CMOS as well.
Then I saw the BIOS switch and switched to the backup. Yay it seems to have worked! It gets into BIOS on the first bootup... no power cycling.
I take this moment to flash the Main BIOS to the latest revision and then bam... back to not working. Now, no matter how long you let it power cycle it will never come on.
Uh oh.
SO we order a new mobo replacement. Unfortunately it's expensive because it's old but we *need* that Thunderbolt capability.
Mobo comes in, replace all of the components... moment of truth.... same thing.
Powers on briefly. BIOS light comes on... *click* rinse repeat. Never gets to post.
We fiddle with some more cables... SURELY it's a short I think (although when we pulled everything out of the case that should have remedied that). Then voila... it comes on!
But we can never repeat the solution. If we reset the computer it's back to the same problem. Find another cable to fidget with and make it turn on? Great! Except it's just never repeatable so we can't say it's a short.
So now we're sitting here with a motherboard with no bent pins, a brand new PSU attached, a CPU sitting there with NO Cooler just to try it (what else do we have to lose) and it's still doing the same thing. Occasionally with this setup (aka CPU and no cooler) and the old PSU, if I pushed the mobo power cable just right it'd turn on and get to BIOS... but again not repeatable.
And this point... going through all of this (and I'm sure there's a lot I left out) it's *got* to be the CPU right? I just don't want to order a $350 part as a "test" and get stuck with it.
I don't know... my feeble brain is exhausted and just out of ideas.
We've also made sure no pins are bent and no thermal paste is accidentally where it shouldn't be.
Also all capacitors on both mobos seem the same.
So we have an editing machine:
i7 4790K
GIGABYTE GA-Z97X-UD7 TH REV.1.0 mobo
32 gigs of RAM
GTX 770
etc etc
Apparently, unbeknownst to me, it started acting up a couple of months ago. When you powered on, it would power cycle for about 20 minutes before finally coming on fully. And by power cycle, I mean it would start for a second or two then cut off and try again.
It never even got to POST and the LED on the mobo never even got a chance to light up.
We tried to isolate the situation by:
Removing motherboard from case and putting on cardboard to make sure no shorts were happening.
Removed all RAM and tested each stick.
Removed ALL components and just start up with nothing but the PSU, CPU/Cooler, and once with RAM and once without.
Nothing. Same thing. Bios light clicks on, machine powers off.
We reset CMOS as well.
Then I saw the BIOS switch and switched to the backup. Yay it seems to have worked! It gets into BIOS on the first bootup... no power cycling.
I take this moment to flash the Main BIOS to the latest revision and then bam... back to not working. Now, no matter how long you let it power cycle it will never come on.
Uh oh.
SO we order a new mobo replacement. Unfortunately it's expensive because it's old but we *need* that Thunderbolt capability.
Mobo comes in, replace all of the components... moment of truth.... same thing.
Powers on briefly. BIOS light comes on... *click* rinse repeat. Never gets to post.
We fiddle with some more cables... SURELY it's a short I think (although when we pulled everything out of the case that should have remedied that). Then voila... it comes on!
But we can never repeat the solution. If we reset the computer it's back to the same problem. Find another cable to fidget with and make it turn on? Great! Except it's just never repeatable so we can't say it's a short.
So now we're sitting here with a motherboard with no bent pins, a brand new PSU attached, a CPU sitting there with NO Cooler just to try it (what else do we have to lose) and it's still doing the same thing. Occasionally with this setup (aka CPU and no cooler) and the old PSU, if I pushed the mobo power cable just right it'd turn on and get to BIOS... but again not repeatable.
And this point... going through all of this (and I'm sure there's a lot I left out) it's *got* to be the CPU right? I just don't want to order a $350 part as a "test" and get stuck with it.
I don't know... my feeble brain is exhausted and just out of ideas.
We've also made sure no pins are bent and no thermal paste is accidentally where it shouldn't be.
Also all capacitors on both mobos seem the same.