[SOLVED] At a loss, need help powering up PC

[MonsieurDJ]

I've got a computer with boot problems and I can't for the life of me figure out what's wrong with the thing. It worked fine for a couple of years and one morning it powers up for a second (lights and fans come on), than shuts down, automatically powers up again, getting stuck in this loop.
Specs:
Fatality b85 killer mobo
I5-4460 cpu
seagate 550watt psu
2x8gb kingstong hyperX ram

It would seem to be a shorting problem or faulty components. So far I've tried unplugging all components one- by-one , running bare-minimum (psu, mobo, cpu), and all configurations imaginable to check for faulty parts. Problem persists.

I've tried a different PSU (same), tried this PSU on another pc (no problem).

Shifted Ram, 1 bank of RAM, no Ram (all the same). Tried running mobo out of case (same problem still). My conclusion at this moment is either faulty mobo or faulty cpu but I've got no way of checking because I've got no spares.

As a last trick I tried clearing the cmos by way of jumper. With the jumper in 'clearing cmos' position nothing happened on powerbutton (no lights, no fans) but after removing the jumper it automatically powers on and keeps running. However, I can't get an image.

Since the jumper trick is repeatable I've tried again and again, disabling GPU, trying onboard GPU (vga en dvi), all with no image. However, since it keeps running after the jumper trick a short seems unlikely and since it keeps running the faulty cpu/mobo theory is also becoming less likely. Long story short, HELP!

 

[clutchc]

Wait. You ran the PC with the CMOS grounded out? Is it possible you killed the CMOS chip?

 

[MonsieurDJ]

Wait. You ran the PC with the CMOS grounded out? Is it possible you killed the CMOS chip?

Don't know. I tried to boot with jumper in reset mode. Pc did nothing (no lights, no fans etc. Then removed pin to reset to normal mode (without shutting down PSU first, I know, dumb) and it powered up and kept running but with no screen. Since it kept running I tried this trick again to see if I could get an image from the onboard GPU instead after uncoupling GPU. No succes but similar results.
But if I understand you correctly, running without the jumper might fry the chip? In that case chances are the mobo is screwed. I'm still puzzeled about the rest of the situation however.

 

[clutchc]

I don't know if that will "fry" the chip. But it will power the chip with some circuits grounded out. That may cause the CMOS chip to fail. I don't know... never tried it. But on modern boards I would hope there would be a failsafe mechanism to prevent that type of user error.

It sounds like you already tried breadboarding the bare bones system outside the case. Just CPU/cooler, RAM, PSU, iGPU, PSU, monitor... and shorting the pins the start button would go to. No luck, right?

 

[MonsieurDJ]

I don't know if that will "fry" the chip. But it will power the chip with some circuits grounded out. That may cause the CMOS chip to fail. I don't know... never tried it. But on modern boards I would hope there would be a failsafe mechanism to prevent that type of user error.

It sounds like you already tried breadboarding the bare bones system outside the case. Just CPU/cooler, RAM, PSU, iGPU, PSU, monitor... and shorting the pins the start button would go to. No luck, right?

Nope, no results. In the end I got fed up with the whole thing, bought a new board (and cpu and ram while I was at it) and now have a functioning pc again. While I've actually put my money on a bad board, I can't shake the feeling that there must be something I have overlooked rather than it just being a bad board. At the same time, this build had been cursed right from the get go, with GPU & PSU problems and a whole host of unidentifiable problems that led to buying new components (GPU & PSU). Every time I thought I fixed something, something else popped up after a period of flawless use, ending with this bad board business.

 

[clutchc]

What board, CPU and RAM did you get to replace the other one?
If you still have the bad system, you can always experiment with it. If you could at least get it to boot to BIOS by bread-boarding it, you might be able to flash the BIOS.

 

[dstln]

Wow yeah, that situation sounds frustrating. I'd venture to guess motherboard failure of some sort, do you see any issues on the front or back of the motherboard? Usually a CPU wouldn't just die if it's been sitting there, but you could check and see if any pins got damaged somehow, especially if you removed it around the time of failure for any reason.

If you got the motherboard within 3 years, it looks like it may still be under warranty for you.