My motherboard set on fire

[Shodan___]

Pc has been problem free for months, I’m playing a game and suddenly the pc shuts off completely. I hit the power switch and nothing happens.
Try the usual unplugging and plugging cables etc, leave it for a while in case overheating, still nothing. Try the self test on PSU, nothing

Ok, PSU is dead. Buy a new PSU. CORSAIR rmx850. Plug it in, I have power, starts booting. Amazing! 2 seconds later, shuts off again, reboots itself, I hear a whoosing noise like wind and see an orange glow from inside the case. Uh oh. I go to unplug it from the wall but it shuts down itself, I’m panicking, it boots up again, again the noise and this time I see what looked like a jet of flame coming from near the 2x4 power pins at the top of my mobo.

GPU, sound card and 2 ram sticks are all burned, they still stink a day later and GPU has physical burn damage.

Strangely, I can’t see any damage on the actual motherboard itself, but it has thermal armour so can’t actually see underneath it.

1) how did this happen?
2) as the PSU is brand new, I can’t smell any burning from it, it shosukd be safe to use in a new PC right?
3) everything not burnt should be fine to use again? Cables, cards, disks etc

The specs were;
980 TI
2600K cpu
16gb Corsair vengeance ddr3
Corsair ax850 PSU

 

[edscdk]

1) something went wrong
2) your guess is as good as mine personally it at least test on a crappy system for a while even then it might not be safe
3) not necessarily test but individually on a crappy system

Sounds cool any pics?

 

[singularity]

Logic says the psu was the original problem, logic also says the new psu was the final problem.

 

[Shodan___]

From doing some research it sounds like my ax850 shut itself off to protect my pc from a short circuit. Apparently they have safety features that ‘deactivate’ the PSU if powering on would cause damage to the system. That could also cause the self test to give no result as it looks to be dead.

When I plugged in the new PSU it just happily supplied power and the short circuit happened.

Does this sound likely?

 

[singularity]

From doing some research it sounds like my ax850 shut itself off to protect my pc from a short circuit. Apparently they have safety features that ‘deactivate’ the PSU if powering on would cause damage to the system. That could also cause the self test to give no result as it looks to be dead.

When I plugged in the new PSU it just happily supplied power and the short circuit happened.

Does this sound likely?

maybe

 

[Danny75]

Strangely, I can’t see any damage on the actual motherboard itself, but it has thermal armour so can’t actually see underneath it.

Find out how to remove it and have a look.

Had similar happen with faulty GPU. System powered off safely while playing a game. Refused to start. Taking GPU out did the trick. Re-tested GPU in different system out of curiosity, and it (some mosfets) immediately caught fire.

Which 980Ti was it?

 

[Double07]

maybe

Helpful.

 

[singularity]

Helpful.

Also

 

[DoneADougalOnSofa]

My guess would be VRM failure- one that let an excessive current flow into the board.
If you're lucky, the CPU might have survived... Sounds like a bit of a mess aside from that, though.

I had the VRMs let go on a Gigabyte Z87 board, luckily it went the other way and just switched itself off, never to boot again- just had the board power LED flickering, but no life other than that. Components (bar the mobo, obvs) all survived.

 

[Shodan___]

My guess would be VRM failure- one that let an excessive current flow into the board.
If you're lucky, the CPU might have survived... Sounds like a bit of a mess aside from that, though.

I had the VRMs let go on a Gigabyte Z87 board, luckily it went the other way and just switched itself off, never to boot again- just had the board power LED flickering, but no life other than that. Components (bar the mobo, obvs) all survived.

Sounds like that could be what I saw. The CPU looks fine, no visible damage and no burnt smell. Just realised I didn’t mention the mobo. It’s a ASUS Sabertooth P67

Find out how to remove it and have a look.

Which 980Ti was it?

EVGA 980TI SC+

 

[EsaT]

this time I see what looked like a jet of flame coming from near the 2x4 power pins at the top of my mobo.

Strangely, I can’t see any damage on the actual motherboard itself, but it has thermal armour so can’t actually see underneath it.

Likely CPU VRM short circuited.
Though that stupid cooking cover put there by marketroids and suits might have also baked something else dead, like VRM's controller starting some chain reaction.
Because all it ever achieved was to prevent heat from dissipating into air.


Motherboard is certainly dead.
And CPU was definitely in risk zone, because depending of what caused failure VRM might have let some 12V through before shorting.

Also if there was some flame literally hitting other parts those might have gotten damaged by heat/have some soot etc deposits on them possibly creating shorts.
Using oversized PSU increases risks from short circuiting parts, because it takes higher current to trigger PSU's protections.
And with big enough PSU resistance of wiring, connectors and other circuitry might limit current below triggering threshold of PSU.
(causing continuous short circuit until shorted part simply burns away from heat)

Drives should be good.
Unless motherboard shorted somehow sending too high voltage to data lines.
PSU shuts itself down if shorting load causes deviations in output voltage.

And unless burnt somehow cables are good.

 

[Double07]

Also

less so

 

[an0nym0us]

When you swapped PSUs, did you also change all the PSU cables?

General rule of thumb is, always use the same cables that came with that specific PSU (unless you're certain the cables are interchangeable).

Cables from one PSU are often not interchangeable with those from other PSUs (even it's the same PSU brand). Please see this rather complicated Corsair PSU cable compatibility chart for reference:
https://www.corsair.com/uk/en/psu-cable-compatibility

I've heard of instances where people have bricked multiple SATA drives by using the wrong PSU cables, but wasn't as bad what OP experienced, so may not be applicable in this thread.

Apologies if none of this info applies to you OP, but hopefully others find it useful when changing modular PSUs.

 

[Apone70]

do you have pictures of the damage?