What Could Have Caused This - PSU Cable Burn

[amjedm]

My nephews PC kept restarting and he could smell burning so he opened it up to have a look. Just about managed to remove the connector from the motherboard as it seemed like it was glued in.




The computer was plugged in to a surge protector so I haven't a clue what caused it.

Any ideas?

Thanks.

[Clunk]

My guess would be fire. Hot, smokey, burney, fire.

Seriously though, was it a q-tec?

[charleski]

The scorch-marks are on the +5V pins, if that's any use.

[Giraffe]

Usually due to significant current and poor connections - used to get it at work and I could sometimes tell what was wrong from the smell (melamine connector block smells like fish!).
If the sockets in the plug had gone 'soft', they'll get warm; this will 'soften' them more and the temperature will rise...smoke!

[amjedm]

My guess would be fire. Hot, smokey, burney, fire.

Seriously though, was it a q-tec?

LOL

, me Q-Tec you gotta be joking

It was a FSP350-60PN (PF), rotary knob on the back to reduce fan speed but it should speed up if the PSU is overheating.

I did swap the fan for a quieter one but that shouldn't have made a difference?

Specs
Athlon XP2600
Asus A7V600
2 Optical Drives
512MB RAM
2 120mm Fans
Radeon 9600 Passive
2 WD Sata HD - don't know capacity

[amjedm]

Usually due to significant current and poor connections - used to get it at work and I could sometimes tell what was wrong from the smell (melamine connector block smells like fish!).
If the sockets in the plug had gone 'soft', they'll get warm; this will 'soften' them more and the temperature will rise...smoke!

Wouldn't the Surge Protector limit effect of the current?

[fat jez]

That looks as though the 5v line has shorted out somewhere. The motherboard is probably toast too

Cheers,
Stephen

[amjedm]

That looks as though the 5v line has shorted out somewhere. The motherboard is probably toast too

Cheers,
Stephen

I agree - the mobo may have died , the motherboard connector also has a burn mark

[peterb]

Could have been that the plug wasn't pushed fully home or some of the 5V pins had become dislocated from the holder. Result would be higher contact resistance - heat, melting - burn. If that is the case Mobo might have survived.

Other scenario is a failed component on the mobo leading to excessive current in which case the mobo probably has had it - but the CPU/memory may have survived.

[amjedm]

Could have been that the plug wasn't pushed fully home or some of the 5V pins had become dislocated from the holder. Result would be higher contact resistance - heat, melting - burn. If that is the case Mobo might have survived.

Other scenario is a failed component on the mobo leading to excessive current in which case the mobo probably has had it - but the CPU/memory may have survived.

Thank you.

I believe memory is ok as it's being used in another system.

Don't have a spare Socket A motherboard to test the Athlon XP 2600 in.

[vaughan]

Wouldn't the Surge Protector limit effect of the current?

no, the surge protector is to protect the appliance from mains surges (ie. sometimes mains power spikes making the mains supply quickly send a surge of more than 230v for a split second, or if lightning strikes, it can send dangerous mains surges), usually you get surges when switching equipment on/off.

but the surge protection offers no protection to the pc other than as a mains filter.

[Agent]

Wouldn't the Surge Protector limit effect of the current?

Nope
A surge protector does only that one thing - stop surges going to the PSU (They help regulate the voltage going to the PSU). Although current and voltage go hand in hand (OHM's law, ect...), most only have the circuitry to deal with the voltage side of things (of course, you should have a fuse to stop any major current issues )
Without going into the specifics of them, it wouldn't have made a difference in this situation as any current issues would have happened from the PSU to the board. At this point, the PSU would be regulating the DC voltage going to the board (The transformer in it will be doing the AC/DC conversion)

It could be a short. Most PSU's have some basic over-current circuitry to stop things like this happening though. The only other times I have seen it is with cheapo PSU's that have very thin wiring and people put them in a high powered system, or where the cap's on the motherboard have gone (Have a look for buldging caps on it)

[Pob255]

Did you do any 7v fan mods? they involve useing the +5v as an earth and feding power back down it which is none to good for the PSU.
Which I wonder about when you said

It was a FSP350-60PN (PF), rotary knob on the back to reduce fan speed but it should speed up if the PSU is overheating.
I did swap the fan for a quieter one but that shouldn't have made a difference?

although any other other 7v fan mods could of caused problems.

So could the connector as peterb said

Could have been that the plug wasn't pushed fully home or some of the 5V pins had become dislocated from the holder.

I'll expand on this slightly, had a problem with a decent cheiftech PSU recently, one of the metal connectors on the PSU 20pin motherboard plug was bent inwards slightly, so the pin in the socket wouldn't go in but just pushed and bent the conector, they were touching but the contact was bad (I never checked what it did to the voltage/ampage) but the whole pc became as unstable as heck.
Put in a new PSU and it was happy.

[IAmATeaf]

A poor connection or as others have said a mobo which was causing the rail to short would be prime candidates.

[herulach]

Its also worth opinting out that it could have been a surge, the majority of 'surge protectors' (i.e. anything not attached to a production grade ups) is likely to be pretty cheaply made, and die after maybe 1 or 2 surges. After that its just an expensive 4 gang

[amjedm]

Did you do any 7v fan mods? they involve useing the +5v as an earth and feding power back down it which is none to good for the PSU.
Which I wonder about when you saidalthough any other other 7v fan mods could of caused problems.

Was using a Sunbeam Rheobus but that shouldn't have affected it.