Might have broken my motherboard. Help?

mrluckypants96

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Not really sure if this is the best place to put this, but it seems my motherboard might have gotten fried from a short circuit. Here's what happened: I unplugged the control wire from my CPU cooler, plugged it back in slightly misaligned, and the system shut off and wouldn't turn back on.

When the 24-pin connector on the PSU is started, the PSU starts right up, fans connected to my Sentry Mix 2 spin, fans and pump on my EK Predator spin, and the CPU can spins. Crucial information here is that the CPU cooler is a Phononic Hex, which has a USB link to the motherboard, a 6-pin PCIe power connector from the PSU, and the 4-pin fan header which goes from the cooler to the PWM splitter on the Predator. The Predator has a SATA power link to the PSU and a 4-pin fan connector (without the 12V and ground, just the tach readout and PWM control wires).

I accidentally put the fan cable connecting the Hex and the Predator off by one wire, so the PWM wire was connected to the tach pin, the tach wire was connected to the 12V input pin, and the 12V wire was shorted with the ground pin. I'm not sure how it caused damage as the cooling devices are only connected to the motherboard by a USB cable on the Hex and the PWM/tach wire on the Predator, but in any case the system won't boot when everything is hooked up normally. Power button does nothing, I don't even get the fan twitch I got the last time I had a device short out (failed NZXT Hue).

Can anyone shed some light on the situation?
 

rgMekanic

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I'm not familiar with that cooler, sounds a little ridiculous to me heh, but if you supply power to a fan header, you can cool a board for sure.

EDIT: looked up that cooler... dafuq does it need a 75w 6 pin PCIE connector for?! With all that juice, + the 5v from the USB header, depending on the wiring layout of that thing, it could potentially shove a lot of juice into a fan header.
 

mrluckypants96

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It's a TEC cooler, so it needs a good power supply. The USB power is for software connectivity. I got it because I wanted as much cooling power as I could get, with a very small space. It also compliments the TEC coolers I have in my 2P "Server". It appears, however that the PCIe power for the TEC and the power for the fan are separate. Experiments have shown that the fan spins with the fan connector attached but not with only the PCIe power attached. I was able to do some tests and it appears to short circuit shutdown whenever the ATX connector is in the motherboard, won't even give a power good signal. Everything else is unplugged.

Edit: Wait. With the system running, removing the fan cable from the Hex kicks the fan to full speed. With the ATX cable shorted, it spins only with the fan cable attached. Im not sure how the wiring works in it I guess.
 

mrluckypants96

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depending on the wiring layout of that thing, it could potentially shove a lot of juice into a fan header.

The part that confuses me is that I shorted the input of the cooler. It takes in PWM signal and 12V from the motherboard (or the PWM splitter in my case) and sends back the tach signal. The 6-pin shouldn't be sending power back along that line. The cable connecting the PWM splitter and the motherboard doesn't have the 12V or ground cables, just the PWM and tach lines, so I don't see how any power actually got to the motherboard.
 
D

Deleted member 133315

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Reset the bios, make sure everything is plugged in correctly and see if that works.

Edit,

He is using a tec, your mobo is fried.

Try with a normal cpu cooler and see if you can get the board to post, reset bios, make sure you dont have any grounding issues and everything is plugged in correctly, if it boots then you know its the tec thats at fault, if it doesnt boot then you could also try removing the mobo battery for a few minutes whilst resetting the bios and see if that kicks it back into life.
 
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mrluckypants96

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Reset the bios, make sure everything is plugged in correctly and see if that works.

Edit,

He is using a tec, your mobo is fried.

Try with a normal cpu cooler and see if you can get the board to post, reset bios, make sure you dont have any grounding issues and everything is plugged in correctly, if it boots then you know its the tec thats at fault, if it doesnt boot then you could also try removing the mobo battery for a few minutes whilst resetting the bios and see if that kicks it back into life.

Alright, bios reset and battery pull did nothing. I've pulled the board from the case, disconnected everything except the ATX connector, and used a backup PSU. When I turn on the PSU, the system won't turn on, PSU fan doesn't spin, etc. No signs of life, EXCEPT, the X79 chipset heatsink heats up dramatically. I wouldn't think it possible given that there's supposedly no power coming from the PSU.
 

mrluckypants96

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Update: I plugged in the system on a breadboard and shorted the power good wire to ground manually. The fan on the PSU spun up, the motherboard gave a POST beep, and then came the sound of frying bacon and the magic smoke came pouring out of the SATA ports. If it wasn't dead before, it is now.

Given the power supplied during the short was from a SATA power harness and the failure is somewhere in the chipset/SATA controller, I fear for the lives of my drives.
 
D

Deleted member 133315

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If I was you, I would not use that powersupply for that pc again until it was tested, just so you can rule that out as the cause.

Test you hard drives in another setup along with video card etc, but I would not hook anything upto the psu that was in the system with the fried mobo just incase it was the psu that was the cause.

Its probably a short somewhere on the board as you did mention you messing up a wire earlier, but its always shit when hardware dies on ya :(

If its the hard drives in your sig, pray that it hasnt fucked up roughly 9TB of data, thats wrist cutting time.
 
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mrluckypants96

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If I was you, I would not use that powersupply for that pc again until it was tested, just so you can rule that out as the cause.

Test you hard drives in another setup along with video card etc, but I would not hook anything upto the psu that was in the system with the fried mobo just incase it was the psu that was the cause.

Its probably a short somewhere on the board as you did mention you messing up a wire earlier, but its always shit when hardware dies on ya :(

If its the hard drives in your sig, pray that it hasnt fucked up roughly 9TB of data, thats wrist cutting time.

Yeah, I tested the PSU with another system and it all worked fine. The breadboard tests were done with a spare PSU I keep around specifically for testing things. Luckily most of my drives are in an external drive box, waiting on cables to connect them to my LSI HBA card. Still means my highly customized OS drive and a drive full of school and work files are at risk.
 

Nenu

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Moral of the story, dont live plug fan connectors to a mobo.
 

Wade88

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Yep, I saw my friend do that in high school and he wrecked his sweet opteron build doing that but not with a TEC, just a regular 92mm fan.
 

mrluckypants96

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I have to ask....

Were you moving the plugs around with the system powered up?

.

Technically yes, but it was only a fan connector input.

Moral of the story, dont live plug fan connectors to a mobo.

That's the part that confused me. The cooler wasn't plugged into the mobo. It was wired to a PWM splitter powered by a SATA power connector. The only connection paths to the motherboard from those components would be through the USB cable, the PWM/tach wire from the splitter, or through the SATA cables from the drives.

Yep, I saw my friend do that in high school and he wrecked his sweet opteron build doing that but not with a TEC, just a regular 92mm fan.

Ouch. Power supplies really need to react quicker to shorts it seems.
 

Nenu

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That's the part that confused me. The cooler wasn't plugged into the mobo. It was wired to a PWM splitter powered by a SATA power connector. The only connection paths to the motherboard from those components would be through the USB cable, the PWM/tach wire from the splitter, or through the SATA cables from the drives.
12V is present.

Ouch. Power supplies really need to react quicker to shorts it seems.
They do if its going to harm the PSU. PSU protection will not help low current shorts, its not possible.
A fan connector and wires will burn up before enough current can flow to trip a PSU.
 

Spartacus

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Technically yes, but it was only a fan connector input.

[snip]

Ouch. Power supplies really need to react quicker to shorts it seems.


That's what I thought.... don't do that. I've been in electronics and IT for many years, that's something that you learn
very early on. Don't go messing with connections on powered electronics.

There are exceptions like USB and hot pluggable drives, etc. but in general don't do it. People used to think the PS/2 type
keyboard/mouse connections were hot pluggable like newer USB and they are not. That used to lock up systems and blow
surface mount fuses (sometimes chipsets) on motherboards all the time.

As for "Power supplies really need to react quicker to shorts it seems.", lol.... no.

It may not have been a direct short for one thing. When you connected it wrong, it setup a circuit that damaged parts by
running current through the parts in ways it should not be, but it was not seen as a direct short or too heavy of a load.

There is a better chance the PSU may have seen a problem at power-up if it was off, but there is no guarantee of that.
You can't rely on the PSU to stop you from destroying your equipment, it doesn't work that way.

Sorry you lost the mobo.

ETA: Also, slow down and don't rush though making electrical connections. Take your time and
double check that what you are doing is correct.


.
 
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mrluckypants96

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That's what I thought.... don't do that. I've been in electronics and IT for many years, that's something that you learn
very early on. Don't go messing with connections on powered electronics.

There are exceptions like USB and hot pluggable drives, etc. but in general don't do it. People used to think the PS/2 type
keyboard/mouse connections were hot pluggable like newer USB and they are not. That used to lock up systems and blow
surface mount fuses (sometimes chipsets) on motherboards all the time.

As for "Power supplies really need to react quicker to shorts it seems.", lol.... no.

It may not have been a direct short for one thing. When you connected it wrong, it setup a circuit that damaged parts by
running current through the parts in ways it should not be, but it was not seen as a direct short or too heavy of a load.

There is a better chance the PSU may have seen a problem at power-up if it was off, but there is no guarantee of that.
You can't rely on the PSU to stop you from destroying your equipment, it doesn't work that way.

Sorry you lost the mobo.

ETA: Also, slow down and don't rush though making electrical connections. Take your time and
double check that what you are doing is correct.


.

I often treat anything that has only a power connection and no data connection (fan connectors, molex/SATA powered bay devices) as hot-pluggable. I should probably stop doing that.

The PSU did power down after a few seconds. What kept happening is that the fan controller in the motherboard kept ping-ponging back and forth between two fan speeds as temps changed. While the 92mm buried in the center of the cooler was silent at those speeds, the much bigger and faster EK Vardar fans were clearly audible and were irritating me. My idea was to temporarily unplug the fan connector to force the fan to full speed and cool the system down below the level the system had equalized itself at. When I plugged it back in, everything was fine for a second or two, then I smelled that hot electric smell, then the PSU shut off and wouldn't turn on as long as it was plugged into the motherboard.

In my defense, the cable doesn't have anything keeping it from being connected incorrectly. Most fan headers/cables have the key and groove so you can only plug it in the right way or not at all.

I've confirmed that the TEC system still works and both drives survived. But I haven't been able to test the CPU and RAM yet.

12V is present.


They do if its going to harm the PSU. PSU protection will not help low current shorts, its not possible.
A fan connector and wires will burn up before enough current can flow to trip a PSU.

I get that 12V current is present. I'm just confused as to how it got to the motherboard. I would've thought that it would've gone back along the ground wire and tripped the PSU once the current got too high. I don't see any burned wires or traces on any components. I also confirmed that the connector that was shorted is exclusively a power input. Fans won't run when connected to it and multimeter shows no voltages across any pins when the unit is powered up.
 

Nenu

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I get that 12V current is present. I'm just confused as to how it got to the motherboard. I would've thought that it would've gone back along the ground wire and tripped the PSU once the current got too high.
The motherboard has 12V out, a PWM sensor circuit and ground rail.
12V, ground or elevated ground voltage on the connected wire to the wrong pin could cause enough current to flow to fry something causing a fault to be detected on the motherboard.
By then its too late.

The PSU didnt detect a short circuit because there wasnt one it could detect, we have covered this.
The shutdown was caused by the motherboard no longer signalling that power should be allowed.
This is why it didnt power up after.

I don't see any burned wires or traces on any components. I also confirmed that the connector that was shorted is exclusively a power input. Fans won't run when connected to it and multimeter shows no voltages across any pins when the unit is powered up.
The motherboard did its job cutting the power before a fire hazard occurred.
There is only so much protection you can build into a product before cost, complexity or bulk become problems.
The common sense approach to dealing with live circuits is not to plug things in unless designed for that purpose when live.
You took the risk and didnt fall foul of a manufacturing defect or unfortunate side effect, you made a catastrophic error a) live plugging b) incorrectly live plugging.
 

Wade88

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In the future you shouldn't mess with the wires in your case at all unless it's off and unplugged , press the power button a few times, then manipulate wires, replug psu, turn the switch and if it works put the side panel back on.
 
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