How can a GPU cooler kill 2 motherboards?

[KnickNut3]

Hello. This is somewhat of an ongoing development (without much help) in tech support, but I figure the guys in here would be the experts on GPU-related stuff:

I'm about to throw in a new PSU, CPU fan, and Iceberq 4 Pro for my GF4 Ti4400 fan that broke. I replace them and hit the switch, and soem weird things happen. My EP-8RDA+ just flashes "FF" on the LED, and while that usually means everything's fine, it has to go through some other displays to show it's booting. Suddenly this MB will only post that and has no chance of booting. As I begin to test it more, other time it doesn't try to initiate booting, and I just start smelling burning. Also, the fan power ports on the top half of the motherboard stopped working right away, but the bottom port's fine.

I rip apart another EP-8RDA+ machine to make sure my CPU wasn't the thing burning. I switch it in and it's fine. I switch out PC #2's GF4 MX and pop in my GF4 Ti4400. All of a sudden it won't boot. I switch it out immediately and put the MX back in--only "FF." No power problems or burning smell, but dead none the same.

I've reset the BIOS on both machines, let them cool, etc etc. All I did on my GPU was rip off the old one, slop on some Artic Silver 3, and put on the new one and connect the power. Could I have shorted it out? Completed a circuit or something? Might I have disrupted one of the (whatever one of those cylindars on the card are... circuits, capacitors?)? Could that cause problems like this? Please point me in a direction--how a safe fan upgrade kills 2 systems is beyond me.

[Siliconjunkie]

It sounds like the MX's fan has a short in it. Shorts will cause excessive current draw (smoke/burning) as well as damage things in the power circuts that feed them.

[KnickNut3]

The MX one? The Ti4400 is the one I put the new fan on, and that was in the machine when both PCs went down... I don't think the smoke smell was coming from the card, though--it could be shorting out the motherboard?

[Siliconjunkie]

My bad, got confused. Whichever is killing them.

The smoke smeill could be coming from the fan or the motherboard. It isnt shorting it, just drawing too much current through it. The traces on the motherboard can only handle so much. Too much current will burn them up and they will not pass current anymore.

[KnickNut3]

So you think both MBs are not salvigable? Should I dump the video card too? This is a brand new cooler--are they responsible for damages?

[Xtreeme]

If the draw was on the negative side of power -its toasted. Mobo and psu dont like any power draw on neg side in ATX form factor.... Also dont ever attach a fan speed regulator (Rheostat really) on the - side of power you'll smoke the psu and mobo fast. Same reason. Just for future refrence. My guess is either you damaged Video card board removing HSF or you put WAY too much AS3 on it and shorted stuff out. With traces so close you should use AS ceramic which has no conductive OR capacitive properties.

[KnickNut3]

Putting it on the side of power?

[Xtreeme]

The yellow wire from PSU that goes to each device an ends in what is called a "molex plug". THis is the wire you should attach any speed regulating devices too. Potentiometers/rheostats samthing. Or ressistors or diodes to lower current (another trick). Putting these components on the - BLACK wire will draw more on the - leg of psu. All the neg legs are attached at the psu. ATX spec doesnt take much power draw on - leg. So easy to overcurrent it. This can fry mobo-psu-and any or all devices attached. Even stuff in the usb ports. Very bad stuff. Thats why I mentioned-just for future pc ventures. Dont attach speed controler on black wires ever! Hehe.

[jmichna]

Originally posted by Xtreeme
The yellow wire from PSU that goes to each device an ends in what is called a "molex plug". THis is the wire you should attach any speed regulating devices too. Potentiometers/rheostats samthing. Or ressistors or diodes to lower current (another trick). Putting these components on the - BLACK wire will draw more on the - leg of psu. All the neg legs are attached at the psu. ATX spec doesnt take much power draw on - leg. So easy to overcurrent it. This can fry mobo-psu-and any or all devices attached. Even stuff in the usb ports. Very bad stuff. Thats why I mentioned-just for future pc ventures. Dont attach speed controler on black wires ever! Hehe.

Good tip, Xtreeme!!!
I din't know that.
Thanks,
jmichna

[KnickNut3]

Ah, ok.

I think that's one mistake I'm sure I DIDN'T have the chance to make