[SOLVED] I plugged the floppy drive cable into fan port in motherboard

[Sowreen]

Hi. So basically the same old problem, I don't even know how this mistake just slipped past me but I have plugged the floppy disk cable into one of the sys_fans port.
I have a Gigabyte X470 mobo with a seasonic PSU. Got 3 custom fans installed on my pc and those 3 are connected to a controller. And I had a brain fart while thinking that the controller should be connected to a sys_fan instead of just in one molex cable. So I plugged everything and when I pressed the power button, nothing happened. I tried unplugging everything and connecting just the bare minimum and the pc still wont start. Then I switched the PSU. I mounted a Floston PSU low range to see if the problem was the PSU. It booted but a few seconds later smoke starts coming out of the Mobo. Unplugged fast everything, and the chip above the sys_fan connecter is burnt down I'll upload a photo. Luckily I had my GPU unplugged doing this. Now I left my PC at a specialized service for repair.
Please tell me that the only thing to repair is that chip and I don't have to buy a new Mobo or worse.
Image

 

[DRagor]

Generally, if the controller was connected to motherboard and NOT connected to PSU via molex cable, nothing bad should happen as the controller wasn't powered. Also, some controllers do want both connections (fan header for motherboard control and molex for power) so without knowing what kind of controller you use it's not possible to say if you even done something wrong.
Without even knowing what exactly was connected to the motherboard when you used the 2nd PSU no way of predicting what could be damaged. But there is high probability motherboard was defect from the very start. Seasonic PSU detected that there is some kind of short and refused to start, while the second PSU might not have the necessary protections and started fire.

 

[drea.drechsler]

Hi. So basically the same old problem, I don't even know how this mistake just slipped past me but I have plugged the floppy disk cable into one of the sys_fans port.
I have a Gigabyte X470 mobo with a seasonic PSU. Got 3 custom fans installed on my pc and those 3 are connected to a controller. And I had a brain fart while thinking that the controller should be connected to a sys_fan instead of just in one molex cable. So I plugged everything and when I pressed the power button, nothing happened. I tried unplugging everything and connecting just the bare minimum and the pc still wont start. Then I switched the PSU. I mounted a Floston PSU low range to see if the problem was the PSU. It booted but a few seconds later smoke starts coming out of the Mobo. Unplugged fast everything, and the chip above the sys_fan connecter is burnt down I'll upload a photo. Luckily I had my GPU unplugged doing this. Now I left my PC at a specialized service for repair.
Please tell me that the only thing to repair is that chip and I don't have to buy a new Mobo or worse.
Image

The fan controller chip was probably shorted internally. The original PSU would 'see' it and not start up (OCP at work?) while the next PSU didn't "see" or, or didn't care, so turned on anyway and released the smoke.

I've seen several motherboards where the fan controller was overloaded and burned up. All we did was cut out the bad chip (to remove any short to ground) and it would work OK, except that fan header didn't work of course. Hopefully that works for you...or maybe the shop can completely replace the chip and return full functionality.

 

[Sowreen]

Generally, if the controller was connected to motherboard and NOT connected to PSU via molex cable, nothing bad should happen as the controller wasn't powered. Also, some controllers do want both connections (fan header for motherboard control and molex for power) so without knowing what kind of controller you use it's not possible to say if you even done something wrong.
Without even knowing what exactly was connected to the motherboard when you used the 2nd PSU no way of predicting what could be damaged. But there is high probability motherboard was defect from the very start. Seasonic PSU detected that there is some kind of short and refused to start, while the second PSU might not have the necessary protections and started fire.

Yeah I know Seasonic PSU's got some protection that won't let you boot the system if they detect higher voltage than normal so I guess my PSU is fine. However I am worried about the motherboard. If I recall correctly the controller was connected to PSU via molex the first time when I used my seasonic PSU but I don't remember if it was connected when I used the second PSU

 

[TommyTwoTone66]

Hi. So basically the same old problem, I don't even know how this mistake just slipped past me but I have plugged the floppy disk cable into one of the sys_fans port.
I have a Gigabyte X470 mobo with a seasonic PSU. Got 3 custom fans installed on my pc and those 3 are connected to a controller. And I had a brain fart while thinking that the controller should be connected to a sys_fan instead of just in one molex cable. So I plugged everything and when I pressed the power button, nothing happened. I tried unplugging everything and connecting just the bare minimum and the pc still wont start. Then I switched the PSU. I mounted a Floston PSU low range to see if the problem was the PSU. It booted but a few seconds later smoke starts coming out of the Mobo. Unplugged fast everything, and the chip above the sys_fan connecter is burnt down I'll upload a photo. Luckily I had my GPU unplugged doing this. Now I left my PC at a specialized service for repair.
Please tell me that the only thing to repair is that chip and I don't have to buy a new Mobo or worse.
Image

You have to buy a new mobo. Even if the repair shop could somehow find out what part they needed to order, and somehow had a PCB reflow station capable of carrying out the repair, there is a global chip shortage at the moment impacting all chips, including the one you burned out.

sorry.

 

[DRagor]

Yeah I know Seasonic PSU's got some protection that won't let you boot the system if they detect higher voltage than normal so I guess my PSU is fine. However I am worried about the motherboard. If I recall correctly the controller was connected to PSU via molex the first time when I used my seasonic PSU but I don't remember if it was connected when I used the second PSU

Fine. That's completely understandable considering how much stress it is to see your PC catching fire. But it also means we can't really assess what and how badly was damaged. However if the controller was molex connected on 2nd attempt is almost surely got toasted. Other components, if you reacted quickly, might be okay. As for motherboard, the service shop certainly will be able to determine if the damage requires replacement. My guess would by 50/50.

 

[Sowreen]

Hi. If someone is still following this thread I came back with the final report.
Got my PC back last friday. Everything were fine eventually as the service guys just removed the damaged chip from the sys_fan 5.
I moved all the parts in a new case (Phanteks P360 white) and run some tests since then and the temperatures were normal as usual.
The only downside is that 2 of my 3 additional fans have lost their RGB lights probably when the electrical fault happened.