Hardware Help me fix my laptop's fan please?

[Wizardkoer]

Okay, so I have a Samsung ATIV Book 5 NP540U4E-K01AU and, a relatively common problem with the BIOS, that the system fan doesn't work. This isn't a hardware issue but a software one, as I have seen many with this issue after updating BIOS. There is a way to downgrade the BIOS to fix it, but unfortunately it didn't work for me. Anyways, I want to directly power the fan, so it's on whenever I connect the power. I have many useless usb cords so I was thinking of connecting that directly to my fan so I can plug it in when I want to start my system. My laptop allows me to use it without the fan, as it's an ultrabook, but after using it a while, it gets a bit hot and my CPU temps can get high so yeah. I want the fan to run all the time directly using a usb cable. Can anyone help me out as in how to connect it. I'm a noob so yeah .

 

[FAST6191]

What Voltage is the fan? If it is a 12V fan, and I would be surprised if it was not*, then tickling it with 5V from the USB port is not going to do you much good. You can slice up the cable and use the very nice wires inside it to help you but alone it is not going to do much. The fan will hopefully have a label on it saying what Voltage it wants.
Otherwise fans/motors are usually pretty simple -- you will probably have three wires at most and if you are lucky then only two. If it is two wires then one will be positive and one will be negative, for a lot of fan designs it will not blow it up to be connected the wrong way but it will spin the blades the wrong way to get the air flow you want so best to make sure it is what it is. The third wire is then usually a speed sensor of some form so it can throttle it however it will (usually so called pulse width modulation but let us not go there right now). For a normal PC you have 12V capable of supplying more than enough power basically everywhere in the machine, laptops can get slightly more tricky.

*I say having not paid attention to laptop fan electrical specs for a few years now.

Anyway once you have figured out what wire is what then you need to find a suitable voltage source to pull from. Not to mention if you are wiring it to USB it involves slicing some wires and soldering wires (or even twisting them together) where this will probably involve soldering to the motherboard.

If it is 5V then here is a USB pinout http://pinouts.ru/Slots/usb_pinout.shtml
Assuming your sacrificial cable has the traditional colours then red is positive and black is negative.

If it is 12V then probably better to find someone that knows electronics. It will be trivial for them but above I left out how to find the ground and if that is not something you immediately know how to do then starting on an $800 laptop is not the best plan.

Either way though when you are cutting wires I would make sure you leave enough so you can undo it later if Samsung decide to get it in gear and fix the issue.

 

[Wizardkoer]

What Voltage is the fan? If it is a 12V fan, and I would be surprised if it was not*, then tickling it with 5V from the USB port is not going to do you much good. You can slice up the cable and use the very nice wires inside it to help you but alone it is not going to do much. The fan will hopefully have a label on it saying what Voltage it wants.
Otherwise fans/motors are usually pretty simple -- you will probably have three wires at most and if you are lucky then only two. If it is two wires then one will be positive and one will be negative, for a lot of fan designs it will not blow it up to be connected the wrong way but it will spin the blades the wrong way to get the air flow you want so best to make sure it is what it is. The third wire is then usually a speed sensor of some form so it can throttle it however it will (usually so called pulse width modulation but let us not go there right now). For a normal PC you have 12V capable of supplying more than enough power basically everywhere in the machine, laptops can get slightly more tricky.

*I say having not paid attention to laptop fan electrical specs for a few years now.

Anyway once you have figured out what wire is what then you need to find a suitable voltage source to pull from. Not to mention if you are wiring it to USB it involves slicing some wires and soldering wires (or even twisting them together) where this will probably involve soldering to the motherboard.

If it is 5V then here is a USB pinout http://pinouts.ru/Slots/usb_pinout.shtml
Assuming your sacrificial cable has the traditional colours then red is positive and black is negative.

If it is 12V then probably better to find someone that knows electronics. It will be trivial for them but above I left out how to find the ground and if that is not something you immediately know how to do then starting on an $800 laptop is not the best plan.

Either way though when you are cutting wires I would make sure you leave enough so you can undo it later if Samsung decide to get it in gear and fix the issue.

Ahh thanks for your help but I seem to have solved the issue. The BIOS was screwed and I FINALLY managed to downgrade then reupgrade the BIOS and now it's working like a beauty. I also gave the fans a little clean. My laptop ain't getting hot any more and everything's running sweet. Thanks for your help anyway, I will probably directly connect it to run it at 100% all the time probably next weekend. And I will check it out if it is a 5v or a 12v fan. It has three wires.