Replacement Laptop Fan Not Starting

[AndrewHylands]

I was experiencing multiple issues with my Acer Aspire 5750G so have now replaced the motherboard & processor. The laptop works perfectly now except the fan does not seem to start, possibly the reason why things went faulty. I bought a new fan but cannot get it to start with either motherboard.

I'm pretty much out of ideas on this one on what to try next. The bios is fully updated, the fan power supply is connected but I don't think the laptop is recognising it. Not sure if I need to do something else? Could I test the motherboards output with a multimeter just to make sure the new board is working ok?

 

[Nathan Willis]

Are you running an OS?
If your just in CMOS/BIOS the CPU may not be hot enough to enable the fan.

Most laptops will not use the fan to save power and reduce noise when the CPU is running cool.

If you have an OS installed run HWMonitor.

http/www.cpuid.com/softwares/hwmonitor.html

Tell us your temps.

That program does not work very well with AMD CPUs. (At least for me)

 

[AndrewHylands]

Are you running an OS?
If your just in CMOS/BIOS the CPU may not be hot enough to enable the fan.

Most laptops will not use the fan to save power and reduce noise when the CPU is running cool.

If you have an OS installed run HWMonitor.

http/www.cpuid.com/softwares/hwmonitor.html

Tell us your temps.

That program does not work very well with AMD CPUs. (At least for me)

Thanks Nathan, I'll try installing hwmonitor when I get home tonight see if it recognizes the fan. At present my testing is in windows 7, the BIOS does not have any fan settings to test it that way. It's an Intel i3 2310m processor rather than AMD.

I'll get you some temperatures tonight but I had CoreTemp running and I got a message saying core 1 was critical and the fan hadn't started so I turned it off before doing some damage.

 

[Nathan Willis]

Hook the fan up to a battery (9v) and see if it works.
The fan may be dead.

 

[AndrewHylands]

Hook the fan up to a battery (9v) and see if it works.
The fan may be dead.

Hi Nathan I installed HWMonitor and it doesn't seem to have found a fan either. I tried my old fan and new fan with a 9v battery and a snap on connector, the old one did not move but I think the new fan moved for a split second but can't be sure, it was very quick & didn't move again in future tries.

I think the fan is only 5v so the 9v battery might have fried it now but was worth a try to see if they moved. Might have to buy another but they are only about £5 currently. Core temperatures are at 75 degrees after 10 minutes and the fan has not started so I'm going to shut it down to let it cool. I have not put the keyboard back in place so I can watch the fan. Any ideas what I should I try next? Get a new fan and try to power it with something else or test the output on the motherboard some how? Possibly a multimeter?

Any advice would be good because I'm beat currently.

 

[Nathan Willis]

Yes, use a meter to see if there is any power to the fan header.
I assume you mean 75C? If so the is way too hot.
Get another fan and test it with the right voltage.

A DIY solution may be to get a new fan and connect the wires to the input power. (Jack)
You may have to use a resistor to make sure to voltage to the fan is right.

The fan is 3 wire for feedback, so make sure you connect the power to the + and - leads.
By hooking it up wrong you will fry it.

If there is not voltage at the fan header the MOB may be bad.

The only option after that is the DIY solution.