HOW TO REPAIR LAPTOP CPU FAN CIRCUIT
Laptop CPU Fan Not Working Properly | Laptop CPU Fan Making Noise | Laptop Cpu Fan Replacement | Laptop CPU Fan Diagnose
If you have a working fan and it is properly connected with laptop motherboard and by bad luck it’s not spinning as usual.
First of all try to update laptop BIOS and if still nothing fixed then come down to CHIP LEVEL treatment of laptop. Now only two thing you can do to make laptop again working.
1. Check +voltage and senser track from fan connector, find out the CPU fan PWM controller circuit, cpu fan supply comes from output section of fan PWM circuit and this circuit not a smmiliar kind for all laptops and notebooks basically +5 voltage required on Vcc pin to spinning fan and to find out Vcc pin of CPU fan read my previous post no CPU COOLING FAN NOT WORKING
check cpu fan controller circuit and it’s all fusible resistor or small coil in circuit with a simple OME meter or continuity meter coil and fuse should be show zero continuity on there surface and if no continuity , found open component then you can bypass them using a unshielded Cooper wire.sure it will work again if other things are OK
and unfortunately no any coil and fuse you found on fan controller section then just resold this section using hot air-gun and check other components of fan PWM circuit if possible at your own way
2.now you try all you best and still have same problem then now a good news for you because we can power up laptop notebook cpu fan Directly without using PWM controller circuit..
just found out the +5v track on motherboard nearby fan supply track ,connect the fan Vcc pin with +5v track using shielded thin wire jumper on motherboard and some time you can make your fan alive as just remove only the sence pin of fan from it’s connector if + five volt is already coming on the power pin of fan.
now your fan will start working but it will start spinning in a same speed non stop till the laptop is on. but doing this thing please confirm that which supply given to fan directly by jumper that will be generated after you turned on laptop.