Toshiba Laptop Motherboard Fan cuts in and out

Thread Starter

stephanj

Joined Jun 20, 2014
7
Hi all, I will try and keep this short.

My Toshiba F60 Qosmio gaming laptop fan cuts in at max for 3 seconds then turns off for 5 seconds and this continuously repeats from start up, it does not slow down and speed up like it did before I took it apart to replace the thermal paste. 3 on and 5 off continuous from startup and this continues even if the laptop is on for 5 min or 20min.

The fan does not start on slow when you turn the laptop on like it used to.

The laptop got hot and I replaced the thermal paste on the gpu and cpu and reassembled the laptop and since then it is doing the above.

The cpu core temps are 50-60 degrees celcius at startup and slowly increases to 70 then 80 the longer you leave the laptop on but the fan does the same , on for 3 seconds at max and off for 5 seconds. This will also be the reason the cores heat up cause the fan does not run on slow neither does it run longer .

Any ideas appreciated. I looked and all the wires and ribon cables are plugged in. Maybe the fan controller got hurt ? Do I have a plug wrong way around . Motherboard circuit damaged when I took it apart?

Thanks
Sj
 

thedoc8

Joined Nov 28, 2012
148
It sounds like you have not got the cpu seated. The only way I could see 50 to 60 c on start up is the cpu not seated.
 

Thread Starter

stephanj

Joined Jun 20, 2014
7
It sounds like you have not got the cpu seated. The only way I could see 50 to 60 c on start up is the cpu not seated.
Thanks the cpu was not removed during the process and the fan will operate independently from the cpu, so at start up your fan should start regardless of temperature. It also should run and ramp up and down due to temperature fluctuations. This fan from the word go,/ start up, run for 3 secs on max then completely cuts out for 5 seconds only to start up at max for 3 seconds and cuts out for 5 and the cycle continues regardless of cpu temps.
 

danadak

Joined Mar 10, 2018
4,057
If heat sink not exactly flush on cpu or heat pipe misaligned with
spreader......thermal R dramatically affected.


Regards, Dana.
 

Thread Starter

stephanj

Joined Jun 20, 2014
7
If heat sink not exactly flush on cpu or heat pipe misaligned with
spreader......thermal R dramatically affected.


Regards, Dana.
Thanks Dana, it has me thinking , if I put too much thermal paste on it could also affect how the heat is relayed to the sensor. Mmm maybe I should re-open the machine and put less thermal paste on the cpu and gpu.

The other thing is that the gpu had a heatpad on and not paste. I replaced it with paste. I wonder if that could be it.
 

danadak

Joined Mar 10, 2018
4,057
"Heatpads not as effective as thermal paste", on web, so one would think.....

but then I found this -

You should replace thermal pads with new thermal pads or with a thermal pastethat is specially designed to replace thermal pads. Do not reuse old pads and donot replace pads with normal thermal paste like Arctic Silver. Both will lead to overheating and result to GPU or other BGA failure.Feb 14, 2011

Regards, Dana.
 

djsfantasi

Joined Apr 11, 2010
6,838
The other thing is that the gpu had a heatpad on and not paste. I replaced it with paste. I wonder if that could be it.
What is this “heatpad” you speak of? And what do you mean by “replaced it with paste”?

I expect that the cpu and cpu had
a heat sink attached, with a thin layer
of heat sink compound between. You implied that you’re just using heat sink compound alone as a heat sink.
 

Thread Starter

stephanj

Joined Jun 20, 2014
7
What is this “heatpad” you speak of? And what do you mean by “replaced it with paste”?

I expect that the cpu and cpu had
a heat sink attached, with a thin layer
of heat sink compound between. You implied that you’re just using heat sink compound alone as a heat sink.
Hi no there is a heat sink on both the gpu and cpu. The cpu had thermal paste but the gpu had what I would call a gel / rubbery thermal pad perfect square overhanging slightly.

First time I heard of thermal pads when I looked it up. In other words there was no cleaning needed of old thermal paste on gpu because the thermal pad just pulled off.
 

thedoc8

Joined Nov 28, 2012
148
Thanks the cpu was not removed during the process and the fan will operate independently from the cpu, so at start up your fan should start regardless of temperature. It also should run and ramp up and down due to temperature fluctuations. This fan from the word go,/ start up, run for 3 secs on max then completely cuts out for 5 seconds only to start up at max for 3 seconds and cuts out for 5 and the cycle continues regardless of cpu temps.[/QUOTE]
Thanks the cpu was not removed during the process and the fan will operate independently from the cpu, so at start up your fan should start regardless of temperature. It also should run and ramp up and down due to temperature fluctuations. This fan from the word go,/ start up, run for 3 secs on max then completely cuts out for 5 seconds only to start up at max for 3 seconds and cuts out for 5 and the cycle continues regardless of cpu temps.
You say you did not remove the cpu, so how did you replace the thermal past under it.

The laptop got hot and I replaced the thermal paste on the gpu and cpu and reassembled the laptop and since then it is doing the above.
 

Thread Starter

stephanj

Joined Jun 20, 2014
7
Thanks the cpu was not removed during the process and the fan will operate independently from the cpu, so at start up your fan should start regardless of temperature. It also should run and ramp up and down due to temperature fluctuations. This fan from the word go,/ start up, run for 3 secs on max then completely cuts out for 5 seconds only to start up at max for 3 seconds and cuts out for 5 and the cycle continues regardless of cpu temps.

You say you did not remove the cpu, so how did you replace the thermal past under it.

The laptop got hot and I replaced the thermal paste on the gpu and cpu and reassembled the laptop and since then it is doing the above.[/QUOTE]
Hi you do not have to remove a cpu to replace thermal paste, you remove the heat sink on top of it.

The problem has been fixed and it seemed to be a motherboard fan controller chip which they bypassed and set the fan to a medium constant speed which keep the cpu below 50 degrees C and max 55 degrees.
 
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