Does anyone know why my fan would be on a lot after replacing my keyboard?

[Redheadguy10]

I recently added a new keyboard to my Probook 450 G5. As I had it open and was fitting the thin wire connection from the new keyboard the machine came on and the fan started. I held the on/off button down for 20 seconds and it turned off. I installed the new keyboard and noticed the On/Off button being lower than before. The fan now comes on a lot - it didn't before and it's almost a constant, even when the CPU usage is low.  Does anyone know if I can make a software adjustment to regulate that please?

Probook 450 G5

Windows 11

And I'm a complete idiot with computers so please speak with me as you would a child of 5 ! 🙂

[TzortzisG]

Hello Redheadguy10!

I seriously doubt that you're a complete idiot with computers if you managed to change your keyboard. However, I'm afraid you didn't carefully read your manual before attempting this repair. If you read your manual now, you will notice two things. 1) It warns you about taking special care to avoid electrostatic discharge while "messing" with internal components and 2) All power to the system has to be removed. The AC adapter has to be unplugged, and since the battery is difficult to remove on this system, there's a special setting called "Battery Safe Mode" you have to turn on!

Since, apparently, you didn't enable this setting before "gutting" your laptop, all components were being powered by the internal battery at all times (meaning voltage was still applied to your motherboard). You're not allowed to hot-plug motherboard components, and powering on surely didn't help any. I'm guessing that a short-circuit was caused somewhere on your mobo, probably one of the thermal sensors since the fan is now constantly running. I would count myself lucky that this system is still booting and in otherwise operable condition........

[Redheadguy10]

Thanking you kindly for your thoughts. This was a second hand laptop without a manual. I did look on YouTube and I followed the instructions given on this video. https://www.youtube.com/watch?v=SU7gKF4DHgo 

Thanks for your technical answer about the components and the possibilities.

Apparently, I'm somehow able to turn down the internal heat register somewhere which I suppose kicks off the fan. The fan comes on even if I open my browser.

Any thoughts on a 'work around' which tells the fan 'it's not as hot as you think it is'??

Many thanks indeed...

[TzortzisG]

No problem. The only workaround I know of is to take control over your fan (read this post and its links https://h30434.www3.hp.com/t5/Notebook-Hardware-and-Upgrade-Questions/Z-Book-15-G2-Fan-runs-constant...). Not an easy task to accomplish, I have to warn you. But first use HWiNFO to take a look at the temperatures and see if there is any other kind of problem. The link to the program is included in the above post. You need to activate the sensors.

[Redheadguy10]

Thanking you kindly for the link. I think 'messing around' more with this is beyond me. By the way, when I did open up the back to undo the screws on the old keyboard, the 3 x screws to secure the keyboard weren't there! .... so the keyboard had been replaced previously.