Solved: Fan will not go to full speed on ProBook 4720s - HP Support Community

fanerror · ‎05-15-2012

I have a ProBook 4720s laptop, Windows 7 64-bit

The problem is that the fan on my computer always stays at minimum speed and as the computer heats up, the fan will not speed up to its full speed. The computer gets really hot ~70°C. The problem occurred when I upgraded bios to its latest version F.20. I believe that there is a bug with this bios- that the bios will not control the fan properly. This type of notebook has a history of bios bugs: its original bios made the fan run all the time at full speed which was fixed with a bios upgrade.

This bios came with a note that I cannot downgrade to a previous version that worked well. So my question is, can I expect a bios upgrade for this computer that would fix the error.

fanerror · ‎08-25-2012

to: erhart-jir

there is a temporary workaround. do it only at YOUR OWN RISK.

this procedure only works on ProBook 4720s F.20 bios. DO NOT ATTEMPT THIS METHOD ON OTHER MODELS!!!

it works only when the laptop is on AC POWER. download "read and write utility" from http://rweverything.phpnet.us/. run the program then click the EC icon (embedded controller). in the embedded controller window that opens you will see a matrix of 16x16=256 numbers choose the one in column marked "05" and row "D0". that number has an offset address of 213(in dec) and probably a value of 1E.

(if you didn't find it don't attempt to change a random number, its risky)

change the value to something from 0 to 70 (don't go over 7F) and the fan will speed up to the desired value.

also do not change any other values - risk of hardware damage

the procedure must be repeated on every startup

this procedure only works on ProBook 4720s F.20 bios. on other models the offset is different so do not attempt this method !!!

do it at your own risk only

the core of the problem probably lies in the bad DSDT table (that came with the bios), but i guess you would need an expert to fix it.

if you need more help you can leave a post

View solution in original post

erico · ‎05-15-2012

Have you gone into the UEFI environment -->Advanced system diagnostics --> BIOS management to verify that is indeed the case?

When you updated the BIOS did you use the UEFI BIOS method?

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fanerror · ‎05-15-2012

i have gone into >Advanced system diagnostics --> BIOS management there are two options "update bios" and "revert bios" (both are currently empty saying there is no bios to be updated). i'm not sure how to verify that faulty bios is indeed the case (my assumption is based on lack of other possibilities)

when i updated the bios i did it directly from windows(i don't know if that's uefi method). a also flashed it twice to eliminate random errors but it didnt help.

best regards

erico · ‎05-16-2012

Which CPU does your notebook have?

Whaich utility are you using to get your temperatures? CoreTemp?

From the specs that I found it shows your notebook has the Intel Core i3 - i5 M series.

Tj is 105 degrees C. If what you are seeing is 70 deg C, then it is still nothing to worry about.

I will ask internally about the thermal ramp issue for the fan on this version of the BIOS.

I am a volunteer forum member. If my suggestion helped you solve your issue, help others by marking that post as the accepted solution. Say thanks by clicking on the Yes button next to the "was this reply helpful?"

fanerror · ‎05-16-2012

i have a Intel Core i5-430M with

ATI Mobility Radeon HD 4350 Series

for reading temperatures i used hwinfo32

the graphics processor also gets pretty hot (usually hotter than cpu). I agree that 70°C is still safe, but i believe it gets even hotter (i did not measure temperature at its peek).

i remember previous bios turning on the fan at ~60°C (when i used some more demanding programs it turned on immediately), but now it stays at minimum at all times and i am unable to run anything more demanding. when its not on AC power the fan is completely turned off

perhaps if there was a fan control program that worked with that model or if i could somehow revert to previous bios version(this bios says i cant) that would solve my problem.

also thank you for replying and helping

wes_notebooks · ‎05-18-2012

It may be unrelated but have you tried updating or removing the HP Power Assistant?

ftp://ftp.hp.com/pub/softpaq/sp54501-55000/sp54635.exe

It appears to be a common issue for this platform. Other than that I don't see any known issues similar to your symptoms.

-wes

I am an HP employee.

fanerror · ‎05-19-2012

thank you for replying

i have removed hp power assistant some time ago and I didnt notice any change.

Is this issue specific only for my computer? perhaps if you could inform me at which temperature do other probook 4720s computers turn their fans to full speed i would know for sure if i even have an issue (only computers with f.20 bios, - on previous bios fan starts at 60°C). maybe the notebook turns its fan on at 95°C (i think i never went past that temperature)

fanerror · ‎05-28-2012

I am still very interested if anybody knows at which temperature the ProBook 4720s with F.20 Bios version would turn on the fan at full speed.

Any information will be greatly appreciated.

adv74 · ‎06-21-2012

I have the same problem.

erhart-jiri · ‎08-25-2012

I want to report this same problem too, after UEFI BIOS update to 68ZAA Ver. F.20 the fan keeps rotating at minimum speed even when the CPU temperature reaches 100°C. I'm quite sure it's a BIOS problem, because it doesn´t matter which operating system I use and the issue remains even while running the advance diagnostics tests in the UEFI BIOS menu.

I find this quite critical. The laptop isn´t useable for me anymore since I can´t run even Inscape or similar programs. Would there be any chance of downgrading this version of BIOS? Or is HP planning to release bug free version of UEFI BIOS for this computer (ProBook 4720s) soon?

I have spend two days already searching for some solution, nothing helped. I have tried to downgrade the BIOS, but without results. Also programs like SpeedFan don´t work for me, they don´t even find the CPU fan.

Any help would be truly appreciated. I thank you in advance.

Fan will not go to full speed on ProBook 4720s

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