UX31A2 rev 4.1 fan always on

[jasko_jacker]

Another ux31 with a fan issue, but this time I could not solve with a clear ME.
The strange is:
with no lcd cable connected
FAN_PWM and FAN0_TACH change value
the fan speed goes from 0 to 50% of the maximum
with lcd connected
FAN_PWM and FAN0_TACH don't change value
the fan speed remain at max speed

This for me exclude a ITE problem , but what connection there is with the screen ?

[caspian]

Re: UX31A2 rev 4.1 fan always on

does it boot or display anything on the screen?

[cacla]

Re: UX31A2 rev 4.1 fan always on

here is dump and schematic

[jasko_jacker]

Re: UX31A2 rev 4.1 fan always on

does it boot or display anything on the screen?

Yes boot, all works fine , temp are very low (cpu < 33 c°) but fan always at max speed.

The tool to control the fan speed recognize fan rpm but it not be able to change the fan speed .

[jasko_jacker]

Re: UX31A2 rev 4.1 fan always on

could I read the signals from the cpu to the ec (smb1 protocol) but changing the hex values in the ec via r / w everything or through fan control the fan should change speed even if the ec does not receive the correct signals from the cpu?

[ado1]

Re: UX31A2 rev 4.1 fan always on

Hi, Have you resolved the issue. I am having the same problem. After replacing the MB ux31a2 from rev2.0 to 4.1 everything seems to be working besides the fan. It is always on and I tried every driver and every setting in bios. Can anyone help?

[atsio]

Re: UX31A2 rev 4.1 fan always on

SMB1_CLK and SMB1_DAT signals also come from lvds connector. Probably problem with those signals from lcd screen. Try to replace screen. What if you disconnect those two signals from lvds connector (remove the two resistors, r4505 and r4507);

[ado1]

Re: UX31A2 rev 4.1 fan always on

Thanks for replying back. I did find out that it is the LCD screen and when I unplug it I was able to hear the sound when it loaded into windows.
What are my options now, under no circumstances do I want to replace the screen and it is a similar looking computer to mac book pro. So are you suggesting that I physically remove those 2 resistors from the board because there aren't any loosely looking wires or leads to resistors and we are talking about resistors soldered on the board?

[atsio]

Re: UX31A2 rev 4.1 fan always on

Yes, desolder them, if they are placed on the board. If then didn't place them (there must be a position on the board) you have to cut the line on the board at those positions. The other think is, I notice on the schematic that the data line goes and to the light sensor pin on ITE coming from the lcd. Did you do anything to the light sensor?

[ado1]

Re: UX31A2 rev 4.1 fan always on

I didn't do anything yet and I am not sure if I want to. I am just trying to upgrade my computer from 4GB to 8GB of RAM and now I have to deal with all of this. I thought that same model board, fitting in one should be sufficient. I didn't cut the fuse or the line nor have I done anything to the light sensor. I have the original board that was in the laptop and it works fine. I see Jasko talk about clearning ME here, what would that do?
And by the way if anyone else comes across this post to look for a solution I want to let them know that I tried the FAN Control Software and it doesn't work. It wouldn't recognize the sensor so it was to no avail.
I would really appreciate if there was any alternative to removing the transistors.

[jasko_jacker]

Re: UX31A2 rev 4.1 fan always on

For my problem I'm waiting to replace a ITE

[caspian]

Re: UX31A2 rev 4.1 fan always on

Before attempting any repair, I recommend testing with another screen and another video cable. There is a bit of chance that this solves the issue. Sometimes, the solution does not make sense.

[ado1]

Re: UX31A2 rev 4.1 fan always on

I don't have another screen laying around and they don't come cheap. It would be nice if I could fix this without having to waste more time and money. As much as I enjoy working on this stuff and I wasted hundreds hours on this mambo-jambo, so an alternative with the stuff I have would be epic!! I might just sell it as is, but a fix would be great.
I agree: sometimes a solution does not make sense. Please let me know if, anyone else has a good approach to this mambo-jambo.

[caspian]

Re: UX31A2 rev 4.1 fan always on

Dear ado1: how does the fan behave while the screen is disconnected ?

Dear ado1 and jasko_jacker: how does the fan behave while the screen is disconnected and an external monitor is connected? does it display anything on external monitor ?

[jasko_jacker]

Re: UX31A2 rev 4.1 fan always on

In my case the external display works well (internal lcd flat disconnected) the fan speed change but not with correct speed / cpu temp.
And The fan speed tool now can change the speed. I try with another lcd with the some result. Unfortunately it''s not simple open the lcd case because the frame is firmly in place with strong adhesive .
I have 4 of this model in repairl 3 of ux31e with 4G repaired and works well and one of ux31a2 wit 8g with this fan ssue. Drbios and vina fix teach are sure there is an me problem but in my case I don't think

[jasko_jacker]

Re: UX31A2 rev 4.1 fan always on

This is the tool and the ME bin file to perform a clear me.
1 - use bootable dos pen and FPT tool to make a dump of your bios
2 - run ME_Injector as administrator
3 - choose the directory where there is the file me 8.0.10.1464_1.5MB_PRD_RGN.bin
4 - load your bios dump
5 - If in "Suitable MEs" not appear the me file chose Update DB
6 - If no errors use "Save new Bios" to save a clear ME new bios
7 - Use FPT to programm the new bios

I attach a UX31A2 clear me that I make for my laptop

[ado1]

Re: UX31A2 rev 4.1 fan always on

Jasko - has this worked for you and are you having any issues now ?
Thank you for the file.
Caspain - after disconnecting the LCD I was able to boot to windows. I didn't see anything, but I heard Windows play welcome sound when it got to the login. It booted quietly without the fan running. I assume it would kick in proper time when cpu's temperature moved higher .

[caspian]

Re: UX31A2 rev 4.1 fan always on

Dear ado1 and jasko_jacker: It seems some Asus laptops used to keep the fan running at a low speed even when the CPU is really cool.

Dear ado1: It is very important to test the fan behavior and display using an external monitor while the screen is disconnected.