CPU fan keep high speed

[jay_dunne_jie]

Intel D925XCV motherboard, MPC ClientPro 565. very old desktop. After a failed bios update, the CUP fan keep high speed at all conditions. Even after Bios was updated successfully, system (Windows 7 SP1) works well. The fan is still roaring all the time. Before, the fan roared only at startup for a very short time and be quiet (lower speed) right at the logo page shows up, then auto adjust speed according to CPU temp. During the failed bio update, by mistake, set the jumper to front chassis fan connector with power on. Please help to fix it. Thanks. 

[pressed_for_time]

This motherboard should have a 4 pin PWM CPU fan connector. Since the pin-out graphic below.

The blue wire carries the PWM signal which is a duty cycle percentage. The duty cycle percentage increases as the CPU gets hotter. So what you observed as the fan running at high speed to start with and then settling down to a lower speed is normal for a PWM Intel CPU cooler fan. It is a thermally controlled fan, the initial burst of speed is to clear dust.

The alternative to PWM fans is 3 pin fans (no PWM wire) and the chassis fan headers on this board will be 3 pin only. So if you plugged this PWM fan into a 3 pin chassis header it would run in 3 pin fan mode. This would make the PWM fan run at full speed all the time which ties in with what you are seeing. But putting the PWM fan back on the CPU 4 pin header should mean that it will then run as normal at a much lower speed.

So what you need to check is that the CPU fan is plugged into the CPU fan header correctly. That there is nothing in the BIOS setting the CPU fan header to 3 pin mode. That there is no jumper on the motherboard setting it to 3 pin mode. And then it should run as intended.

[jay_dunne_jie]

Thanks a lot for your response and instructions. Very helpful! Yes there is no fan control setting in the bios. The CPU fan is plugged in a 4 pin header. The accident happened by plug bios jumper block to the nearby front board an open chassis pan connector with 3 pins by mistake. After recovered bios and suppose to put jumper to 2 3 position but accidentally put to fan header, then powered on and fan started roaring since then, notice the mistake and removed the jumper block even with power on. I thought it did damage the board somehow overwrite the PWM. The fan now runs full speed all the time. Later successful update bios wont fix it. Now win 7 runs well, CPU works fine, but when restart system always give one beep indicating cpu error  and fan runs full speed. 

[n_scott_pearson]

This mobo supports a 4-wire header for PWM control of the processor fan and 3-wire headers for voltage control of the chassis fans. There's no jumpers or configuration parameters that affect this. You can plug a 3-wire fan onto the 4-wire processor fan header, but it will run at full speed constantly.

The Heceta ASIC that controls the various fans will drive the fans at 100% by default, so the fans coming on and staying on is an indicator that the BIOS did not program the Heceta ASIC properly. This could be a fault or it could be an indication of a lack of fan speed control configuration within the BIOS.

• I have seen this occur as a result of the onboard CMOS battery running out of power. For the very small amount of money involved, I would suggest replacing the CR2032 battery before anything else. After replacing it (with power off), power on and use the F2 key to enter BIOS Setup. I would then recommend that, after setting the date and time, you use the F9 key to reset the BIOS configuration and the F10 key to save this default configuration and reset the system. If, on the resulting BIOS POST, you hear the fan slow down, you know the process was successful. You can then go into BIOS Setup again and make any configuration changes that are needed/desired for your system configuration.
• I have seen this occur because of a fault occurring on the board's SM Bus. If the bus is not operating properly, the BIOS will be unable to program the Heceta ASIC. In this case, a possible cause of this is a bad or improperly install PCI/PCIe card. I would suggest testing with a monitor plugged into the board's VGA connector and remove any PCI/PCIe cards installed including any graphics card.

Those are the two most-common cases. Hopefully one of these resolves the issue.

I have attached the documents that I have for this board in my archive. I have also attached the final BIOS release. I suggest that you install it using the jumper-based BIOS Recovery process.

Hope this all helps,

...S

[jay_dunne_jie]

n_scott_pearson

Thank you for the detailed analysis and good suggestions. Will follow suggestion to change the battery first and unplug graphic card. I have not any PCIe card plugged in the board.

Also, thanks for the documents. I tried windows and jumper recover by CDROM of this 0504 final version of bio, it won't compliant. Now my bios updated to the second last version 0477. Not big differences from 0354 it had before.  I put the details when the accident happened in upper post reply, would you please review it and give some further diagnose of the issue and further suggestions? Again, many thanks. 

[jay_dunne_jie]

Tried both suggestions by replacing new battery and remove graphics card. The fan issue is still there. I will try to flash the bios again to 0545 and see whether that helps. Thanks any way. 

[n_scott_pearson]

Remember, do it using the jumper-based BIOS Recovery process. This ensures nothing is left behind.

...S

[jay_dunne_jie]

Will do and will let you know the results. Thanks!