We recently shut down our server to replace the batteries on its UPS. Normally, the fan runs on high when it is first booted up and then returns to low (or off) and is essentially noiseless. Since we replaced the UPS batteries, the fan stays on continuously and is quite noisy. I shut it down and plugged the computer into the wall outlet with the same results so I think I can disqualify the UPS as a problem, i.e., in the event it was getting inadequate power. I'm trying to figure out how the fan is controlled with the idea that perhaps something was reset during the battery replacement. However, I don't have a clue. Any ideas? Assistance is much appreciated.

Can you give us the make and model?

Has the Battery fully charged yet? as it could stay on till it's fully charged?

The batteries are fully charged and the problem remains. I'm not at my office but I believe the UPS is an APC XS1500 with a good display of charge and load status. The motherboard is a generic one that our server provider bought online five years ago.

I might have misread your post.

You said you plugged the machine direct to the Power on the wall and it's the machine that's making the fan noise?

Any sign's of dust ? and did you check the machine to make sure nothing came loose inside?

If it's the UPS, you can have it's fan on while it charges or trickle charging. How long ago did you replace the battery?

Was just reading somewhere that, you may need ot check the Battery for any cracks if it's just the UPS which has the issue, please report back.

I tried cleaning the dust out with compressed air after I first started seeing the problem. Didn't help. I didn't observe anything loose inside. The fan is on the computer, not the UPS. My mention of plugging the computer directly into the wall was just to emphasize that it doesn't appear to be a UPS problem which is what I suspected at the beginning when it went dead.

Check your CPU usage and see whether it is very high or low. Tell us the percentage for all the CPU usage.

CPU Usage varies from 0-15% but the median usage is probably 2-3%. Fan remains on during this time.

Can you boot into safe mode and see if the fan is still is running high?

Wondering if you have some service running which is stuck like Windows Update.

Boot into the BIOS, and check your hardware configurations. You may find that the fan is set on high. I've seen BIOS settings reset for no reason at all, and a power flux can definitely do it. Also, is the server running normally?

I went into Safe Mode but fan continued to stay on. I got into the BIOS console but I didn't see a place for setting fan speeds. Usage continues to be almost negligible but fan stays on. ??

Just to make sure, which fan is spinning, CPU or case fan?

Please tell us you make and model of the Machine, as the Power Management section in the BIOS, should be where the fan settings are. If you are techinical, you could try doing BIOS default's but make a note fo what settings are their first.

I'm away from my office but I finally found the fan options before I left. I had the choice between acoustic and, I believe, high performance. Neither made any difference to the fan. It stayed on high.

Is it a case fan or CPU?

If case fan, there should be more than one connector on the motherboard for it, or you can get a converter for a 4pin molex to check it.

I'm not really sure. The airflow is out the back of the unit but inside it has a large plastic cowling with a 90 degree turn that directs the air right onto the motherboard and, I believe, on the processor.

What temp does the CPU show in the BIOS?

I won't be back in my office until Sunday but I don't recall seeing a temperature indicator in the BIOS. Is that pretty standard or is there some kind of application I need to load?

It's in the BIOS under the Power controls I think, also you may have motherboard utilites, but could get Speedfan


Allows you to adjust the fan speeds also.

The only indications that apply to the fan in the BIOS are for acoustic and performance. I've tried both without success. I don't see a temperature monitor at all. I installed Speedfan but there doesn't seem to be anything out of the ordinary. The fan that is on and so noisy is the one that cools the motherboard. It has a heavy-duty plastic cowling around it.

Any chance of taking photo's?

Sure, what would you like to see?

The fan's inside and is it only one fan being noisey?

Are you saying to get a picture of the fan? It is the only one being noisy. Actually, it is not so much that it's noisy but it is usually only on high speed when the computer is first booted and then goes back to either off or quiet speed. Since this began (when we first took it off the UPS to replace the battery) it has been on full speed constantly. How do you attach pictures in here?

I'd like to post some pictures of the fan but I don't know how to post them. Advice?

When you taken photos of the fan, just go and post. When you post, click on Use Advanced Editor beside teh Post Reply to this Thread. After that you will see a paperclip sign, that is for attaching photos.

My photos are too big to upload so I Winzipped them. Less than the 10MB limit but for some reason the upload failed. I may just have to take the computer to a shop.


Before you do that, can you make a note of all your BIOS settings and do a BIOS defaults.

Also you may want to check is there is a BIOS update.

Any particular settings to note? How do I do a BIOS update?

Need to check the make and model of the motherboard, and then we can help locate it.

You should note as much of the BIOS as you can, Memory settings, CPU etc.

It's to make sure, if after you do a BIOS default, you have not lost some setting's like serial port, audio setting's and the one's I mentioned above.

BIOS updates help to make sure you BIOS hasn't got any issues.

Try, unplug the power cord and remove the battery, holding down the power button over 20 seconds do not let go.
This will discharge and reset the computer,

reseat the power connectors.

hope this helps.
Tech manager