Acer Aspire U5-710 cooling fan crackling sound

Shturmovik
Shturmovik Member Posts: 5

Tinkerer

edited March 2023 in 2016 Archives

Hi there!

I've already written in my U5-710 disassembly guide post that the purpose of opening the chassis was to locate the strange sound which I doubted to be coming out of fan or the HDD. It was too strange. I was hoping that eventually the new BIOS firmware could eliminate this, but nope. =(

Here's the synopsis:

When you start the AIO, there's almost no noise at all. Then, after a few (10-15) minutes of work, when it heats up, it starts to make crackling noise every 1,5 seconds. The periods vary. There is no certain pattern. When it heats up more, the sound disappears and does not show up again until the temperature is low enough to stop the chassis fan. In this case it might come up again. But usually doesn't.

What it turned out to be:

By default BIOS is set to control the fans' RPM. Otherwise you get the "jet plane taking off" noise. And no crackling problems at all =))

I disassembled it, started from Live USB to eliminate the possible OS drivers effects, started AIDA64 stress test and watched the temperature rise. We have 2 fans on the back of the AIO. As you look at them the right one is recognized as CPU fan, the left one - is the chassis one. They are connected to separate connectors on the MB.

The CPU fan is rotating all the time gradually increasing its speed, but no discomfort, its noiseless while rotating at relatively slow speeds.

When CPU temperature exceeded somewhat around 53 the system decides to start the chassis fan and does this in very unusual way. As I see it:

  • BIOS gives power to the chassis fan;
  • it starts spinning, spins for 1 second;
  • BIOS stops giving power (considering, maybe, that at given temp this is enough);
  • the fan continues to spin inertially and while it hasn't yet stopped -
  • BIOS again gives power and here is where we get the awful sound.

After some time as the temp rises on and the chassis fan starts to spin uninterruptedly and then no disturbances at all. It's almost silent.

You can see at the charts attached the whole thing. The chassis fan start-stop issue is clearly seen at the screenshot, then it comes stable (the blue-grey line). Compare it to the temp chart (below).

The main stress-test section is 19:07 - 19:18.

1.jpg

2.jpg

This is the video of the whole thing with sound:

https://youtu.be/uDtQ9TMxB34

I believe this is totally a soft/firmware (BIOS) bug. The only thing we need to eliminate the sound is to correct the voltage/power amount to the chassis fan so that it does not stop once started spinning and continues at the slowest speed. Either way - not starting and stopping all the time until reaching some border where it starts to spin continually.

The other way of solving this problem may be by connecting parallelly the chassis fan to the CPU fan. As both are quite silent it won't be any trouble, but this will involve some light surgery to the AIO PC.

I now address the ACER engineers - please tell if it is possible to solve the issue (which seems not so hard to eliminate) with BIOS upgrade only?

If so, please fix the bug in the next BIOS firmware upgrade which is totally necessary now.

Otherwise please tell me any way to solve the issue, as it annoys me seriously.

 

Anyone, any thoughts? Does someone have anything like it?

 

Answers

  • laurent_14
    laurent_14 ACE Posts: 10,354 Trailblazer

    Hello,

     

    I understood your issue but there is a weird thing. If you compare both curves, the temperatures of the system and cpu don't "reflect" the fan system speed (between the red lines):

     

    AC-Both curves

     

    My first thing was the temperature hysteresis (E.g. +/- 2C). That would mean the starts and stops of the fan.

    Have you tried disabling the smart fan option (full speed) in the bios setup utility?

    Do you know SpeedFan? I often use as a diagnostic tool about the fan issues.

    France
  • Shturmovik
    Shturmovik Member Posts: 5

    Tinkerer

    Hi!

    I think, in fact there is a correlation between temps and fan speeds. Maybe not so obvious. But the system turns on the chassis fan only when temp rises up.

    Yes, like I said, this all occurs when the "smart fan" (or how it is called) option in BIOS Setup is enabled. Otherwise both fans work at max speeds which is a small tornado and a very loud one.

    The SPEEDFAN utility is now rather old and does not see any of the fans. I've tryed it.

    I will try to do a more detailed test to find any dependencies of fan speed on the temperature.

     

    But still seems quite clear to me that there is something in the chassis fan control algorythm when it is intended to work at slowest speed possible.

  • lucasschoch
    lucasschoch Member Posts: 1 New User

    Hi!

     

    I have the excact same problem with my new aspire U5-710. Is there a solution by now?

     

  • Shturmovik
    Shturmovik Member Posts: 5

    Tinkerer

    In fact Acer ignores the problem. I have contacted support to request BIOS update that can fix the problem but they've only replied that the issue is passed on to the tech desk and kept silent up to date.
    I believe we both should write (and not only once) to the support. The more we write the sooner they'll notice the problem.
    Please inform if you find anything.
  • HDR
    HDR Member Posts: 1 New User
    Hi,

    Is there a solution for this problem? Mine does it also. New straight out of the box.

    Can the fans be replaced? Could replacing the fans help?

    Thx for the response!