Acer Aspire 9420 and sensors

[i92guboj]

Hi.

I have been struggling to get this working for a few weeks, so I thought it's about time to try to get some help

I have one of those laptops. It works fine but lately it has started to make some strange noise on the right fan. It happens like 2 or 3 minutes after powering it on. It lasts like 30 seconds, then it goes quiet again, and it usually stays quiet until I turn it off again, even with high cpu loads.

The cpu temperature is fine, so I am not worried in that sense. But I'd like to see how the fans spin up or down before trying surgery on this thing. My main concern is that the fan engine might burn if the fan is either locked or loose.

Now, the bit I need help with is that I an unable to get any lecture from the fans. Gkrellm can't find any, and lm_sensors only reports this:

[Roman_Gruber]

AFAIK a notebook should be cleaned every six months. if its a cheaper model or brand it is necessary more often. cheaper brands also sometimes ship half defective fans also. Personally (sorry) i think acer is such a brand.

my usual solution is to fire up a very new livecd and check if the sensors are there and if you can read them out there.

as these days there is udev/ eudev / systemd taking over and for myself it is not clear in which direction the paths goes. Therefore I want to point out, in the old days it was much easier to see how and where to read out the build in sensors.

some boards are not able to read out the sensors anyway.

summary, get a very new livecd with newest kernel and userspace tools and try it that way. or build the newest kernel with every module build in and check, but i can not guarnatee the success.

[i92guboj]

[Roman_Gruber]

[i92guboj]

[destroyedlolo]

[Ant P.]

The usual answer here is to boot with acpi_enforce_resources=lax - it might make your fan sensors accessible but even that doesn't always work. For ACPI, especially on notebooks, brokenness is the norm.

[Navar]

Without hearing the noise, my guess from your description would be it's a sleeve based bearing fan. Startup noise is generally due to friction drag on the bearing and motor versus the amount of power being applied (and in this case, probably having trouble getting going). You could try a very lightweight oil, particularly sewing machine oil, just a tiny amount once you've exposed the semi-sealed bearing area (remove tape, plug, etc. on back of fan). But as you probably know, especially since it's Acer, it's most likely sleeve bearing and eventually junk. The alternative being bearing based, which can work under high load and rpm for a long time, but can produce significant high frequency running whine noise over time.

Ideally, see if you can source a replacement. There is the possibility of burning out the fan header supplying the power due to the fan failing.

Oh and contrary to some of the advice, big kernel changes a few years back (from 2.6 days) caused grief for older sensor readings and why lm sensors will flat out fail at times (if this is older hardware). What Ant said applies in a workaround to help deal with the matter, but you may well want to try an older distro release livecd for testing (circa 2008-10 should work), rather than anything new. I've got an A7M266 mainboard that has been a pain for this.

[i92guboj]

[i92guboj]

So, no trace of the sensors.

I found -finally- a second hand replacement for my fan on a local store, and the noise has gone. For now.

A big "thank you" to everyone who contributed to the thread.