My computer is making a lot of noise.

A little trick that might be a bit tricky but has worked for me for years.

Unplug the fan or fans. Many of them have a small adhesive dot at the center of the blade.
I carefully peel off the dot and put a tiny drop of a lubricating oil, like Vaseline, on the shaft of the blade.
Make sure to wipe it off afterward and put the adhesive dot back on, then plug everything back in.

No more noise!

Repeat once or twice a year.

Bonjour, s'il vous plaît, j'ai un HP Pavilion dv6500 et après un an depuis l'achat, il fait du bruit. Je ne l'ai jamais ouvert pour entretenir les ventilateurs, je ne savais même pas qu'il fallait le faire. Pourriez-vous expliquer davantage sur le système de refroidissement et les radiateurs ? Dans quel magasin puis-je les acheter, et concernant le nettoyage à l'air sec, s'il vous plaît ?

MEASUREMENT OF ANEMOMETRIC



An anemometric measurement showed that the fan of the noisiest central unit mainly blows air from the front at speeds of around 1.2 m/s compared to 0.2 m/s on the left and right sides. The flow instabilities caused by the various obstacles, including the front grille of the fan, generate vortices responsible for the broad band whooshing noise perceived by people in the adjacent rooms.


A high level of 75 dBa is observed primarily in the frequency bands corresponding to voice frequencies: 1000 Hz, 2000 Hz.


Origin of the noise


The noise from the fans has two distinct causes, classified into:

-aerodynamic noise

-mechanical and electromagnetic noise


The aerodynamic noise, associated with the interaction of the flow with the blades and the fixed parts of the fan, is the primary concern as it is predominant in the vast majority of cases.

Electromagnetic noise refers to the noise from the electric motor driving the fan. Motors are generally of the induction type, single-phase for low powers, and three-phase for powers exceeding a few hundred watts. The motor noise itself has several sources: it can be due to the cooling fan of the central unit. Standard microprocessors are designed to operate at around 40 degrees under standard usage and around 45 degrees when the server is tasked with "resource-intensive" applications. The cooling of the microprocessor, controlled by the CPU, increases the fan speed to avoid exceeding 65 degrees (the temperature limit for electronic components...). These forces cause vibrations in the motor structure, which then emit noise either through airborne pathways or through solid pathways via vibrations of the central unit casing.

Context



Here, the fan is located in a cramped room that somewhat acts as a resonance chamber: the reflective wall coverings will contribute to creating a reverberant field that adds to the direct field produced by the fan.



A quick numerical modeling (see graph on the next page) showed that the enclosure of the fan amplifies the resonance chamber effect in the room. In this modeling, two treatments were considered:

* The installation of an absorbing coating such as foam + heavy mass significantly reduces the reverberant noise (Figure 2).
* The installation of an acoustic cover, which attenuates noise at the source, improves the reduction of direct transmissions.



Two complementary solutions should therefore be considered:

* There is a need to isolate the fan from the rest of the environment by installing an insulating cover that will absorb part of the direct field in the room and will also ensure soundproofing of the adjacent offices. The result of the modeling shows that after adding the cover, a reduction of 10 dB is achieved in the main office.

* We will also seek to reduce the reverberant noise by installing a mineral wool + heavy mass coating on the walls of the room.