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Aluminum Metal Heatsink Raspberry Pi 4 Case with Dual Fans n
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Aluminum Metal Heatsink Raspberry Pi 4 Case with Dual Fans n

by luisnaranjo733 on Fri Oct 22, 2021 11:55 pm

I purchased the Aluminum Metal Heatsink Raspberry Pi 4 Case with Dual Fans (https://www.adafruit.com/product/4340)
The fans are connected to url

Sometimes one fan or both fans randomly get really loud. I have to move the RPi sometimes in weird ways to get it to stop. If I tighten the screws it gets really loud. Sometimes loosing the screws helps. What has slowly happened is that the screws ended up getting completely loose out of neccessity.

This doesn't feel right - are there any suggestions for how far to tighten the screws to make the fans less loud? It sounds like the blades are chafing against something. Almost as if there were chopping at a cable under the fan hidden from view.

Would appreciate any advice.
Thanks!

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Re: Aluminum Metal Heatsink Raspberry Pi 4 Case with Dual Fa

by mikeysklar on Mon Oct 25, 2021 8:59 pm

Interesting observation torx tension can help reduce the fan noise. Maybe run them loose with some threadlock to prevent them from slipping? These fans do generate a fair amount of noise.

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Re: Aluminum Metal Heatsink Raspberry Pi 4 Case with Dual Fa

by gmcmullen on Mon Nov 15, 2021 5:48 pm

Wanted to follow up on this, as I think there are a fair number of customers who have experienced the same issues with the fans on this heat sink. The fans are rather small with a very thin plastic frame and extremely tight clearance between the fan and the frame. I suspect that either the frame gets a little warped over time / with heat, or even enough dust accumulates inside the frame.

I should note that the product page doesn't specify that the fans are quiet. The video presentation does mention that they seem quiet, but I take that as a not a specification, but rather a general remark. In fact, the product page recommends the fan-less version if you're looking for something quiet.

I'm personally doing a bit of experimentation, including compiling, on my Pi4, so the fan was generally necessary for me. Unfortunately, Adafruit does not sell replacement fans for the case. The closest item they have is a 30mm square fan, which is too large. The fans on this heat sink are 25mm square by 7mm thick. Luckily Amazon and other shops have a large variety of these fans available. Other specs may matter to you as well. The power specs on these fans are 5V / 0.15A each. Also, I had to make my own cable to connect both the fans at the same time as they are on the original case.

In general I've found fans this size run at about 10k RPM with 25dBA noise.

Hope this info helps.

- George

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Re: Aluminum Metal Heatsink Raspberry Pi 4 Case with Dual Fa

by mikeysklar on Tue Nov 16, 2021 3:19 pm

George,

Thank you for the thoughtful summary.

What dBa do you feel you started at and what have you brought it down to?

When I look at a chart describing fan noise in general devices 25 dBa is on the level of a whisper or wall clock ticking measured at a distance of 3 meters.

Screen Shot 2021-11-16 at 11.17.39 AM.png
Screen Shot 2021-11-16 at 11.17.39 AM.png (287.88 KiB) Viewed 147 times


https://ventilation-system.com/sound-features-of-fans

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