I’ve done some modifications to the cooling setup of the EON, which makes fan noise fairly acceptable imho.
- I’ve swapped the fan with a Sunon MF60101V3-1000U-A99
This has lower RPM (@12V) as the original fan. Since its mounting holes are only 4mm, it sits on top of the fan mounting studs - that does not yet cause problems with 3 1/2" drives. - To increase air flow through the enclosure, I’ve made a simple air guide, which makes sure the fan exaust air actually is routed out of the EON:
The fan sits in a cutout of the ABS sheet, which is fixed to the top cover by scotch tape. - The fan control itself suffers from a less-than-optimal design of the fan control circuit. This is fairly similar to the one being shown for the One v2 box. The most important difference is the fan operating voltage - the EON fan runs off 12V. Also the output capacitor seems to be ~7,5uF for the EON (measured with a cheap multimeter).
The EON fan control is located in the display/button assembly.
As shown in the linked One v2 post, the problem is the somehow inadequate averaging circuit consisting of a single capacitor being discharged very quickly by the MOSFET. Ideally, one would use an LC filter to get a really averaged fan voltage and reduced ripple. Since I had no suitable inductance (should be aroung 1mH), I just added a 10 Ohms resistor between the Drain of the MOSFET and the output capacitor/diode. For this, I’ve lifted the Drain pin off the circuit and attached a wire to it.
(This modification does require some general understanding of electronics, a fine soldering iron and a steady hand)
As a result, there’s less ripple on the fan voltage, and a wider range of pulse widths can be used. In my setup I measured:
PWM 100% 50% 20% 10% 9% 8% 7% 6% 5% 4% 3% 2%
U_fan 11.6V 11.1V 10.0V 8.5V 8.2V 7.9V 7.5V 7.0V 6,5V 5.8V 4.9V 3.9V
That’s far from ideal, but much better than with the original circuit.
With the 3% setting, the Sunon fan starts up reliably, although the data sheet specifies a minimum startup voltage of 6V. With 2%, startup does not work reliably (although the fan keeps running).
- Finally, I updated the fan control configuration (/etc/argoneon.conf):
[CPUFan]
53.0 = 04
56.0 = 08
60.0 = 18
65.0 = 100
[HDDFan]
38.0 = 03
40.0 = 04
43.0 = 05
46.0 = 06
48.0 = 07
50.0 = 09
53.0 = 10
56.0 = 25
60.0 = 100
As a result, at almost 26°C room temperature, fan control toggles between ‘off’ and 3%. Noise level is noticeable in 1m distance, but certainly not annoying (for me). Btw.: the noise level is much lower with side panels removed (not noticeable at 3% or 4%) - not quite sure yet why these have such a huge (bad) effect…