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On fan cleaning

everthewatcher

everthewatcher

Forum Supporter
I'd noted the HDD temperature on the main T2 had started to run a few degrees hotter over the last few months. Nothing dramatic, say a rise of 15C over ambient instead over 10C (35C vs. 30C). The fan package is installed, set to a minimum of 49% (it doesn't like 50%) so it's running all the time. It's a V2 with the fan blowing inwards and it's got a slot cut in the HDD frame to direct some fan airflow over the main chip's heatsink.

Finally pulled it out, expecting to see a fairly clogged or even stopped fan, but it was running OK with a very fine coating of dust on the back of the blades. Cleaned it up, put it all back together and there was the expected 10C rise again.

I'm now tempted to remove some of the metal grille.
 
everthewatcher said:
I'm now tempted to remove some of the metal grille.
Click to expand...
Why?, you are well below what the SMART data considers to be the warning threshold and you might not get it any cooler even if you removed the case entirely.

My system normally runs in the low to mid 40s
 
Why not Myms, and I think you have partly missed the point Myms. It wasn't the temp it was the temp difference caused by a light coating of dust.

What I would like to know is what does "It doesn't like 50%" mean.
 
Whether it was fixed about a year ago or not:
What I would like to know is what does "It doesn't like 50%" mean.
 
MymsMan said:
Why?
Click to expand...
Because I've cut a slot in the HDD frame to direct some airflow over the Broadcom chip. Less restriction on the fan airflow should result in even more airflow over it.

Sometime in the past I posted some figures on fan direction and HDD temps, plus the effect of the slot in the HDD frame.
 
everthewatcher said:
Because I've cut a slot in the HDD frame to direct some airflow over the Broadcom chip. Less restriction on the fan airflow should result in even more airflow over it.

Sometime in the past I posted some figures on fan direction and HDD temps, plus the effect of the slot in the HDD frame.
Click to expand...
But is the current temperature causing you a problem that needs to be solved by surgery?

ps 50% changes to 49% for me but I usually have it at 55%
 
Last edited:
Maybe.

Integer(255 x 50%) = 127​
​
Integer((100 x 127)/255) = 49​

But:

Integer(255 x 49%) = 124​
​
Integer((100 x 124)/255) = 48​

...which suggests setting 49 should then display 48, so there must be something more subtle going on.
 
Thinking about this what may be going on is not that the dust itself was directly affecting the airflow, but instead was slowing the fan. At the 50% speed setting it may be right on the edge of working, hence the Humax software's lowest speed of 55% which I've now set it to.
 
Black Hole said:
No chance. If the fan doesn't work right down to a few percent, you need to clean the bearing or replace it (as per my article).
Click to expand...
My point is at 50% PWM it may be getting to the point in its torque curve that a slight increase in drag will slow it far more than at higher PWM.
 
Black Hole said:
Maybe.

Integer(255 x 50%) = 127​
​
Integer((100 x 127)/255) = 49​
...
Click to expand...

/mod/webif/plugin/fan/update.jim

Jim Code: 
#!/mod/bin/jimsh

source /mod/webif/lib/setup
package require cgi

httpheader

set mfcf "/mod/boot/fanspeed"
set fanspeed [cgi_get fanspeed 0]

set fanspeed $($fanspeed * 255 / 100)

set fd [open $mfcf w]
puts $fd $fanspeed
close $fd

puts "Updated Successfully.<br>"
puts "Fan speed will change within two minutes."
 
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