[mythtv-users] tranquilPC T2e and EN board running MythTV: hot CPU

[Brian Wood]

On Feb 11, 2007, at 5:09 AM, Udo van den Heuvel wrote:

> Hello,
>
> Since my previous posting about this subject I have been wrestling to
> get the heatpipe working well in the TranquilPC T2e case.
>
> When the VIA EN12000 is running Myth, playing SD TV directly from a
> broadcast, the CPU is 80+% idle.
> CPU temperature rises to 55 degrees Celsius or about 131 degrees
> Fahrenheit in a fairly cool room of 17 degrees Celcius.
> Top of the CPU heatsink does not reach 55 degrees at all even  
> though the
> right (small!) amount of heatpaste was applied and all springed screws
> are tightened to the maximum.
> I checked this many times, as well as the 'hinge' where the heatpipe
> attaches to the side coolblock which could tilt the CPU heatsink
> slightly when not properly aligned.
> Even somewhat loosening the screws of the top heatsinks which clamp  
> the
> heatpipe to the bottom heatsinks, to make sure the heatsink can rest
> flatly on the CPU, does not fix the cooling issue.
>
> This case should cool the CPU on the EN board to 35-40 degrees  
> (Celsius)
> in a 20 degree room, 15-20 degrees lower than the current  
> temperatures.
> Is there a heatpipe expert reading this who can help me fix the  
> cooling
> of this fanless T2e case?

I'm certainly no expert but I've built a lot of machines.

I'd have a look at the surface of the heatsink that contacts the CPU.  
Is it really really smooth? Can you see yourself in it?

The purpose of the "heatpaste" as you call it is to fill in any tiny  
gaps in the interface between the chip and the heatsink, the rougher  
the HS surface the more grease is needed, but the transfer will still  
not be as good as if the gaps were not there.

You can take some emery cloth, or even crocus cloth, or even  
jeweler's rouge and polish the heatsink surface as  smooth as you can  
get it. You should literally be able to see yourself if you do a good  
job of this.

I have seen this make 20 deg. F differences in final operating  
temperature.

Also, I know this is obvious, but clean both surfaces well with  
isopropyl alcohol before applying grease or mating the surfaces.

Theoretically polishing the CPU itself would help as well, but I've  
never done that nor have I heard of anyone else doing it, for pretty  
apparent reasons.