[mythtv-users] Heat issues with USB ATSC tuners?

[Devin Heitmueller]

On Thu, Aug 30, 2012 at 2:17 AM, rsh1k <roland.sh1000 at gmail.com> wrote:
> I'm looking to purchase 2 or 3 USB ATSC tuners for OTA TV in the USA,
> but each time I find a "good" one, I start finding issues & caveats...
>
> I recently found the Hauppauge/Pinnacle PCTV HD Pro Stick (801e),
> which is probably the cheapest one that gets good reviews and appears
> to have consistent Linux support.  I have also heard good things about
> the more expensive Hauppauge WinTV-HVR-950Q.
>
>
> However, both of these units are reported to get extremely hot - too
> hot to hold in fact.  So hot that people have even modified their
> tuners to add external heatsinks!
>   ->  http://www.john-am.com/2011/01/modding-a-hauppauge-wintv-hvr-950q-with-heatsinks/

Yeah, this is just nuts.

> Of course, producing this much heat also means that they are using a
> lot of power...  which is something I am trying to minimize on my next
> build.
>
> Can anyone tell me if this high power / high temperature issue is
> unique to the Hauppauge/Pinnacle designs?   Does anyone have a usb
> tuner that runs cool?

No, this is common practice.  There is nothing unusual about these
sticks.  The reality is that it takes a good bit of horsepower, and on
PCI/PCIe tuners the heat is just as much but it's more dispersed by
the PCB acting as a heatsink.  Also, it's internal so you're not
typically handling the device during operation.

Even as the user who modded his 950q pointed out, there was no visible
difference in performance.  This is just a case of somebody sticking a
heatsink on something just because they can.

The devices in question draw less than 500ma @ 5V during operation,
which is the limit set by the USB standard.  In fact, I've taken
direct power measurements and compared them against the devices under
Windows as well as other tuner products.

Go to any modern LCD television and grab the F-connector that the coax
cable is connected to (leave the coax disconnected for a few minutes
though since it can act as a heatsink).  It will burn your fingers
just as much.

Devin
(the guy who did the 950q and 801e Linux driver support)

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com