[mythtv-users] HDHomeRun Prime iPad app

[Mike Perkins]

On 20/08/11 18:16, James Van Vleet wrote:
> On Fri, Aug 19, 2011 at 5:20 PM, Raymond Wagner<raymond at wagnerrp.com>wrote:
>
>>> it makes sense to remove as much unnecessary weight as possible.  No,
>>> this is just some marketing weenie telling the engineers to use external
>>> supplies because a slightly smaller unit will be more appealing and sell
>>> more.
>>
>
> I did a brief stint in the appliance hardware thing and based on
> that experience I don't believe this is the case.  The real reason I
> discovered is that it is *much* less expensive and painful from a UL (or
> other equivalent) standpoint to purchase an already approved UL external
> power supply and feed low voltage into your device.  Doing this can make
> both the initial UL cert and the updates as the device changes a snap.
>
> Otherwise you are feeding 110-220 volts into your device and UL is MUCH more
> interested in those.
>
> Also there is the whole getting that heat out of our device thing, but in
> our case taking a lot of the UL headaches out of the system was the big win.
>
I'd sooner have the heat generated inside the box where the designed-in fan can 
correctly dispose of it than have it generated by a lump of plastic sitting on 
the furniture or on the carpet. (A typical 12v supply for a pico-PSU is a brick, 
not a wall-wart.) Still, I agree with your reasoning as to why they do such things.

-- 

Mike Perkins