[mythtv-users] Desk Top Power

[Mike Perkins]

On 16/05/15 14:21, Daryl McDonald wrote:
> On May 15, 2015 11:20 PM, "Gary Buhrmaster" <gary.buhrmaster at gmail.com>
> wrote:
>>
>> On Fri, May 15, 2015 at 8:18 PM, Eric Sharkey <eric at lisaneric.org> wrote:
>>> On Fri, May 15, 2015 at 4:08 PM, Gordon McCrae <gordon.mccrae at gmail.com>
> wrote:
>>>> Perhaps I'm missing something here, but why not just spend £10 on an
> "Energy
>>>> Saving Master Slave Extension Lead".
>>>
>>> I think that's covered by Daryl's previous response:
>>>
>>>    A quick look and apparently its not available on this side of the
> puddle :-/
>>>
>>> I took a quick look as well.  None of the units I could find were for
>>> North American power.  All the hits seem to be for use in the UK.
>>
>> I think on this side of the pond, the magic words are
>> "autoswitching" and "outlet", although some hits
>> were clearly not what you might be interested in,
>> some appear to be.
>
> Wow, the enormity of knowledge on this list never ceases to amaze me, many
> thanks to all contributors.
>
> My STB is 12 VDC wallwart supply and the switch and HDHR are both 5VDC
> wallwart supply, my initial thoughts were snip and wirenut connections with
> cords from retired units. my hesitancy comes from warnings that "flaky"
> power could damage the HDHR and I assume other components as well.
>
> The relay idea interests me IIUC the power of the PC holds the relay in the
> closed position feeding a power bar with my wallwarts plugged in, and opens
> when the PC shuts down?
>
A "retired PSU" on its own may not do what you wish, since most are designed to 
work correctly under a certain minimum load.

I had a board that I wished to use diskless - PXE booting - but some fairly 
standard PSUs in that box wouldn't even give me a BIOS page. Turns out they 
needed a hard disk as a load to get the +5v working correctly.

These days hard disks use so much less power that I think PSU designers have to 
take that into account, but older supplies may still surprise you.

-- 

Mike Perkins