[mythtv-users] HDPVR problems - power supply again?
stephen_agent at jsw.gen.nz
Wed Aug 14 10:36:54 UTC 2019
On Tue, 13 Aug 2019 20:39:24 -0700, you wrote:
>> Has anyone ever hooked up an ammeter to see what the HDPVR actually
>> draws? I
>> wonder if it is close to the 2 AMP rating of the PS, so just stresses it
>> causing earlier failures.
>I had the same thought last time mine crapped out. Instead of doing the
>science as you propose, I replaced with an over capacity wall wart (3-4A I
>think) and that's the one that just failed.
>I don't know enough about PS electronics to say if anything other than
>over-drawing current could stress the PS.
>It also makes me worry about getting power from the USB of the Myth box.
>It's one thing to kill a $15 wall wart and another to kill a $100 PC power
PC power supplies are usually very robust, and typically are running
well below their rated capacity. If you buy expensive ones, they
usually have a list of the protections they provide (over voltage,
over current and so on). USB ports have limits in their circuits to
prevent anything from drawing too much power - that is part of the USB
standard. So the real problem with using a PC power supply only comes
if you connect the HDPVR to a standard power connector (ether Molex or
SATA) and do not have any current limiting in the connection you use
(such as a properly rated fuse or circuit breaker). The PC power
supply can then supply a great many amps into the HDPVR, and if the
HDPVR has a fault that draws huge current, that can cause a fire.
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