[mythtv-users] HD-PVR power supply (wall wart) gone bad

[Allen Edwards]

On Mon, Dec 3, 2018 at 3:28 AM Daryl McDonald <darylangela at gmail.com> wrote:

>
>
> On Sun, Dec 2, 2018, 11:06 PM Bob <mythtv at cox.net wrote:
>
>> On 12/1/18 8:33 AM, Allen Edwards wrote:
>> > Don't use the +12 line.  It will likely destroy the unit. I am very
>> > surprised that the internal +5 supply in a PC ran out of current.  I
>> > could understand that if you got the +5 from a USB cable but not from
>> > one of the molex cables.  Maybe the wire is too small or you actually
>> > hooked up something wrong.  Get a voltmeter and check what is on the
>> > wires when you are recording.
>> >
>> > Allen
>> >
>> > On Sat, Dec 1, 2018 at 5:27 AM Daryl McDonald <darylangela at gmail.com
>> > <mailto:darylangela at gmail.com>> wrote:
>> >     More than doubling the voltage is never a good idea, my guess would
>> >     be not enough amperage, I couldn't get reliable operation from
>> >     internal power supply to a HDHR so I now keep a supply of
>> >     replacement walwarts on hand.
>>
>> Here's a photo of the cable:
>>
>> https://pasteboard.co/HPXIYlf.jpg
>>
>> The Molex connector was taken from a Molex-to-floppy drive adapter
>> cable. The cable diameters seemed similar in size as the Hauppauge
>> cable. I did use the full cable length from the wall wart.
>>
>> I am going to experiment with using another supply line on the power
>> supply. The power supply is only a 500W, hopefully that is not an issue.
>>
>> Thanks for the feedback/thoughts.
>>
>> Bob
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>
> Your capture device is at risk, if that "another supply line" is the 12
> volt one.
>
>>
>> _______________________________________________
>

I will repeat, you will almost certainly burn out your device if you power
it from +12 volts.  I just looked at your cable and it looks fine.
Therefore I would ask why do you think the old supply is bad?  Did you use
a voltmeter or an oscilloscope to test it.  If so, you should be able to
test the output of your cable.  If you didn't test it, and given you want
to put +12 into a +5 device, I would guess you did not test it, perhaps it
is the PVR that is bad and not the power supply.

The other possibility, mentioned already, is that there are ground
problems.  The wall wart is almost certainly not grounding your PVR as the
supply from the computer is.  If your PVR is grounded on a ground of
different potential than where the computer is grounded that could cause
problems. Plug them both into the same outlet and see if that helps.

Allen
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