[mythtv-users] I think my HRHR Prime died...

[Richard Shaw]

On Thu, Sep 3, 2015 at 11:07 PM, Stephen Villano <
stephen.p.villano at gmail.com> wrote:

> OK, let's preface this with, I am a certified electronics technician.
>
> OK, a VOM, pretty much *any* VOM will be fooled by ripple.
> DC power in ancient and familiar for me days of analog circuitry, had
> mains frequency hum. Most failed to notice, those that did got extra
> filter caps and occasionally, a massive inductor coil in a pi circuit.
>
> Today, we're in the digital age. A 5 volt supply supplies, with luck,
> 5 volts. What is of import is, sampling rate of the VOM, which is why
> I previously mentioned an oscilloscope.
> One can end up with 2.5 volts *real* DC and a full five volts of
> spikes that result in no useful supply to a logic circuit.
> At 2.5 volts or so, logic goes into an indeterminate state, which
> means getting confused,senile and eventually locked of destructive,
> depending upon the logic usage.
> I've personally witnessed many hard drive physical failures, courtesy
> of a lousy 12 volt supply that measured fine with a cheap VOM, but
> looked like pure DC spikes on an oscilloscope . Later, better VOM's
> had RMS, which was *really* revealing, as there is no sine wave in DC.
>
> Hence, my suggestion at first to try a new power supply.
> No need for detailed comprehension of two years and change of
> electronics school, no 40 years of experience and no requirement of
> more advanced electronic diagnostic equipment that you'd also have a
> massive learning curve to learn how to utilize.
> Based upon my experience and many, many, many other users of the HDHR
> Prime, swap out the power supply.
> If you're as proficient as I am, replace the defective filter
> capacitors. I've done that, via measures that'd give my fire marshal a
> stroke, but the caps got replaced.
> Assuming that you also own an ESR meter, to find the defective capacitors.
> Mine is aging, when it fails, I'll go straight to replacement.
> The cost isn't worthy of the benefit.


Thanks for the explanation! I don't have a fancy Fluke meter but it's a
half-way decent Extech True RMS meter. When reading VAC (in mV mode) it
shows 0, as well as if I try Hz, but I'm not sure what the input to the
meter is supposed to look like for cycles...

Thanks,
Richard
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