[mythtv-users] PVR 350/500 problems (garbage in video, pulsating audio)

Ronald Frazier ron at ronfrazier.net
Wed Apr 30 00:24:42 UTC 2008

My mythbox has 2 analog cards. A PVR-500 and a PVR-350. I've got 2 problems.

First problem:
Ive noticed lately on the PVR-500 that the audio in the recording has
a pulsating sound to it. It sounds almost like someone is slightly
turning the volume up/down about 2-3 cycles/second. I can't hear it in
normal dialog and sfx...only in continuous tone audio. Here's a clip:

Ive tested and it happens on both tuners of my PVR-500, but it doesn't
happen on my PVR-350. Now, the encoding is done onboard in hardware,
and I can hear the same pulsating when playing it back under windows,
so I really don't know what myth could be doing to cause it. I'm more
inclined to think it's a hardware issue, but I'm hoping someone can
suggest something.

Second problem:
My PVR-350 has a graphical glitch that's happend to it twice over the
last 6 months. What happens is that you get a bunch of blockiness at
the top of the screen, and it flickers twice in a row (about 1/4 of a
second apart), and repeats this about once per second. Here is a

And here's a video (due to the framerate of the capture, you can only
see one half of each pair of flickers):

It almost looks like something to do with closed captioning, but I
don't know what could be causing it. It will work fine for months and
then just happen out of the blue. The last time it happened, nothing I
did made it go away short of rebooting (or maybe even a full power it
down...I don't recall). It's currently happening right now. I'm gonna
try not to reboot it in case anyone has any suggestions (as it may not
happen again for months).


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