[mythtvnz] Possibly dying tuner card? (or something else?)

[Nick Rout]

On Sun, Jul 6, 2014 at 6:08 PM, Stephen Worthington
<stephen_agent at jsw.gen.nz> wrote:
> On Sun, 06 Jul 2014 12:20:39 +1200, you wrote:
>
>>Hi All,
>>
>>I've been running my Myth setup for nearly 3 years pretty successfully,
>>but recently I've been running into a lot of problems with failed
>>recordings. This started out with almost all recordings on the
>>MediaWorks multiplex failing, but it has since started occasionally on
>>the other multiplexes too. From looking at the logs this looks like the
>>adapter is unable to tune and eventually gives up. This appears to be
>>more likely when another recording is already in progress. I've done a
>>couple of retunes whilst this has been going on, but they didn't help.
>>
>>In the last week we have also started to get a lot of interferance on
>>some recordings. Last night this produced a recording which was
>>completely unwatchable due to picture degradation and sound blips.
>>
>>Looking in the log for this recording came up with something
>>interesting:
>>
>>Jul  5 19:25:05 laforge  mythbackend[2881]: W DVBRead
>>dtvrecorder.cpp:1290 (ProcessTSPacket) DTVRec(7): PID 0x3ec
>>discontinuity detected (( 5+1)%16!= 7) 0.57985%
>>
>>This message is repeated 42677 times for this recording! Which fits with
>>the almost constant picture issues. Aside from that myth completed the
>>recording 'successfully', athough another recording which started later
>>failed.
>>
>>Since the hardware and software didn't change since this was working,
>>I'm wondering if this is caused by a slow failure of the TV tuner card,
>>or some other part of the receiver setup (which consists of maybe 10m of
>>cable to the antenna and a Kingray amplifier [with phantom power
>>injected from ground level]). The other option is some real interferance
>>- there is a ham radio operator in the next street who I've always
>>suspected.
>>
>>The relevant details of my system are as follows:
>>
>>OS: Debian Wheezy with deb-multimedia packages for myth, etc.
>>Tuner Card: Hauppauge HVR2200
>>MythTV Version: 0.26.1+fixes20140227-dmo1
>>
>>I've uploaded the log from last nights recordings at
>>http://webworxshop.com/~robert/logs/mythbackend.log.20140705. The
>>recording 'Midsomer Murders' was the corrupted one, whilst the recording
>>'Knowing' failed to tune.
>>
>>I'm going to try and do some investigation with tzap later today and I'll
>>post the results here.
>>
>>Please let me know what you guys think.
>>
>>Thanks in advance,
>>
>>Rob Connolly
>
> When one mux is giving problems, or gives more problems than the
> others, that usually indicates reception problems, rather than tuner
> problems (unless, like me, you have muxes forced to use specific
> tuners).  Usually one mux has the worst signal, either the lowest
> power transmitter, or the highest frequency.  So that mux is the one
> that gives problems first.
>
> I would suspect the cabling first.  Are you using good shielded aerial
> cable (RG6 I think is what is best), and F-connectors everywhere you
> can?  Is there somewhere that another power or signal cable has been
> installed or moved to that runs parallel near your aerial cable?  Has
> a cable been bumped and pulled out partially anywhere (eg while
> vacuuming)?
>
> Check that the power supply to your aerial amplifier is still working
> - they are usually just wall warts and hence not usually the most
> reliable of things.  Visually check that the aerial itself is OK and
> still pointing in the correct direction.
>
> Try using LiveTV and see what the on-screen signal level and s/n
> values show, or use dvbtune.  This is the command line I use for
> dvbtune:
>
>   dvbtune -f $a -qam 64 -gi 16 -cr 3_4 -bw 8 -tm 8 -m -c $ADAPTER
>
> where $a is the frequency in kHz (530000, 562000, 578000 or 594000 for
> Wharite), and $ADAPTER is the adapter number, which is 0 or 1 in your
> case.
>
> Do you have another DVB-T tuner you could plug in for comparison (eg
> USB one on your laptop)?


All good points, the other one is that your antenna could have
shifted. High winds lately? Earthquakes? Similarly a good storm could
get H20 into your cabling.

>
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