Panasonic DMR-BWT850 BD/DVD recorder problem

[JBR]

Hi,
I have noticed that, occasionally, a timer recording I have set on this unit fails to record for some reason. I would put this down to some external problem, such as the transmission being cancelled, but my old recorder - DMR-BWT720 - has recorded the same programme correctly.

On Monday, therefore when the same problem occurred, I made a note of exactly what had been set (on both units):
1830 – 1900 BBC2 Great British Railway Journeys
1900 – 2000 Horror Star Trek TNG
1930 – 2000 ITV Coronation Street FAILED TO RECORD
2030 – 2100 ITV Coronation Street
2030 – 2100 BBC2 University Challenge
2100 – 2200 BBC2 Collateral
2100 – 2200 Ch 4 24 Hours in Police Custody

Clearly, there has been no attempt to set more than two programmes at the same time and, more importantly, my old recorder did record all programmes correctly.

I wonder whether there may be some obscure setting that I have failed to notice. Is it possible, for example, that if I was watching a third channel at the time (1930 in this instance) the recording would not take place for that reason? My experience in the past has been that if this is the case a message would appear on the screen warning that a recording is about to begin, although I didn't see such a thing on this occasion. I haven't seen anything along these lines in the settings menu.

I'd be grateful if anyone could offer some advice about this. The unit is still under warranty, but if it is simply a matter of changing some sort of setting, that would be a better alternative to having it repaired and, possibly, finding all previous recordings deleted!

 

[Lucid]

Like most Freeview+ PVRs, your Pana 850 has two tuners. Strictly speaking that means your choices should be "Record one channel, watch another" or "Record two channels but machine has to be in standby" or "Play a previous recording while two channels record simultaneously"; and that would be the case if we were dealing with analogue tuners, but we aren't. Your recorder has digital tuners and they work a little differently.

Digital TV puts a package of channels in to a multiplex signal - a "mux" - and sends them in what would have been the frequency for just one analogue channel. For example, if your local transmitter is Winter Hill then you'll receive PSB 1 (BBC A) on ch. 50 (706.0MHz) and that mux package provides BBC One North West, BBC Two, BBC Four, CBBC, CBeebies, BBC News, BBC Parliament, BBC Red Button, plus a whole bunch of Freeview radio stations.If you happen to be recording one of the TV stations in this list then that same tuner can allow you to watch any of the other channels from the same mux. Here's the mux list for Winter Hill LINK

If we extend this idea further and look at both digital tuners together, and say you were recording from PSB 1 and also from COM 4 at the same time, then it should be possible to watch another channel from either of those mux groups while two recordings are being made simultaneously. However, what you couldn't do was record from PSB 1 and COM4 and then go watch something from the PSB 2 mux without buggering up one of the two recordings.


Now we have a look at what you were recording on that Monday evening. The SD Muxes time planner shows that at 7:30-8:00pm you'd have been recording from PSB 2 and COM4 at the same time. That means if you tried to watch a 3rd channel that wasn't from either of those two muxes then one of your recordings would have failed.

For the HD muxes it looks a little simpler. There's only PSB 3 and COM4 in play at the same time, but the same restriction applies: You can only watch a 3rd channel live if it comes from one of those two muxes.

Your other recorder might well have made the 7:30-8:00pm recordings fine because you weren't asking it to show you the signal from a third mux whilst recording two others.

 

[JBR]

Thanks, Lucid.

That explains things very clearly. I have, of course, heard of multiplexes but was never sure which channels are part of each multiplex. Perhaps there's a list somewhere!

Yes, that would certainly explain why the older unit didn't fail to record. However, I was under the impression that a message would appear on the screen when a second recording was about to start and that the channel I was watching at the time would be changed to one of the recording channels. I'm sure I have experienced this before.

However, I don't doubt your reasoning for one minute and shall make sure I am not watching a third channel when two others are about to record, or at least watching on the other unit or directly from the television's tuner.

Thanks again. Much appreciated.

 

[Lucid]

Yes, there is a list. I put a link to such in my first reply to you. Did you not bother to follow the link to have a look at the extra info?

The muxes carry the same stations regardless of where the transmitter is located. Two main things change though. First, the frequencies. For example then, PSB 1 carries the same stations but is on ch.50 (706MHz) at Winter Hill, but on ch.23 (409MHz) for Crystal Palace, ch.22 for Belmont. The allocation of the channels is done so as to avoid two or more adjacent transmitters interfering with each other.

The second thing that changes is whether your local transmitter is a main- or a relay-transmitter. Main transmitters carry the full compliment of muxes. Relays carry only the PSB (Public Service Broadcasting) muxes and so they run a reduced service. You'll know from your channel listing whether you're on full service or Freeview Lite.

It's nice of you to say thank you in your reply, but it's far better to show your thanks by using the THANKS button. It costs you nothing, and it marks good info for others who might come across these replies from a Google search. Make it a habit to mark each useful reply with a THANKS and you'll find that you get some in return too. Looks like you're not unacquainted with it as you're currently carrying 359 THANKS received. Spread the love

 

[JBR]

Sorry, I missed your link. As it happens, I have gone to the trouble of making a complete list of all the channels I am likely to use (which doesn't include such things as shopping and dress making channels!) for my future reference.

I've also clicked the 'Thanks' button for each of your posts. Sorry, I should have thought of that sooner.

 

[Princethorpe]

i know it's a long time after the explanation but for clarity for the less technical. I have a pana 655. Will any attempt to try and watch on the Tv a progam from a different mux cause one of the recording channels to fail? Or a timer record not to start . Doesn't the requested viewing channel use the TV tuner and the recorder just passes through the raw sig untouched and doesn't decode? It's only in the last month I"ve been having problems.