PANASONIC DMR-E85H-help re intermittent drop in recording quality on hard drive

Discussion in 'Blu-ray & DVD Players & Recorders' started by mcphert1, Apr 27, 2007.

  1. mcphert1

    mcphert1
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    Hi
    This is my first post, so I hope I have done it right. After about three years of owning the DMR-E85H hard drive dvd recorder, and lots of recording from the internal tuner to the hard drive, I have recently started experiencing a big deterioration in recording quality. In effect, the picture goes from good quality to being extremely grainy. The recording can commence ok but can switch to this poorer quality out of the blue during the recording. Currently about a third of programs will record normally, a third will be this poorer quality, and the other third will start out normal and then switch during the recording to this poorer quality.

    I tried completely erasing the hard drive but this did not help. I might also say that I do not believe it is an aerial problem, as you can watch the internal tuner channels without this happening. I have to therefore deduce that it is a problem with the hard drive.

    Have any others had this problem and are there any fixes?

    Thanks for any help you might be able to give.

    mcphert1
     
  2. Gavtech

    Gavtech
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    Welcome to the forum.

    This is certainly a weird one... and not a fault I have ever heard reported before.

    A few questions:

    When the fault occurs - does it instantaneously switch into the fault mode or decay into into it?

    Are you certain that it is a recorded issue and not a playback fault ... in other words - Is it repeatable - Can you rewind to the point of failure and the recording behaves as it did the first time.


    This is a very puzzling way for data to degrade... and even more puzzling that the straight through output of the tuner does not exhibit the problem... but is a useful indicator of the sections that may be concerned.

    I am very doubtful that this is a fault of the hard disk.

    The problem here is that this might be traceable by a competent engineer with good analytical skills ... but they are thin on the ground these days... and the analysis could prove costly... unless it happens to be a stock fault with a known remedy.

    What I suggest you do is contact the technical department of Panasonic Customer services... Contact points at the bottom of this page here:

    http://www.panasonic.co.uk/customer-Support/index.asp

    ... describing as accurately as possible the kind of quality degradation that occurs ... and the circumstances under which it happens , and see it they have encountered it / can throw any light onto it.

    Good luck.
     
  3. mcphert1

    mcphert1
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    Thanks GavTech.

    In answer to your questions:

    Q. When the fault occurs - does it instantaneously switch into the fault mode or decay into it? -
    A. INSTANTANEOUS. THAT IS, ON THE HD, THE PICTURE GOES FROM SP MODE QUALITY TO VERY POOR GRAINY.

    Q. Are you certain that it is a recorded issue and not a playback fault ... in other words - Is it repeatable - Can you rewind to the point of failure and the recording behaves as it did the first time.-
    A. IT'S REPEATABLE - DEFINITELY THE CHANGE IS REPEATED WHEN YOU REWIND ON THE HARD DRIVE.

    It's got me beat too. But I am inclined to think it is the hard drive, because the loss in quality when you watch the tuner channels is fine, it is only what is recorded on the HD.

    I might also say that as per my original post, the change only occurs about one third of the time, and usually only once during the recording period. That is, it is not switching back and forth on a regular basis.

    Any further comments would be appreciated.

    mcphert1
     
  4. Gavtech

    Gavtech
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    I really find it hard to believe that the problem could be anything to do with the hard disk... despite it only occurring under the circumstances you describe.

    The data that comes out of the encoder is in a highly complex packeted form ... and if there was any problem getting data on or off the disk then I cannot help thinking that you would just get no results at all. A corruption in the data would make it impossible to reconstruct an image.

    I am inclined to think that there might be an issue with a power line somewhere ... Recording is likely to be the machines highest power demand which might be heating and tripping a component into a fault mode - such as a dry cap... or diode ... even a voltage sub regulator which are known to cause a variety of difficulties in these machines.

    However - Such speculation is not much use to you. Basically I don't know what the problem is here.
    I really think contacting Panasonic is worth a shot.
     
  5. Hal_loe

    Hal_loe
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    Could the effect you are seeing be the video resolution dropping as per how the Hybrid VBR works?

    With the E85 it is possible to switch the Hybrid VBR from auto to fixed.

    It might be worth a try to see if this is causing the problem.
     
  6. mcphert1

    mcphert1
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    Hal Ioe

    Thanks, the hybrid VBR was already set to fixed.

    Gavtech

    Also thanks. Your view that it is not the hard drive does tend to provide some measure of reassurance, as I would have thought that once the hard drive goes it's all over red rover.

    Additional info:

    I should add that the problems I have experienced occurred about a week after replacing my tv with a Sony 1080p Bravo digital TV. The Panasonic is connected to the TV via component outs. I did not mention this previously, as it would not appear to be a cause, given that the picture from the recorder tuner has no such problems.

    I will keep working on it, and will contact Panasonic if I can't resolve the issue.

    mcphert1
     
  7. mcphert1

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    Fixed problem! As I said below, the problem coincided with the installation of a 1080 Sony Bravia digital LCD TV. I had a new aerial installed and the guy ran that into the Sony and then into the Panny. I changed the aerial to first go into the Panny, and ran the out aerial to the Sony. Fixed it. Not sure why though. Because the picture on the Panny analog tuner looked fine when viewing live, it only intermittently deteriorated when recorded and played back on the hard drive.

    I hope my experience might be useful to others out there with this problem. It may also be an emerging one as the 1080 Tv's are relatively new (and few) here in Australia.

    Regards

    mcphert1
     
  8. maldonian

    maldonian
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    Based on your description I would guess that (a) the Sony tuner is adding spurious signals or noise to the RF loopthrough output, and that (b) these spurii change, or come and go, when you change channel on the Sony, and that (c) when the E85 is connected after the Sony, the spurii can cause interference on the channel the E85 is tuned to. This could explain why your recordings were only affected for some of the time - you sometimes changed channels on the Sony while recording (and also perhaps not all channels on the E85 were affected). The only thing that's not explained is why the E85's tuner output always looked ok. Perhaps every time you monitored the recorder's output you always happened to leave the Sony tuned to a channel that didn't caused interference, or perhaps the Sony didn't produce the interference while it's tuner wasn't selected.

    But it's all just a guess, there might be another explanation.

    It's unusual for a TV to have RF loopthrough. In my experience they normally only have an aerial input and have to be at the end of the line. (But I must admit my experience doesn't include modern flat panel TVs.)
     
  9. Gavtech

    Gavtech
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    Indeed - it is certainly a weird one this! I have never heard of a TV with loopthrough either... one wonders what the intended point of that is:confused:

    Odd that an installer would configure it in such a way too.

    However .. I am pleased your issue is now sorted out mcphert1.
     

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