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Starting Again

Discussion in 'Televisions' started by eglons, Mar 23, 2005.

  1. eglons

    eglons
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    Well I've finally given up on my 36ZP48, I've now had 4 from John Lewis and all of them have had nasty dirty screen issues. They've offered to keep swapping, a full refund or a different TV.

    I keep seeing reviews which say that 36CRT can suffer from this dirty screen phenomenon and this is just no use to me.

    Looking at my requirements :

    1. I watch loads of Sky Sports via RGB Scart. Don't want pixelation issues or dirty screen
    2. I'm happy to go with the sound the set has as I can't run any external
    speakers (children and cabling run issues)
    3. Don't watch a lot of DVD and would be happy to view via SCART
    4. I'd like a biggish screen but will settle for 32 inch CRT rather than go for Rear Proj (too bulky) or Plasma/LCD (kids will knock it over and I don't have space for a wall mount).

    I paid £1200 for the Tosh but I'm beginning to think I'm not really using most of the features so am considering a cheaper 32 inch CRT... any advice appreciated.
     
  2. eglons

    eglons
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    I should have added that I have been very impressed with JL and would like to stick to something they can provide.
     
  3. red16v

    red16v
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    Hi, well this is a difficult one but nonetheless I always thoroughly recommend the Toshiba 32ZP48 - I know that's not what you want to hear. I fix tellys for a living (both domestic and professional) and this model is my own personal choice. As you can imagine I hear about lots of faults on tv's but I have never heard anyone refer to a fault as 'my telly has a dirty screen' - I would really like to know what this 'dirty screen' issue is that quite a few members on the forum refer to - perhaps it is very difficult to explain at a distance and if I were to be shown it on a telly in front of me I might understand ?

    However, we have had our 32ZP48 for several months now and every time we watch it I am always impressed. We use it in its 'Natural' scan mode and watch a reaonable variety of material via Freeview. My only comment I can make about your own set up is that I see you watch a lot of sport presumably almost exclusively via Sky ? Sky uses a transmission system that highly compresses the tv signal - much more so than Freeview which uses the same sort of techniques but with 'lighter' compression. This is particularly noticeable on the 5 main terrestrial channels - SKY compresses them very much, Freeview doesn't compress it to anything like the same degree. Take Sky football, as you will know these are 'linked' back to the Sky broadcast centre for inclusion into the transmission system - these football OB's are also highly comnpressed on the link back to Sky - much more so than those of ITV or the BBC - you can imagine that a signal that is subjected to heavy compresion TWICE is going to be in a bit of a state by the time it reaches your telly. Now, I am not really in a position to criticise SKY but their method of source compression and transmission is the major reason why I would never buy it - perhaps that might change when they start to transmit their local sport/news and movies in high definition. I know there are others on the forum who are very happy with the quality of their Sky reception - but for me I put a question over their entire 'methodology' it seems to be 'pack in as many channels as we can and don't worry too much about the technical quality'. I expect I've opened up a can of worms but no bad thing - that's what the forums about, good luck with your next choice. Regards, yt.
     
  4. CJROSS

    CJROSS
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    Eglons

    Sorry to hear about your problems with the 36ZP48P (my second set is working perfectly FYI) anyway I spent a good while in JLs comparing all types of screens and CRTs to me were where my coins were heading. 32” wise the Panny PD30 looked lovely (component input) the other one was a Phillips 32” TV their latest CRT sets I was told, stunning, no component but from the scart pictures I saw it was pretty superb. Sorry I cant remember the TV mdoel. But it was circa £1000+ IIRC. The Phillips was stunning looking TBH. 32” wise and without need for component inputs I would check that out.

    PS good luck.
     
  5. GalacticaActual

    GalacticaActual
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    red,
    the drty screen effect is noticable on camera pans from left to right against brighter backgrounds. It manifests itself like there is dust or dirt on the inside of the screen tube glass. It is rarely noticable on staic images. Football and other fast moving sports can really show it up as can fast moving pans in movies. It is one of those problems that once you notice it you can not ignore it.
    I am not sure the reason why it happens either, but I belive it is something to do with the sets shadow mask.
     
  6. Wackojacko32

    Wackojacko32
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    Eglons

    The Philips model that CJ is talking about is probably the 32PW9509. I had one of these, terrible dirty screen and a vertical white line down the middle. Sent it back after looking at these forums, just do a search, and other TV's in the shops that all suffered from the same problems. I am now looking for another TV and just daren't try another model.

    Red, I would describe the 'dirty screen' effect as an inconsistency in brightness/contrast across the screen. On my 9509 it was evident on the 'no signal' blue screen but not too bad on normal viewing. As David says football is the best (or worst) at showing this up as the colour/shade of the pitch changes as it passes behind the dark areas.

    Wackojacko32
     
  7. red16v

    red16v
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    Hi, well first of all thanks for taking the time with your explanations - to me it sounds as though it could still be due to the digital picture processing undertaken on the picture - I've watched a fair bit of terrestrial football on my tv but I've never seen anything like what you're describing - perhaps I am lucky ? I am still 'minded' to think that the problem is worse on Sky reception rather than Freeview - can anyone comment on this ?Regards, yt.
     
  8. Wackojacko32

    Wackojacko32
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    Red

    As I said, the dark patches were visible with no signal, plus watching the rugby on terrestrial exhibits the same phenomenon so its not signal related IMO.

    Wackojacko32
     
  9. eglons

    eglons
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    Thanks for the info guys. I can confirm the dirty screen issue I'm suffering from looks just like dust under the glass. It's very noticable on fast pans against a single colour background (football and skiing are awful). I can also confirm that it's easily visible on and AV channel with nothing plugged in (so it's not the signal)
     
  10. red16v

    red16v
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    Hi, ah, well if I understand it correctly then 'we' are saying you can see this even without displaying a broadcast picture and it can be seen on a non-moving background such as a stationary DVD or tv menu. (although when displaying moving pictures the effect distracts from enjoyment of the picture)

    I think the key thing here is saying that it looks as though the screen is 'dirty' - so I would assume that if the tv is displaying let's say virtually an entire screen of 'white' then parts of the screen look as though they need a wipe with a cloth - likely that the 'dirty' areas are not randomly placed around the screen but probably form broad 'sweeps' of dirty areas around the screen?

    If all this is true (?) then the problem seems to me to be one of crt screen purity. Very often people think that a 'lack' of good screen purity will give rise to areas of incorrect colour - this is true at the extreme of poor colour purity but it is the extreme. If the streams of electrons are not guided to land 100% correctly onto their respective phosphors then they will be shielded by the internal shadow mask from their individual phosphors and the net result is a reduction in brightness - you can imagine then that on a pure white picture some areas are not as bright as they should be and you could well imagine that the result would be a 'dirty' looking area of the picture - it is NOT coloured but simply reduced in brightness. (as the electron beam landing is gets worse then electron beams designed to land on one coloured phosphor lands on a colour phosphor for different electron gun and the result is an area of incorrect colour - but as I say this is taking a purity error to the limit).

    I have seen this and it is not un-common on large screen crts. Getting convergence and purity 100% correct on such a large crt is difficult. The efficiency of the electron beam landing process is not uniform across the width of a crt and even on a very well adjusted telly you would almost certainly notice that if the telly was displaying a pure white screen that the 'whiteness' would drop off around the outside of the screen. I suspect that most manufacturers set their tellys up to give a reasonable compromise between purity and geometry - certainly that's what I would do if I were changing a large CRT. There's no doubt about it the larger the crt the more problems you have in achieving that compromise. So, perhaps different manufacturers will have different levels of tolerance ? I would still recommend the Toshiba 32ZP48 ! Regards, yt.
     
  11. GalacticaActual

    GalacticaActual
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    red, i think you have hit the nail on the head there mate :smashin:

    sounds like an exact description of the dirty screen effect to me.

    I did not notice this on my old sony crt. That is not to say it was not there however. The problem is , is that a little knowledge can be a dangerous thing :eek: and once you start looking for problems you normaly find them :suicide:

    One of the rewasons I went for a plasma is that there is no dirty screen effect on them :smashin:
     
  12. eglons

    eglons
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    Red, this is exactly the description I've heard and seems correct to me. The problem is that I've now had 4 Tv's and none of them have been acceptable (all have had the dirty patches in central areas of the screen and it's not watchable). JL have offered to replace with a different model but they don't do another 36inch CRT so I'm going to have to keep swapping until I get one which is acceptable.
     
  13. eglons

    eglons
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    My 5th Tosh turned up on Monday and it's miles better than any of the others, one very small patch and one very faint line (both only really visible on blue screen) at last I can enjoy the TV!
     
  14. red16v

    red16v
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    Hi, I am pleased that now you are a satisfied customer, your patience has been rewarded. Regards, yt.
     

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