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Panasonic PK25 - Moire ?

Discussion in 'TVs' started by Mark Buckley, May 21, 2001.

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  1. Mark Buckley

    Mark Buckley
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    Dear All,

    I've a problem with a recently purchased Panasonic 32PK25, I have weird wavy off horizontal pattern lines across the all of the picture except the last 1/4 on the right. I don't know how to describe them really but they are in a wave pattern opposite top and bottom .

    I had an engineer out twice and he couldn't sort it, so I've just received a replacement, which is exactly the same. There are two weird properties of this effect though:

    (1) Completely disappears with a NTSC signal

    (2) The curved lines become straight and much less noticeable if you switch the TV into Just mode, any other mode and the lines are curvy again. Still there, and not there in the last 1/4 on the right, but much less noticeable.

    Really annoying on an otherwise very good set,

    Is it the TV, bad batch, bad design or some local interference ?

    Any help will be much appreciated,

    Best Regards, Mark.
     
  2. Mark Buckley

    Mark Buckley
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    Bad Net eticate I know to reply to my own post, but I know how to describe the effect , like a thumbprint,

    regards, Mark.
     
  3. encaser

    encaser
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    couldn't say for sure what prob is, but I think the pk20 suffered from this effect when pin 19 of the scart was live - i.e. cross talk from Sky box etc. getting through. Try snipping it on an old/cheap scart if you ahve one as a test. Also see the threads further back on here for pk20's 'cause it's worth bearnig in mind that your set is essentially a pk20 with slight appearance mods. Further, take note of MR D's posts on the subject - also in pk20 threads, or ewmail him - 'cause he is pretty much the expert on your set and others. Nice guy actually bothers to reply!
    All the best
    Encaser

    p.s. who nicked my fifth star!? :cool:
     
  4. Mark Buckley

    Mark Buckley
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    If only the only changes from the 32PK20 were cosmetic (as according to Panasonic), can you count the loss of 1 scart input as a cosmetic change ?

    One thing I have noticed is that in 16*9 or 'WIDE' mode, I seem to loose .75cm off either side of the screen, appears if you go into 'JUST' mode. Could this be the cause of my horizontal lines, some interference due to the picture going off the side ?

    Mark.
     
  5. Mr.D

    Mr.D
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    Ok problem is most likely moire patterning. This can happen on any tube apart from the sony trinitrons (or clones) which have a slot mask (or aperture grill!)instead of a dot mask. (they also have visible support wires on the tube)

    I suspect the reason moire is becoming a problem on these sets is because they have to deal with different picture aspects and raster sizes and this is showing up some less than constant focusing on the scan beam or some variation in the dot-pitch of the shadowmask.

    Moire on ANY TV set should be rectifiable by defocusing the scan beam slightly so that its slightly larger than the dotpitch of the shadow mask. I'm assuming for these sets this has been done at the factory but only with relevance to the centre of the screen (makes me think its the dot-pitch on the tube thats not uniform across the width of the face rather than the beam itself)

    So how to fix: get an engineer to defocus the beam with relevance to the edges of the screen and pray that its not so drastic as to really soften and knacker the picture in the middle. Otherwise new tube with more uniform dot-pitch on the shadow mask.
     
  6. Brian Storm

    Brian Storm
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    The Panasonic PK25 is a Euro4 chassis while the PK20 is a Euro5 chassis a similiar set to the PF10, so cosmetic difference is somewhat misleading as the insides are totally different.
     
  7. Ewok

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    I got a pk20 and had exactly the same problem mark described in the first post. I dont think it is what people refer to as moire as its there all the time, not just on certain broadcasts, its there on tv and dvd. It also isnt interference, for me anyway. I looked at a few in the shop and they also looked the same. I have been told by 1 person that this is what all the quintrix screens look like, and from what I have seen in the shop this is true.

    I got a sony now and looking at the sets in the shop, its not just the panasonics thats uffer from this strange pattern on the screen, a fair few others do too, but NEVER on the sony's.

    I am now looking at trying to somehow afford a sony KV32FQ75.
     
  8. Brian Storm

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    Had the wavy line problem on the 32PK25. It was caused by the two focus controls being slightly offset ( dynamic focus and static focus ). A quick simple adjustment puts it right.
     
  9. pmrichter

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    I have the panny 32pf10. Would you be able to explain how you made the ajustments to the two focus controls to stop the wavy lines? I know that that procedure might not be exactly be the same, but it'll give me an idea of what to do. Every set I have had, I've had to go inside to set them up correctly, whether it be to adjust the size or picture quality. It really is annoying that companies cannot set-up there sets correctly, especially when you're paying a vast amount for them. :confused: :confused:
     
  10. Buckster

    Buckster
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    OK, getting a bit annoyed with Panasonic TVs now ! After my original post, engineer came round, couldn't fix it, replaced TV, with a worse one, bad ghosting, bad geometry etc. Anyway, had another replacement yesterday, and picture quality is much much better, plus no ghosting, but still these thumbprint type lines across the screen, mostly on pastel type colours. Confirmed with the engineer that it is not intereference as the TV I returned did the same thing at the shop. Surely must be a manufacturing design fault ? Any ideas anyone ? Can't possibly be three TVs with exactly the same fault. Why has no-one else with 32pk25s spotted this yet ?
     
  11. Monster

    Monster
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    I was about to post a similar topic to this. I have got a Panny TX32 PK1 and suffer with the wavy pattern (Looks like the colours on the surface of a soap bubble?) I also get a green line down the left side of any 4:3 DVD via RGB.

    The engineer came out last Friday and could't fix it. They returned yesterday and took it away to the work shop. The engineer said that they have contacted Panasonic and they said they are not aware of this problem!!

    Has anyone ever had the problem fixed or does it look like a new set will be required? Is the PK1 still available? If not I might swap for PK25. (Got used to the PK1 and have started noticing the flicker more and more.) I notice form the HCC review of the PK25 that the usual problems with 100Hz are not evident with this set?
     

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