A fine line between love and hate

[Zaichik]

I recently bought a Panasonic TX28DTX10 28" 100Hz IDTV, and I've noticed that the fine lines of phosphor dots that make up the picture are more widely spaced at the left and right of the screen than at the centre and consequently they become visible over certain colours, even from normal viewing distance. The effect is rather like a fingerprint on the far right and left of the screen. Now I've noticed it, I can't unnotice it. :(

An engineer from the store I bought the set from came round today and said that this was perfectly normal and just how the tube was manufactured. However, I've never seen it on any other set that I've owned (or, indeed the demo models of this new set in two stores that I went into to check before he came). Surely, you shouldn't be able to see the lines of the screen from your sofa?

I'd be grateful for any views on this because I'm not sure what to do. :shrug:

[Damian Arstall]

Think I know what you mean.

The only tubes I've seen that don't seem to suffer from noticable phosphors to the edges of the screen are Sony tubes.

My folks have had Panasonics from a few years ago and its never been noticable but I think using flat tubes shows them up now. My last 100hz Panasonic was the same but when the rental came up for renewal I went back to buying a got a Sony.

If it helps I personally think JVC and Philips look worse for this problem with Panasonic being only just noticable.

:)

[Zaichik]

Thanks (belatedly) for your advice

I've just had a Panasonic authorised engineer out to look at the set, after the store's engineer couldn't (or wouldn't) see what I was describing. The Panasonic engineer could at least see what I was on about. He's going to consult with Panasonic and see what can be done. I wouldn't mind if the patterns/lines were only slightly visible, but they're blatantly obvious even from some distance away, and they're spoiling my enjoyment of the set.

I'm expecting the engineer to come back and say that it's within specification, but whether it is or it isn't is of no interest to me a) because I don't want a set that has this "feature", particularly when b) I've seen 2 identical sets in different stores (and lots of others of different makes) which didn't have the same problem.

I'm really cheesed off about this. :brickwall :mad:

[ljp]

Didn't you notice before you bought the tv in the first place?

[Zaichik]

As per the post above, the demo sets did not have this problem (or at least not that I could see when staring hard). Mind you, a lot of stores seem to make sure that their demo sets show fast moving images, which makes defects like this hard to see.

However, I didn't notice it on my set until I'd had it for a couple of weeks. Now I can't stop noticing it! :doh: I was watching HeadJam last night and the diagonal lines covered almost half the screen at times on the purple backgrounds. I realise that visible phosphors are a common feature of widescreen sets, but surely no-one can really think that lines covering half the screen is acceptable. :cuckoo:

[Nick dVl]

I'm curious - can you post a pic of the problem?

AFIAK, a lot of tubes used by other manufacturers are, in fact, Philips tubes - which is why I stay clear of anything non-Sony (they have their faults too, mind you...).

[craigizmo2k2]

My philips and jvc widescreen tellys have no such problems :|

[Zaichik]

I'm curious - can you post a pic of the problem?

AFIAK, a lot of tubes used by other manufacturers are, in fact, Philips tubes - which is why I stay clear of anything non-Sony (they have their faults too, mind you...).

I'm afraid I don't have a digital camera, and I don't think it would come out anyway.

I can't decide what to do - I went into another store this weekend, and almost all the demo TVs seemed to suffer from this problem to some degree. I suppose I could continue to press for an exchange and hope the next one was better, and not worse in some other way. :thinking:

[Wayne Moule]

My Philips sets have done this and I've put it down to the picture being stretched out to widescreen. It doesn't bother me as much as other flaws in sets.

[MrBoombastic]

It sounds like you're describing a moire (pron. mworay) interference pattern. Illustration (http://bic.beckman.uiuc.edu/mriartgallery/artifact/moire.gif)

I had exactly the same problem on a 32" Panasonic I bought a couple of years ago, but only on R1 DVDs. After much arguing with the retailer (they insisted that it was 'cos the TV was incompatible with non-R2 DVDs :doh: ) I finally got them to replace it with a Philips which is fine.

[Zaichik]

You may be right.

The Panasonic engineer has just phoned me - he says that the problem is moire and that little can be done about it. Panasonic's official line is that increasing the width and height of the picture may help. I mentioned the advice that someone posted on the AV forums about defocusing the tube and he said that Panasonic did not recommend this.

He's going to do me a report to take back to the retailer. If the Panny engineer's advice is correct, I think that the problem may have been exacerbated by the shop's engineer who came to adjust geometry. He messed about with the picture size, despite me only asking him to correct some bowing at the sides. This may explain why I did not notice the problem until after that first visit.

[MrBoombastic]

I suspect you're right. Prior to me returning my Panny in exchange for the Philips I fiddled with the service menu and adjusted the geometry, I was able to reduce the problem but not eliminate it, so adjusting the geometry certainly can alter the effect.

[Zaichik]

I think I've got the retailer riled! I sent them a long and detailed letter, quoting the Sale of Goods Act, and it's clear from the phone call I received this afternoon that they're investigating my version of events, probably with a view to shooting me down in flames! I'll 'ave 'em - I will. :lol:

[Zaichik]

VICTORY!!!


A "second line" engineer from the store has just been and he's accepted that there's a fault with the tube. They've agreed to exchange the set. :D :D :D

I just hope the next one's not worse! :eek:

PS It wasn't moire after all.