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Th42px600a Owners! Anyone Passed The "purple Snake" Test?


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I have a TH42PX600A on order and have been reading about the "purple snake" phenomenon on the US 42" models - seems to be occurring in batches and only on the 42" according to the AVS forum...

http://www.avsforum.com/avs-vb/showthread....t=purple+snakes

I plan to check it out on mine when it arrives but thought we should run a bit of an Australian survey here of:

1) does your set have the problem?

2) when was it manufactured & where?

Seems like the standard test setup is "Harry Potter, The Goblet of Fire, Chapter One at the 5:10 mark. Harry and his buddies are running up to a boot on the top of a hill and the sky is filled with ominous gray clouds. Check out the edges of the clouds in upper mid screen. Should be visible from 8 to 10 feet away"

Some good pics of the issue here...

http://www.cc.jyu.fi/~jakeisal/pictures/

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Guest spoleweski
I have a TH42PX600A on order and have been reading about the "purple snake" phenomenon on the US 42" models - seems to be occurring in batches and only on the 42" according to the AVS forum...

http://www.avsforum.com/avs-vb/showthread....t=purple+snakes

I plan to check it out on mine when it arrives but thought we should run a bit of an Australian survey here of:

1) does your set have the problem?

2) when was it manufactured & where?

Seems like the standard test setup is "Harry Potter, The Goblet of Fire, Chapter One at the 5:10 mark. Harry and his buddies are running up to a boot on the top of a hill and the sky is filled with ominous gray clouds. Check out the edges of the clouds in upper mid screen. Should be visible from 8 to 10 feet away"

Some good pics of the issue here...

http://www.cc.jyu.fi/~jakeisal/pictures/

all i can say is... mine better bloody not have it!

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All I can say is look out for it when you get your display so you can return it ASAP without too many hassles if it occurs. I had the problem and its no fun at all once you spot it, all you end up doing is looking out for it.

The worst culprit I found was watching The West Wing on the ABC on Monday nights. That show never failed to show the fault.

My new 50 inch is a whole lot better. I can still detect it very faintly on certain occassions when Im up close to the screen but its only about 5% of the problem the 42 inch gave me, so I can live with it.

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OK - questions...

What process did you go through when you noticed it? Who did you buy from and did you have any problems returning under warranty? Interested to know whether Panny in Australia are acknowledging the problem? Did you have to pay the difference to upgrade to the 50"??

Do you recall the manufacture date of your 42" and where?

Whoa - thats a lot of questions...

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OK - questions...

What process did you go through when you noticed it? Who did you buy from and did you have any problems returning under warranty? Interested to know whether Panny in Australia are acknowledging the problem? Did you have to pay the difference to upgrade to the 50"??

Do you recall the manufacture date of your 42" and where?

Whoa - thats a lot of questions...

Hi, Yeh I posted most of that detail in the pana best price thread (posted 31 dec 06). I've copied it for you below.

quote

Had a quick look at the avs thread. The pics showed the exact same problem that I encountered with my 42pv60a bought in August (made in Japan June 2006). Had a hard time convincing the first service centre that it was a genuine problem. Took it to another service centre who diagnosed the problem in about 1 minute. He said the sustain board (if memory serves) was on the way out. However the problem existed from day 1.

Managed to get a refund from Myer and upgraded to the 50 inch. No such problems with the new panel

I'd recommend anyone with a new pana panel to check it for this problem and exchange it ASAP if you notice it. Hope this helps someone.

Quote end

I was "lucky" enough to get a full refund from Myer (less delivery costs) even though it was 4 months post purchase. Once I was convinced it was the plasma at fault and not the source material I notified Myer (about 6 weeks post purchase). But they refered me to pana who refered me to the closest service centre. They dragged their feet and took about 3 weeks just to look at it. They proved to be absolutely useless (long story I dont want to relive :blink: ). Called pana again who recommended a second service centre to check it out. They confirmed the fault as stated above. With that I spoke to the Myer sales manager asking for a refund and he obliged (actually he was quite sympathetic). Not sure if that would've worked at HN :D .

The moral is, check for the fault ASAP so you can return it straight to the retailer if it exists (usually 14-21 days post purchase) no questions asked. Then you wont have to go through what I went through. If you can go through a full episode of the west wing without seeing it you should be ok.

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Bump!

Thanks heaps AndyM - I have taken a 5 year warranty so some comfort there. I will be renting Harry Potter on the way home from picking up my set...

Anyone else want to run the test on their set? Sounds like there are a lot out there so it would be good to get some more feedback...

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Guest spoleweski

I shall put the incredibles and harry potter on as soon as i get it to check for the problem. i really hope it doesn't... maybe its a bad batch thats been released or something? But is it a common problem? is there anyone out there that doesnt have it? because if thats not the case i just wont buy it.

BTW, should I have the tv settings on 'run-in' settings or on full capacity when looking for the purple snake?

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I dunno how common it is - but it seems to be immediately obvious on most sets. It seems pretty prevalent in the UK and US - that's why I am trying to get Australian owners (I know you are out there!) to run a few tests on their sets to guage the problem over here - if it does start to show up this sort of thread will be useful for any sort of warranty stuff...

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Good due diligence, SenojNW. Here's my results as per spoleweski's request.

Pic1. For comparison with the pics above:

HPOF-1.jpg

Pic2. Picture settings at low.

HPOF-2.jpg

Pic3. Auto adjusted - Better

HPOF-3.jpg

Contrast, Sharpness, Color Management, & MPEG NR all affect the degree of this artifact. Contrast makes the most difference as the purple dither effect is worse at low contrast settings. Almost looks like a color space conversion/banding issue, although it's not the same every time.

Edit: Sorry guys, looks like we can't have inline pics.

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Guest spoleweski
Good due diligence, SenojNW. Here's my results as per spoleweski's request.

Pic1. For comparison with the pics above:

HPOF-1.jpg

Pic2. Picture settings at low.

HPOF-2.jpg

Pic3. Auto adjusted - Better

HPOF-3.jpg

Contrast, Sharpness, Color Management, & MPEG NR all affect the degree of this artifact. Contrast makes the most difference as the purple dither effect is worse at low contrast settings. Almost looks like a color space conversion/banding issue, although it's not the same every time.

Edit: Sorry guys, looks like we can't have inline pics.

hey steen thanks for those! You know what, i can hardly see it anyway, if its like that on my set i wont be worried. those previous pictures worried me because it looked so evident.

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Steen

The only one where I could really see anything that looked like it was with picture settings at low - but certainly not as bad as some of the sets in the UK/US...

You happy with the picture?

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You know what, i can hardly see it anyway, if its like that on my set i wont be worried. those previous pictures worried me because it looked so evident.

Please bear in mind that these pics are:

1. P&S at 100ISO.

2. Stills. In motion it may bug you.

3. Downsampled to 1024x768.

4. Have jpeg compression artifacts.

5. Shaky-Cam... :D

I'm usually very fussy with tech details/implementation, but I can live with this panel. On occasions I've noticed colour banding across gradients esp in the horizon/sky (esp Ch7 HD loop - although I do have a high threshold for Sophie Falkiner in a bikini :blink:). I will check out West Wing.

What is the date/manufacture details of your set?

As per here. Dec06 Made in Japan FW v31.040 SW 1.02

The only one where I could really see anything that looked like it was with picture settings at low

Yep. That's the point. Pic1, the typical "boot" scene as per the pic archive above is nowhere near as bad. The worst is Pic2 on the upper left cloud area, but the same still image in Pic3 with the settings as shown improves the image substantially.

You happy with the picture?

Yes. I'm surprised how reasonable it is with settings ~40% max. Colour saturation is very good (an area where LCDs excel). Blacks are very good as expected. Detail is also surprisingly good for an ED panel, although I prefer sharpness at 2-3 stops when HD content is available. There is some grainyness, but not too objectionable and dependent on source/content. MPEG NR at min knocks most of this off on SD/DVD. Certainly nothing I haven't seen in every PDP/LCD panel I've looked at. Final settings will improve things further. The HD tuner/reception is also very good. I haven't come across signal strength in the menus yet (maybe service menus?) to confirm.

The 50" PDP Pana/Fuji & Pioneer looked better in store. The 46" Sony/Samsung LCD looked great with 1080p, but backlight & typical large panel LCD issues kept me from buying. Also, I'm not a gamer these days, nor will I connect a HTPC for 1:1 pixel mapping. I was very tempted by the 50" Pana due to <$4k price & 1366x768 square pixels/correct AR, but thought I'd grab the 42" & put the ~$1300 difference towards replacement tech in 3-5yrs. In 12 months, better 1080p PDP/LCD panels will be released anyway... :P

Edit: Correction. Addendum.

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Still on run in settings but have seen no sign of the snake......

Don't have Harry Potter GOF, any other suggestions?

Build date Nov 2006 for the X600A.

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Guest spoleweski
Bothered me to no end, replaced set within about 7 days. You will see it everywhere now, adverts, tv shows...

so your set was fixed? or is it a complete new one? do you know what the cause of the problem was?

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Great! So it sounds like the snakes are in Australia too - better call Samuel Jackson...

Still no word on when mine will arrive but will test as soon as I get it...

Peter VFR - either rent Hazza Potter or have also heard of testing on West Wing (ABC) and Panic Room.

I fired off an email to Panasonic Australia with the link to both UK and US forums asking whether they were aware of the issue and whether it had been showing up in Australian sets... no word yet...

I have a feeling it will p*ss me off if I have it so might need to consider the 50"

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I guess the question now is whether all Pana 42 inch sets have the snake, whether it is limited to particular batches or whether it is just hit and miss. It sounds like a hardware issue so it seems a bit odd that some would have it and others wouldn't unless there has been a change in the hardware specs.

Can anyone definitively say their set doesn't have the problem?

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so your set was fixed? or is it a complete new one? do you know what the cause of the problem was?

No I had the set replaced and took another one home with the exact same problem so I got my money back. I used Pirates of the Carribean as my test disc, the raid on the governors home at the start showed the fault well.

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OK - getting my set on Wednesday next week - will be explaining to the sales guy that I plan to check for this straight away and return if there is a prob - will point him to these threads too.

In the meantime can everyone who owns one run and post the "snake test" images? - even if you run them and find no snakes please post so we get some indication of "snake" to "no snake" ratios...

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is this purple snake the reason why the PV60A & PX600A's are going for sooo cheap??, i've not yet noticed it on my set yet, i've had it for 2 weeks with all the setting set at about 40-50%.

my build date is Oct 2006, made in Japan.

i haven't tested it with any of the above mentioned movies yet, but probably will check it this weekend. if it only happens in certain circumstances (extremely dark or extremely light scenes etc)then i can live with it, but if it happens on everything, then i'm going take it back for a refund and get the Hitachi, which was my second choice!!!

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I was aware of the issue but had not seen it on my PV60A. Last night I explicitly looked for it in Harry Potter at 5min10sec and saw it. I had previously watched this movie and did not notice it - in fact last night, after I saw it and after pausing it, I then watched the scene again and hardly noticed it, as it is only on screen for a very short time period.

I did not notice the snake on anything else we watched last night either.

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Guest spoleweski
A couple of good links for a DVD test reel so we can standardise the test for these sets... It shows the snakes well based on what I've seen on the UK site... Can we run and post some pics on various settings?

http://www.4shared.com/file/8670152/eec5b1...esnaketest.html

http://www.4shared.com/file/8718626/220efb...aketest_v2.html

Are we meant to be seeing snakes around which area? the contours of the circles?

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Yep - you will get purple rings...

Take a look in here for some examples of what the test pattern looks like with snakes;

http://www.avforums.com/forums/showthread....ighlight=snakes

I tested my panel (42pv60a. Bought in end of Nov. Made in Japan) with the Harry Potter scene. I would say there is none (or almost none) on mine. Hardly visible if there is a very very little sign. Definitely not as obvious as the pictures shown in the thread.

Viewing the scene and the pictures reminds of the "microblocking" issue of some dvd players (EG my Panasonic s97) which has been heavily discussed in other threads. Basically you would see some pink tint/digital noise in some dark scenes. The best place to check this is the "Superman Return" DVD where the pink tint was all over every dark scenes on my TV (I suggest you watch the whole movie then single out all the dark scenes). EG Starting from Chapter 20. Around 1:10:58. The superman and the girl flying on the sky. Plenty of dark/gray clouds on the sky. I used to get very obvious pink tint on the clouds. After reading a thread for s-97, I applied the lastest firmware 366. The pink tint are all gone. So I always thought this is more of a problem for the DVD player than the TV panel.

My theory is that it is a result of inaccurate digital signal processing (or you can call a bug) which can be fixed by applying correct fix (better algorithm). Some TV panels have worse built-in processing engine than others and are prone to have the issue. The fix can be done on your DVD player (by applying firmware). I am not aware if you can apply firmware on the TV panel. But I am sure once manufacturers are aware of the issue, they will fix in the next batch. So whether or not you will have the problem really depends on the combination of your particular DVD player and your TV panel.

I.E if your TV has better/improved built-in digital process (EG 50" panasonic as claimed in the thread or the problematic 42" applied with latest fix from manufacturer) , you are less likely to see the pink tint/snake on your TV regardless of what DVD players you use. Or if your dvd players have better digital process (Some high-end model like pioneer 989 or panasonic S-97 with lastest firmware applied for example), you are also less likely to see the pink tint/snake on your TV regardless of the quality of the TV built-in digital processing engine.

Both scenarios I believe it would be difficult to claim hardware faults on the TV panel.

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Guest spoleweski

i just looked at my set (got it this morning) watched the snake test dvd and its all green, green i tell you! not one purple snake. its awesome! i got mine from DJ's castle hill

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I used Pirates of the Carribean as my test disc, the raid on the governors home at the start showed the fault well.

Just watched this again and saw no sign of the purple snake.

However, I am still using the running in settings and my just be missing it...... :blink:

(Nov build X600A)

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Just watched this again and saw no sign of the purple snake.

However, I am still using the running in settings and my just be missing it...... :blink:

(Nov build X600A)

can you post the time, chapter etc for these scene from pirates

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I'm a bit confused why people are calling this the 'purple snake' problem. From what I can see it's just a case of False Contouring/Color Banding from insufficient color depth. Same thing you can see on PC games for example if you run them with high level texture compression in 16-bit color depth (tends towards visible purplish patches).

Note that I have the previous gen 42" PV500A and have never had this problem, although I wonder if you guys have the 'HD Color Matrix' setting available to you (and enabled) in your display settings? I found this helps reduce any potential color banding.

If the guys at the AVS forums report it though, it sounds like a problem with the digital processor and not something straightforward.

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