Panasonic PT-AT5000 "shadow" in black screen - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 21 Old 05-11-2019, 12:03 PM - Thread Starter
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Panasonic PT-AT5000 "shadow" in black screen

I have an older PT-AT5000 projector.
The colors look fine to me (white, red, blue, green), but in very dark scenes or just black, there's a darker triangle visible in the center.


My camera isn't able to capture it (it's only visible if the room is completely dark).
When i hold a white paper close to the lense, you can clearly see the shape). (It looks blue, but this is actually black on the screen.) When i do the same with colors or white, all seems fine.



Anyone an idea what this can be?
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post #2 of 21 Old 05-12-2019, 08:20 PM
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Quote:
Originally Posted by catfishjvl View Post
I have an older PT-AT5000 projector.
The colors look fine to me (white, red, blue, green), but in very dark scenes or just black, there's a darker triangle visible in the center.


My camera isn't able to capture it (it's only visible if the room is completely dark).
When i hold a white paper close to the lense, you can clearly see the shape). (It looks blue, but this is actually black on the screen.) When i do the same with colors or white, all seems fine.



Anyone an idea what this can be?
Hi,

I suspect you got either a crack on an inner glass or some particule in front of it.
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post #3 of 21 Old 05-13-2019, 07:24 AM
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If its dust you usually can adjust the focus and make the foreign object sharper. Dust in LCD's is very common.

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post #4 of 21 Old 05-13-2019, 09:15 AM
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Originally Posted by rekbones View Post
If its dust you usually can adjust the focus and make the foreign object sharper. Dust in LCD's is very common.


I’m thinking it may be something larger than dust, like some fiber.


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post #5 of 21 Old 05-13-2019, 10:21 AM - Thread Starter
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Originally Posted by descalabro View Post
I’m thinking it may be something larger than dust, like some fiber.


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Thank for the reply.
Can i "investigate" this myself or should i search professional help?


I will try to use the focus to make a sharper picture. It's just so inconvenient it's only visible in the dark.
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post #6 of 21 Old 05-13-2019, 08:37 PM
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Quote:
Originally Posted by catfishjvl View Post
Thank for the reply.
Can i "investigate" this myself or should i search professional help?


I will try to use the focus to make a sharper picture. It's just so inconvenient it's only visible in the dark.
If you are skilled with your hands and have some tools, you can try looking into it yourself. Otherwise, it shouldn't be too expensive to get a technician to do it.

The reason why it's only visible in the dark is because otherwise the light masks it.
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post #7 of 21 Old 05-18-2019, 06:18 AM - Thread Starter
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I opened the unit, the lamp looks ok, but i can't remove the A PC board and so couldn't reach the lcd's.
The cables from the lcd's to the A PC board are very thight and i was afraid to break it.
I've disconnected similar cables in pc's and audio sets, very strange.
It does looks like it was repaired before (i'me not the original owner).
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post #8 of 21 Old 05-18-2019, 06:26 AM
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Quote:
Originally Posted by catfishjvl View Post
I opened the unit, the lamp looks ok, but i can't remove the A PC board and so couldn't reach the lcd's.
The cables from the lcd's to the A PC board are very thight and i was afraid to break it.
I've disconnected similar cables in pc's and audio sets, very strange.
It does looks like it was repaired before (i'me not the original owner).


Can’t you at least look at the lenses in front of the lamp? I doubt this has anything to do with the LCD’s, although you might need to disconnect them in order to go further. Isn’t there a tab to flip in order to release the LCD cables?


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post #9 of 21 Old 05-18-2019, 07:01 AM - Thread Starter
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Originally Posted by descalabro View Post
Can’t you at least look at the lenses in front of the lamp? I doubt this has anything to do with the LCD’s, although you might need to disconnect them in order to go further. Isn’t there a tab to flip in order to release the LCD cables?
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Never mind my previous post, it's open


Is it normal al glasses in the corners are mirrors except the one in the top right?

The copper spring is a bit visible when i watch through the left lens.


The lcd's look ok from the outside, now working on the optical unit.
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post #10 of 21 Old 05-18-2019, 07:14 AM - Thread Starter
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I've found nothing. Maybe is was some dust and it's already gone?
Is there a way to do some tests before i assemble it?
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post #11 of 21 Old 05-18-2019, 07:25 AM - Thread Starter
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I think i've found it.
Behind the lcd's there is a plastic and then a lens (or another plastic of very fine glass?).
Behind the blue lcd the plastic is broken and it has a triangular shape like on the screen.
Can i remove the plastic? (I don't know what function it has.)
It has no color, so maybe it's just some sort of protection?
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post #12 of 21 Old 05-18-2019, 01:21 PM - Thread Starter
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The good news: shadow is gone!
The bad news: it's probably not a good idea to remove the lcd's because now they aren't aligned anymore


Can this be done in software of do i have a serious problem?
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post #13 of 21 Old 05-18-2019, 05:22 PM
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Panasonic PT-AT5000 "shadow" in black screen

Quote:
Originally Posted by catfishjvl View Post
The good news: shadow is gone!
The bad news: it's probably not a good idea to remove the lcd's because now they aren't aligned anymore


Can this be done in software of do i have a serious problem?


Sorry to hear that, this is indeed a serious optical problem. Not fixable through software.

The plastic behind the LCDs is also a polarizing filter. The one you removed is likely only a protection. Did you remove it completely? Did you actually separate que LCD panels from the cube they were fixed to? Or did you leave the 3 LCDs together and only pulled out the plastic that had the fissure? Did anything nudge in the process?


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post #14 of 21 Old 05-19-2019, 12:11 AM - Thread Starter
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Originally Posted by descalabro View Post
Sorry to hear that, this is indeed a serious optical problem. Not fixable through software.

The plastic behind the LCDs is also a polarizing filter. The one you removed is likely only a protection. Did you remove it completely? Did you actually separate que LCD panels from the cube they were fixed to? Or did you leave the 3 LCDs together and only pulled out the plastic that had the fissure? Did anything nudge in the process?


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Behind the blue lcd there was only a triangular shaped piece of plastic. If it was a polarizing filter, it was already gone for 60% of the lcd. If i make the image completely blue, it looks ok.
It was only possible to remove the piece by removing the lcd. Stupid me removed the green also to see what's behind it. So now only red is in the original position. (The lcd is fixed by 2 screws. I didn't realize this would be problematic. Some other brands use glue so it seems.)

From wat i've read in the meantime i can try by trial and error...
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post #15 of 21 Old 05-19-2019, 01:35 AM
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Quote:
Originally Posted by catfishjvl View Post
Behind the blue lcd there was only a triangular shaped piece of plastic. If it was a polarizing filter, it was already gone for 60% of the lcd. If i make the image completely blue, it looks ok.
It was only possible to remove the piece by removing the lcd. Stupid me removed the green also to see what's behind it. So now only red is in the original position. (The lcd is fixed by 2 screws. I didn't realize this would be problematic. Some other brands use glue so it seems.)

From wat i've read in the meantime i can try by trial and error...

I know, what you took out was probably a protective skin.
Usually they have glue and screws. I’m surprised you were able to remove tem easily, because usually the screws are very tight.

The blue one seems to be lower than the other two, which makes me wonder if the cube is not itself out of place. Although it has a locking position.

Can you take a photo of this image projected? Make is as straight as you can, and you can even reduce the zoom a little to make sure we can look at the edges of all 3 LCDs.





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post #16 of 21 Old 05-19-2019, 02:19 AM - Thread Starter
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Originally Posted by descalabro View Post
I know, what you took out was probably a protective skin.
Usually they have glue and screws. I’m surprised you were able to remove tem easily, because usually the screws are very tight.

The blue one seems to be lower than the other two, which makes me wonder if the cube is not itself out of place. Although it has a locking position.

Can you take a photo of this image projected? Make is as straight as you can, and you can even reduce the zoom a little to make sure we can look at the edges of all 3 LCDs.





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The screws have a conic head, so i tried to use that to realign the lcd's. It's better than before, but far from ok.
I didn't move the cube as far as i know.


It's a menu (text) and test pattern.
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post #17 of 21 Old 05-19-2019, 05:17 AM
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Originally Posted by catfishjvl View Post
The screws have a conic head, so i tried to use that to realign the lcd's. It's better than before, but far from ok.
I didn't move the cube as far as i know.


It's a menu (text) and test pattern.
Oh, the first time I saw pthe pic in post 11 I tought the cube was in your hand. Nevermind.

I tried earlier to post an image with a good pattern for convergence, but Tapatalk sucks and didn't include the image.

Here it is:


I'm not sure it's worth to continue trying to align this. I mean, you may get extremely lucky and get it right, but you have to consider there are 2 panels with 2.000.000+ pixels each to align with the RED. It's unfortunate that what was only a small defect on dark images has turned into an unwatchable image.
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post #18 of 21 Old 05-19-2019, 03:17 PM - Thread Starter
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Thanks for the image. After i few attempts i fear it is pointless.
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post #19 of 21 Old 05-19-2019, 04:43 PM
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Quote:
Originally Posted by catfishjvl View Post
Thanks for the image. After i few attempts i fear it is pointless.


You can still try to get some money from it by selling the parts. I don’t know about the LCD from which you peeled out the piece of plastic, but the other 2 may be worth about $60 each. Then there’s all the other parts, although I know from my experience that when selling part by part it is nearly impossible to sell all the parts. Anyway, most used part sellers are way overpriced, but they have where to keep the stock and the time to sell it. Otherwise, I would say the whole projector is worth around 250 bucks if sold as is.


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post #20 of 21 Old 05-20-2019, 10:02 AM - Thread Starter
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You can still try to get some money from it by selling the parts. I don’t know about the LCD from which you peeled out the piece of plastic, but the other 2 may be worth about $60 each. Then there’s all the other parts, although I know from my experience that when selling part by part it is nearly impossible to sell all the parts. Anyway, most used part sellers are way overpriced, but they have where to keep the stock and the time to sell it. Otherwise, I would say the whole projector is worth around 250 bucks if sold as is.


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Any idea where i can sell parts like this? Ebay?
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post #21 of 21 Old 05-20-2019, 03:23 PM
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Any idea where i can sell parts like this? Ebay?


Yes, eBay is the best way I know of.


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