EPSON PowerLine Home Cinema 8100 color convergence problem - AVS Forum
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post #1 of 6 Old 07-06-2014, 02:18 AM - Thread Starter
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EPSON PowerLine Home Cinema 8100 polarizer and color convergence problem

Hello there,

I just got a used EPSON PowerLine HC 8100 projector which appears to have some sort of color convergence problem (blue and red colors seem to be perfectly aligned and the green color is misaligned.

Some Epson projectors tend to have this "advanced" or "extended" menu where you can find "LCD alignment" settings. Some other projectors have this menu hidden, but can be shown if you enter the "DIP switch" settings menu and change bit 5 of the DIP switch 6 from 0 to 1.
I tried that procedure and successfully changed this bit, restarted the projector, but the "advanced" or "extended" menu item was still missing.
Perhaps anyone knows if this projector has this option hidden somewhere or not? Maybe some other bit has to be rised?

Here is a photo of how the picture looks like. It's not of a very good quality though.


You can see, that I also have some green glow, mostly in the middle area of the picture. I am guessing it's a burned polarizer for the green color. There are probably two polarizer (one is before LCD and the other is between LCD and a prism). I am not sure which one would cause such effect. I actually took out the first polarizer and it looks perfect... no noticable damage.

I wonder if a burnt polarizer could also be a cause for the misalignment of the green pixels.

Thanks for any tips in advance.
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Last edited by grpo; 07-15-2014 at 10:29 AM.
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post #2 of 6 Old 07-14-2014, 11:56 PM - Thread Starter
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[please use Chrome, because Firefox does not show images in the post]
I am answering my own thread. Because I did not receive any answer I decided to try to replace the burnt polarizer myself. And actually succeed.

Here is the procedure:

To take the upper white colored cover off the projector, you have to unscrew 6 screws and 5 additional screws that hold the side silver colored covers. All of these screws are on the bottom of the projector and they are all of same type (don't worry, just get them out).
When the screws are out, turn around the projector and take off the side silver covers (be careful: left cover has buttons on it, so it is connected to the projector with a flat cable).
Slightly pull up the projector upper cover and carefully disconnect its flat cable from the main circuit board. Now you can take off the cover.
Now you can also disconnect the flat cable of the left silver cover with buttons.

The projector is open. You have to take off the circuit board to get to the optic engine and the prism-lcd-block.
The following picture depicts the connectors you have to disconnect (red arrows) and the screws that have to be put out (blue arrows).
Be carefull with the connectors (especially with the three flat lcd connectors).



Now that the board is out, you can see the optic engine, which you also have to take out so you can take out the prism block.
The optic engine is held in place by only 4 screws (see the following picture).
First take out the lamp by undoing its two screws (blue arrows) and then undo the 4 screws (red arrows).



Now that you have the optic engine out, you can carefully turn it around and find one screw below the prism block. If you undo that one, the prism-lcd-block falls out (be careful not to let it fall down, because it can get damaged).
Here is the prism block with lcd displays on it:



When I looked through the prism block, I could see the burnt polarizer, which was unfortunately deep inside the block (just next to the prism).



But because I was very optimistic and I really wanted to have a good projector again I took a deep look at it and then decided to get the poor burnt thing out

You cannot get this piece of glass out by undoing screws, because it is glued into the assembly. But if you take the two plastic covers off, you can see how it is glued onto the prism block assembly at four spots (4 drops of black glue). All you can do now is to take a scalpel and cut this glue off so you can take the filter out. Be careful to remember how it was turned.
When I got mine out, it looked like this:



The damage is very obvious (it is very rough in the middle, and a circle can be seen around it - like a bubble).
This was the main cause for the distorted picture.

There are few peaces of glass in the block:
- The first is an "incidence" polarizing filter, but it is not mounted onto the prism block, but on the optic engine assembly.
- LCD screen (mounted with two screws)
- First unknown filter (mounted with two screws)
- Second unknown filter (mounted with a clip)
- "projection" polarizer (mounted with a glue and burnt in my case)

You dont have to disassemble any of them to remove the bottom "projection" polarizer, because it's not any easier to remove it if you remove the lcd and the following two glass filters. Surely enough I didn't know that so I removed all of them and then I had to allign the lcd screen...

I had an old non-working LCD monitor in a garage, so I took it apart and took out the LCD screen. Then I delaminated it (by that I mean pulling apart the two thin glasses that the LCD is made of). The outer panel of these two (the one that was at the outside of the LCD monitor) is just perfect for the job, because the glass is as thick as the glass of the burnt polarizer and it also has a polarizing filter already glued onto it. You just have to scratch off the black surface on the other side (these are very tiny red/green/blue filters for each pixel, but we dont need this surface).
You just have to cut out a peace of glass of the same dimensions as of the burnt polarizer. VERY IMPORTANT: the angle has to be correct. When you put the new and the old polarizer together and allign them, there should be no light blockage (all the light that goes through the first, should go through the second, and when one of them is turned for 90 degrees, almost no light should go through). This is very important, because otherwise some light will always get through and you will have slightly green screen instead of black.
Cutting the glass was a pain in the ass for me. These diamond glass cutters just didn't work for me. So in the end I decided to brake the big lcd screen glass in pieces and take a small, but big enough piece and grinded the square filter out of it. Prior to that I glued some tape on both surfaces so that the glassy dust wouldn't scratch it.
When you have a new polarizing filter glass cut out of the old LCD monitor, you can glue it into the place of the old one (I used a two component glue called "liquid metal", which won't get damaged by the heat). And one more thing: you have to clean the remains of the glue off the prism block assembly (the new filter has to lie perfectly flat, otherwise you will have a focus problem) (i.e.: left side of the screen will be in focus, while the right side will be slightly out).
Clear the oil and dirt from the polarizer before gluing... (you probably touched it with your fingers and left some oil on it)
Clear the glasses of the prism block (4 lcds and the "light outlet" glass) before mounting the block back into the optic engine. Mount everything back together...

LCD allignment (green):

As I said I removed the LCD screen so I had to alling it after replacing the polarizer. It is not too complicated... you just put the optic engine to the table and turn off all the lights in the room. You have to get a pocket torch (flashlight) (the brighter, the better) and direct it into place where the projectors lamp would be normally placed. On the wall there should be white image with some green and pink lines along the sides (in case the green lcd is misalligned). Set the focus of the projector so that these lines are sharp.
Now you just take the prism block out, unscrew the two lcd screws (I mean just a bit, don't take them out) and move the lcd to the direction where you saw a green line. For example: if the green line was at the top of the projected image, you should put the lcd up a bit (but REALLY just a bit!) Put the prism block back in and see if it makes and difference. Repeat the procedure as long as the image is not pure white (meaning there are no green or pink lines anywhere on the projected screen). The problem is that you have to find a method for making really small moves of the LCD - maybe tapping it with a screwdriver or something. With a bit of luck and some patience it can be done pretty well!

I had some doubt regarding my new cut-out filter as it is not made for high temperatures, but we will see... so far I watched like two or three movies with it and I can see no difference in picture (it is still clear and non-distorted). If this filter also gets burnt, I will probably order one from polarization.com:
http://www.polarization.com/polarsho...d33dbea8e08ed1
This filter is high temperature resistant and should be ok for the job, but as for now it is not needed

I hope I gave you an idea.
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Last edited by grpo; 07-15-2014 at 10:51 AM.
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post #3 of 6 Old 07-30-2014, 04:07 PM
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Hi grpo,

First off, many, many, MANY thanks for digging into this!! I'm pretty blown away that someone figured out a fix for this.

I purchased a used 8100 about 2 years ago that supposedly only had ~400 hours on it. Bulb blew another 100 hours later, but I was able to get Epson to comp a new one. I just got up to around ~300 hours on this new bulb. So a total of around ~800 hours on the projector.

Much to my dismay, I turned it on a few weeks ago and had the EXACT same green blurry spot in the middle of the screen. I tried the "blowing compressed air around the LCD trick" that the "dust blob" guys have and it didn't fix anything. Instead it appears that I have the exact same problem as you.

I've read your post about 6 times now, and think I have a handle on how to do this myself. As you mention though, the thing that is the biggest concern is getting a new piece of glass. I don't know much at all about this type of glass, but did you see if you could have scraped off the burnt polarizer with a razor blade? A window cleaning trick I use with sticky things like stickers is a razor blade with tons of Windex as a lubricant. If you are careful you can get stuff off with no scratches. I have a feeling this wouldn't work, but I was curious your thoughts about it. The reason I ask was that I was going to purchase the polarizing film you link to and give this repair a shot. Again, my only concern is getting new glass.

Anyone else out there have any suggestions for getting glass squares this shape and thickness?

And finally, again, thank you grpo. As much as I like the picture from this projector, the reliability has been horrible. Hopefully I can fix this and put it behind me...
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post #4 of 6 Old 07-30-2014, 07:09 PM
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So I decided I didn't have much to loose, so I tried to answer some of my own questions. Into the beast we go!



As expected, I have the exact same problem as grpo. Green polarizer was burned right in the middle. Blue and Red look fine.

It seems like if you want new base glass (without polarizer), one guy on the forums found this: http://www.tedpella.com/histo_html/q...cro-slides.htm

The even better news is that I was able to carefully scrape the old polarizer off.



It took a while and you have to be careful not to slice the crap out of your finger, but it did work. It also took a little while to polish it to get all the residue off, but in the end the glass is clear and ready for some new polarizer. Also for reference, if you do want to order new glass, the dimensions of the glass are 24mm x 20mm

It is also a pain to clean the 4 dots of glue off the prism block.

Next step, order some sheet from these guys: http://www.polarization.com/polarsho...d33dbea8e08ed1

The only issue now is how to align the new polarized sticker. Although it is mangled, I hope I can use the old polarized sticker as I did try and pay attention to its orientation before scraping it off.

Fingers crossed...
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post #5 of 6 Old 07-31-2014, 12:34 AM - Thread Starter
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Hey, I am glad my post encouraged you to do the repair yourself.
When you get the filter you ordered, just put the old one on the new one and place a bright light in front of them. Then take a look at the light through the filters and rotate the old filter until you see the light as bright as possible (this is a pretty important step, so make sure you fine-adjust it!) Now you can cut out the new polarizer piece and glue it to the old glass.
I think that this new polarizer is coated with glue so I hope that this glue is of good quality. Make sure you leave no air bubbles, dust or fingerprint residues on the glass.
Good luck!
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post #6 of 6 Old 08-03-2014, 09:37 PM
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Well, the results are in, and I was about 90% successful. I put it all back together and cranked it up and sure enough the green blob in the middle is gone!! Hooray! It was super clear, the colors all looked right and everything was totally watchable again!! YES!

I watched a few videos though, and when it faded to black I was like, wait a minute, did I see a dot? Sure enough, it wasn't perfect. Either there was dust that I didn't get out, or some scratch that I got on the polarizer. There are a few small light blue and green dots on a pure black screen. The good news is that you can't tell during 99% of the time. (unlike the green blob that was noticeable all the time)

Either way, this wasn't a super easy repair. Some comments for those that want to tackle this themselves:

1. The high temp polarizer from polarization.com seems to work so far. (BTW, big props to those guys for getting out a sheet very quickly! Two day priority mail got it to my house on Sat just in time to tackle this on the weekend. Thanks!) We shall see how it holds up. The issue is that it is hard as hell to get it to glue to the glass without any tiny bubbles. I had to go through 5 different squares before I got one that looked good enough to not have any bubbles. The sheet they give you is big, so no worries about going through a lot. I got to be a pro at using the razor blade to carefully cut the old film off.

2. That being said, I have a feeling that I might have made some micro scratches in the glass during all this work. I tried to make the working area as clean as possible and used compressed air to blow down everything to keep dust out. Nevertheless, this was by no means a "clean room." Thus the small dots on a black screen.

3. All I can say is breath deep and keep a cool head when applying the polarizing film, and then positioning the glass slide, and then trying to glue it all without scratching the polarizer. I used JB Weld which is rated for 500 degF, so I think I'm good there. However, I glued it in late last night only to find this morning that I had scratched the polarizer really bad. So I had to cut the glue off again, and start all over. This time I thought it all looked pretty good before putting it all back together again. I thought I had seen some small scratches, but it was hard to tell. In either case, just be as clean and careful as you can.

4. Even though I banged and beat the projector up, it all went back together fine and seems to be A-ok. The thing I was most worried about is what grpo went through with having to re-align the LCD screens. I did as he suggested and didn't dare touch the screws on the LCD and it all looks fine. No adjustment needed.

If it stays like it is now, it is for sure good enough to last until the next best thing rolls along. I really didn't want to buy a new 8350 seeing as it is so late in the model cycle. I have a feeling it is going to get replaced any time now!

Anyway, I think that is it. AGAIN, huge thanks to grpo. Without this guide I wouldn't have dared to try this!
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