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14 January 2013
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Focus problem on LCD EPSON

Certainly those who fiddle with the video projection will have heard of the problems focus of Epson LCD. On the other hand those who’re owners will have already experienced.

The Focus problem of Epson regards almost all of the models the last 5 years. Of the 3000-TW5500 until the most recent TW9000-5900.

Here we introduce the problem and we’ll talk about the possible causes of the cause.

The problem facing these projectors is that they don’t make the right focus on the entire length of the screen. I.e. If we correct a focus on image, or another will be slightly out of focus to and vice versa.

See below and you’ll understand …

There is this case to defocus is done in corners and not across the side of the image. If the above image try to correct the focus left with the corresponding ring of the lens then will spoil the right side of the image.

This problem has nothing to do with the lens, its construction or its placement on optical projector.

This problem has to do with the alignment of the panels and the Prism behind the lens.

Unfortunately the Epson doesn’t have high standards of other companies to build quality, something which we have seen several times opening the headlights, either for repair or cleaning.

Bolts directly onto plastic (without metallic threads), complete lack of grounding in wiring, plastic materials with huge tolerances and slight resistance to temperatures, etc.

In an optical LCD, very important work, before the spotlight pass the exit door of the company, is the alignment of three panels and the Prism.

If all three panels are not properly aligned with each other then you have convergence problem

And if the light is not aligned then encounter the problem of focus mentioned earlier (and clearly affects negatively the convergence).

Let’s see some pictures to understand the problem.

This is the optical engine of Epson in a TW3200

We’ve already removed the lens with the lens shift

And here we see the front side of the Prism just before the light come on lens … There lies the root of all evil ….

Let’s observe and from the bottom …

What I perceive is that the light together with the Panel is screwed onto the metal frame with one screw! Unbelievable yet true. There are also such as perceiving, two black lugs snap on metal base, without of course fit perfectly, leaving the Prism to rotate slightly right or left if you loosen the screw.

This “bad” way to support the Prism is due essentially to the bad Visual focus. If we take even a little light from the one and only place that must be located, then you get a magnificent out of focus image on one side of our frame. As you understand, with only one screw holding the light, with very poor quality “elastic” basis of Prism is extremely easy to slightly rotate the light either in the Assembly or during transport of the projector to the selling points, causing it to end up with problem focus on unlucky owner.

Here to say that on some other models, the way support change, other manufacturing and Assembly quality remains the same, exactly the same display problems.

Finally to say that the problem is fixed (as was done on the projector that you see in the photos) with fine tuning of the Prism and strong bonding of the metal base to prevent rotation in the future, either by transfer or shake overworked by the high operating temperatures of the optic (due of course bulb).

2 Comments

  1. Jörg Knochen says:

    Hi! But exactly HOW do you fine tune the prism? is there a guide anywhere can you give me advice? I have exactly this problem.

  2. Tsolas Nikos says:

    there is no guide. You just have to find the right angle between prism and lens.

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