Screen Restack and Electrical Focus guide, with photos (1 Viewer)

[Jeff Peake]

I have just done a screen-restack and electrical focus on my Pioneer 643. I included photos, to guide anyone else who may want to do this to thier sets.
The screen restack makes a world of difference.
http://www.jeffpeake.com/theater/restack.html
Jeff

 

[Jeff D.]

While a restack improves things, I still firmly believe that removal of the protective screen is better than restacking. Adding any useless medium into the optical path is NG in terms of image quality.
It takes a bit more work, as one must usually build shims to make up for the lost thickness of the protective screen, and a refocusing will be in order too. But the results are more than worth it.
/Jeff

 

[brucek]

The screen reshuffle is a real improvement, but I agree with Jeff K that completely removing it improves the picture even more.

When the screen is on the inside, halos become more of a problem because that nasty glare screen now reflects the light around more inside the set and creates a halo effect.

On the other hand, the screen on the inside tends to make the face of the set stiffer and less prone to damage from little fingers. Once that plastic screen is gone, the lenticular and frensel don't provide much support.

The shims problem can be taken care of easily with black strip foam insulation from Home Depot.

brucek

 

[Jeff D.]

Two tips to help with removal of the protective screen.
1. You'll have to use some sort of shim to make up for the lost thickness of the protective shield. First, use something hard - such as wood - for your shims. Don't use something soft like weatherstripping. Also, instead of making the shims the same thickness as the shield, make them just slightly larger and place them at the pressure points in the frame (ie. at each position where you inset a screw into the bracket).
2. When you have the screen stack laying on the floor, ready to be reclamped after removing the shield, place a few magazines underneath the screen. This will serve to prevent the screen stack from sagging and will make it even stiffer.
Using these two methods, I have an extremely rigid screen stack, consisting of just the lenticular and fresnel. It is more rigid than its original factory design (with the shield). It is also perfectly flat, helping focus across the entire screen area.
/Jeff

 

[brucek]

Jeff K,
I wonder why you don't like the weatherstrip method. Did you find a problem with it?
I felt the wood method that requires first painting the strip black and then gluing onto the brackets a bit of a pain.
The roll of black weather strip come the correct width of 3/8" and have a nice self stick on one side for easy application. The other side seems to provide a nice grip because of the foam surface. The 3/16" thickness compensates nicely for the loss of thickness of the plastic screen saver.
I used this on my set and it seemed to work very well. Why don't you recommend this method?
brucek

 

[Jeff D.]

Bruce;
Weatherstripping is too soft, IMHO. Remember, you're replacing a piece of plastic that, by comparison, is very hard. Weatherstripping leaves too much 'give' in the resulting stack.
On my second go I used a much harder material and it worked like a charm. I have achieved a very rigid stack - more rigid than it came from the factory.
I guess I won't argue - if weatherstripping has worked for people than that is fine. It didn't come up to spec for me though, so I found something else.
/Jeff