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Ever have a D’oh! D’oh! D’oh! moment?

September 26th, 2011 10 comments

D’oh! Moments happen. I had one last night. I had prepped everything for the VAT tilt ( see Sept. posts ) and decided, that I should have the projector image size problem taken care of before I attempt to mount the assembly on the frame. I meticulously started to disassemble the projector and got to the bottom plastic, removed the light tunnel and D’oh! I found the way of taking off the lens assembly and adjusting for focus was not the one I thought it was. It Was A Lot Simpler ( 5 screws and 3 bolts). See below:

A little twist on the lens protector and it comes off.

Uuuuu Aaaaaa! Never mind the feet-once you take the cover off and protector there are only 2 screws ( and 2 clips ) holding the front panel.

And there it is! only 3 screws hold the lens to the light tunnel. I had it completely torn down just to discover this.

The projector ( a Dell 5100MP ) is extremely easy to adjust for focal distance. All I need now is a 22mm high x 70.5mm ring to use as a spacer and I have a perfect 60mmX80mm picture with no aberration and no distortion.

I also removed the focus ring limiting screw ( not the focal distance limiting ). To do that, you have to line up the slot with the window in the focal distance ring and then line up the focus limiting screw. Now I can move the Lens assembly in and out of the light tunnel to adjust the size of the image, move the focal distance ring and focus the image more freely.  See below:

Hope all is going to plan on your build and I wish you to have less D’oh! moments.

 

P.S.  As ChrisO’s comments  defined the procedure:

1) Flip the projector upside down
2) There are 6 screws: 1 in each corner, one in the middle back, and one in the center. Some of the holes are pretty deep, and all the screws are phillips head.
3) Three of the plugs on the back have standoffs for screwing the connectors to the projector. I removed all of these.
4) Flip the projector right side up.
5) Gently remove the top. It is connected to the main board by a ribboon cable so be careful.
6) Take off the lens cap. now hold the focus ring and twist it so that it goes back towards the projector body. If you apply a little extra torque at the end it will pop off easily.
7) To remove the front plate, there are 2 screws (silver colored) near the bottom to take out. You should be able to unclip the plate and take it off easily after that.

8) Once the front plate is off, remove the zoom tab lever thing. This is the tab that sticks out of the slot above the lens when the projector is fully together. It’s just 2 little silver colored screws that are positioned with their axes radial to the lens assembly. Then you can slip the tab thing out. For this step and the following steps you’ll need a small philips screw driver, like a jewelers screw driver.

9) The lens assembly is attached to the light tube with 3 black screws. They are on an outer flange and their axes are parallel to to the lens assembly center axis. They aren’t evenly spaced around the lens; two are near the top and one is to the left.
10) The lens assembly should pull straight out easily.
11) You might have noticed the flange that held the 3 little black screws has a notch that is about 1/3 of the circumference. Set the lens assembly on the table so that notch is facing upwards.
12) Now twist the zoom so that it s almost all the way extended. There is a small, U-shaped notch in the black ring just in front of the flange with the big notch. The zoom limit screw is about a 1/4″ from the end of its travel on miune and the U-notch is pretty much centered in the big notch on the flange.
13) Twist the zoom and you should see a tiny silver screw head pass by under the U-shaped notch. That is the limit screw you want to remove. It was difcult for me to get out so I had someon hold the lens assembly for me. Then I held the jewelers screw driver down in the screw firmly with one hand and used a pair of pliers to torque the screw driver. After a few turns the screw was loose enough for me to lose the pliers and just use the screw driver.
14) … The next step is to lock the focal distance (I think that’s the correct term?).

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