The Align-O-Tron

After trying to use the "string" method (several times) to align my lamphouse, I decided that there must be an easier, faster, more accurate way. The idea of using a laser light source came to mind. Light beams do not suffer the inaccuracies of strings or human misperceptions. They can't sag or be bent or deflected. The user gets "the truth" quickly.

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The Align-O-Tron is inserted into the projection lens holder facing toward the lamphouse and turned on, after donning eye protection.

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Alignment of the lens holder to the center of the aperture plate can be checked to make sure the lens holder assembly is in the correct position.

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Nuts. I thought it was aligned better than that. A quick look tells me that I'm above center (notice that the laser is hitting below the end of the bulb, on the clamp).

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After the bulb is carefully removed, the target tool is placed in the reflector. Each step in the pyramid has been machined to fit various reflectors.

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After some adjustment to the lamphouse, the reflector is brought into the proper position.

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Ok, I've got the lamphouse in line with the lens, but how do I know where the reflector is aimed?
Using a technique based loosely on a method used by astronomers, a simple mirror is held tightly against the opening in the reflector. The laser will be reflected back and show where the reflector is aimed.
The mirror does not have to be a first surface mirror! Reports from the field show that any flat reflecting or partially reflecting surface may be used. One user used a piece of broken port glass another used the jewel case of of a CD. As long as the surface is flat and will reflect a percentage of the laser light it will work. I used a dime store mirror with the plastic frame removed so that it would fit flatly on the back of the reflector.

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I can't believe how far this thing is off ! Notice the reflected laser at the 4 o'clock position. No wonder I was getting hot spots.

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The reflector is "aimed" using the adjusting screws so that the laser is reflected back to the point of origin.
The bulb is reinstalled. Note now that the laser hits dead center of the axis of the bulb. The elevation of the bulb was 1/2" off. The lamphouse was skewed to the side and the reflector was off by a mile. It is now perfectly aligned and can deliver all the light it was designed to deliver. The difference is quite noticeable on the screen. No more streaks or hot spots. Just a nice flat light across the screen. The light output has increased to the point where I am now considering lowering the output from the rectifier !

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Our Hero!

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Greg Mueller