Flextone's Cleaning and Re-Adjusting the TDC Project-or-View
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ANOTHER TREATISE ON DISASSEMBLING, CLEANING, AND RE-ADJUSTING MOST MECHANISMS ON THE TDC PROJECT-OR-VIEW:
After finishing, after almost 6 hours, I disassembled the POV completely, cleaned all surfaces and fixed an inoperative stereo separation mechanism . The POV performs beautifully and is very bright and contrast. If I were to do it again, it would now take me perhaps 2-3 hours, maybe less. Harry Poster discussed doing this at one time, but it's been awhile since this subject has been re- visited. I just wanted to drop some hints for anyone doing the same for their POV.
1. REMOVING THE CASE HOUSING, FAN, AND BULB HOUSING: Turn the POV down on its face, while pushing the screen-like panel into the projector position, so it won't fall on its on when turning the POV over. I am including how to remove the plastic housing, which is by unscrewing the two thumbscrews under sides of the housing and gently pulling the two halves of the plastic housing apart. And I am including the removal of all the screws that are in two rows, on both sides of the underneath, including a third bottom row, plus the two larger screws which hold the fan in place. CAUTION: The two screws holding the fan, when removed will leave the fan hanging from its power wires, which may or may not be frayed or delicate. Just be prepared to grasp it as soon as you remove the bottom plate and gently pull it from the rubber holder where the fan shaft connects to the main housing.
2. REMOVING THE POLARIZING SCREENS: These are held in place by a long, horizontal pin (it looks like a metal hanger wire) which can be pulled out sideways by grasping the only thing on the pin that looks like a handle. Pull the pin straight out from the side where the handle thing is. If you are looking at the back of the fan/bulb unit, the handle thing is on the right side. When the pin is removed, you can lift the polarizers straight up and out. You might have to pry the sides of the frame out slightly to get the polarizers out. Not sure if this is important, but you might want to mark or place a mark on the front and top side of the screen prior to or when removing it so that it is replaced in the same orientation.
3. REMOVING THE LENS SEPARATION MECHANISM (aka the interocular adjustment as on a stereo viewer). To remove the lens barrels from bottom/front of the POV, first unscrew the tiny screw that holds the focusing knob. Next, remove the E-ring from the shaft. Then, screw in the knob's shaft until it clears front of the POV. Use a jeweler's screwdriver to unscrew 4 screws underneath the lens barrel housing, 2 of which are hiding under a spring on each side. Gently wiggle out the barrel lens housing until it clears the POV housing/frame.
4. MARKING THE LENSES TO AVOID RE-FOCUSING LATER: Prior to unscrewing the achromats from the focusing lenses, use a white pencil or crayon and make a straight line mark across the lens barrel to the bakelite lens holder. I used my wife's white finger nail pencil. The note how far in the lens barrel is in relation to the backlight lens holder (The lens holders are those 2x2 square that are surrounded by the two springs and belts that control the stereo lens separation housing.) Marking the position of the lens barrels will ensure that the focus will not need to be re-adjusted when you re-assembly the lens barrel housing. If you fail to do this, you will be in a world of hurt attempting to re-focus the lens barrels because the fan will be in the way and the heat of the lamps will be hot. I heard you can use a flashlight in a darkened room with the fan housing attached to re- focus. In my case, it was the stereo lens separation that was frozen tight.
5. ADJUSTING THE LENS SEPARATION: Regarding the lens separation mechanism (aka the interocular adjustment as on a stereo viewer), which is controlled by the top knob on front, even with fresh grease the square lens barrel holders were too stiff for the dual springs to close in the lenses. I think the reason for that is that bakelite, which age, is not as stable a chemical mixture as one would think. Bakelite, like old plastic ophthalmic eyeglass frames, are in chemical imbalance. The correct definition is somewhat the opposite of homeostasis. With age, bakelite appears to expand/contract depending on the environment of where it is usually stored. Therefore, I had to file down the sides to make the square pieces slide easily across the steel plate in which they reside. Not having a metal or wood file handy, I simply walked outside and rubbed the sides of the bakelite squares on my cement sidewalk, while making sure I didn't grind it too much. Now, the stereo lens separator contraption is very smooth. Warning-Grinding too much will cause the squares to have too much play and the springs will not be able to overcome/over compensate for the slippage.
6. CLEANING: You will now have complete access to adjust and clean the barrel lens achromats, focusing mechanism, mono-lens mechanism which is used for viewing non-stereo slides, and of course, the lens separation mechanism which is used to fuse the slide images for the viewer and projector so that you can get a stereo effect (aka the interocular adjustment as on a stereo viewer).
You might want to use canned air (used for computers) or a camel's hair brush or clean small paint brush to clean out the POV, but avoid blowing or wiping any dust or other dirt against the lenses, because there is a chance of scratching, although glass lenses generally are scratch resistant to common dust and soft debris.
While you now have access to everything, remove all the large magnifying lenses in front of the projection lamps and clean them with a liquid lens cleaner, which is available at any camera shop or Best Buy. Basically, it is denatured alcohol, UNLIKE the rubbing alcohol used for removing nail polish or for antiseptic purposes. Rubbing alcohol will leave a gummy residue behind, which is not desired. Use a clean soft cloth or lens tissue for the lenses, even the barrel lenses, which you all probably already know how to do. On each side of the fan transformer, is a bottle-cap looking piece where the fan shaft goes through. You will notice a small hole on each piece. In this little hole, there is packing material that needs to have a drop of oil in order to be moist. The packing material holds the drop of oil to lubricate the fan shaft, which in turn, keeps the fan quiet. I used 3in1 oil, but most any low-viscous( light, not heavy and thick) lubricating oil will work.
7. RE-ASSEMBLING: This should be self-explanatory. It is basically reversing the above steps. Try to avoid forcing anything. If it came apart easily, it will go back the same. Just remember to guide the fan's protruding shaft back into the rubber that it attached to the main housing. And remember my note on placing the polarizer in the same orientation as it was removed. Good Luck!
Flextone