Re: Projection experience

[fj834@xxxxxxxxxxxxxxxxxxxxx (Dr. George A. Themelis)]

>I got my lovely TDC-116 projector (and  freebie Apollo camera :-) ) from Dr.
>T's big sale yesterday...

Now I am in trouble!  For those of you wondering how come Eric got his 
projector while you have not seen anything yet, please be patient!  I 
decided to ship the heavy stuff first so I can make room to reach the 
rest.

Eric's comments are right to the point.  In projection you can see all 
the mounting errors superimposed and magnified.  You can manipulate 
the relative positions of each frame with respect to the other.  You 
can see and study the effect that different adjustments have.  That's 
a very educational experience.

While I was working on the projectors, I learned a few tips regarding 
maintenance of the TDC projectors.  Here is a typical maintenance 
schedule:

1. Move the focusing screw until the entire front assembly, containing 
the lenses and adjustments, comes out.  Examine how the different 
adjustments work.  Lubricate the screws so that they move freely.  
Clean the front and back surfaces of the lenses (this can be done 
without removing the lenses once the front assembly has been removed).

2. Open the condenser lens compartment and examine the lenses.  
Clean/blow the dust away.  Pull the polarizers out and check them by 
crossing them with a pair of projection glasses in front of a bright 
light source.  To clean the polarizing filters, I wash the assembly 
with warm water and shoap and blow dry.

3.  Turn the projector on to check the condition of the lamps and the 
air blower.  The blower can be accessed by removing the screws from 
the bottom.  It is recommended that you oil it every few years, but I 
could not tell where the oil should go in mine.

4.  Put everything back in place and check a projected slide.  I like 
to use grease to make sure that all the controls turn easily and 
smoothly.  Focus the slide as suggested in the instructions.  If the 
slide carrier feels sticky, it could be taken apart, cleaned and 
lightly lubricated.  I have done this in my own (old style) carrier 
that has screws and can be taken apart (newer carriers cannot be taken 
apart).  It made a bid difference.  When the slide goes in and out 
smoothly, there is less vibration, which is always good.

In my TDC 116 I have replaced one of the two switches in the back with 
a 3-way switch which allows me to operate the blower with both lamps 
off.  This is s standard feature in the TDC 716.  I always thought 
that this is a good feature that extends the life of the bulbs, but I 
recently read that the life is extended when they are allowed to cool 
down slowly.  I don't know if that's true or not.

Sometime ago the question was raised regarding replacing the lamps 
with modern halogen lamps.  No one offered any feedback.  According to 
Charles Piper, the light output of the lamps is the same if the lamps 
have the same wattage.  Others have commented that halogen bulbs will 
emit light which is whiter and this gives the impression of improved
brightness.  Finally, the size of the filament might affect the light 
output and sharpness (small filaments are usually better).  I would be 
happy to experiment with light bulb replacement but I have no 
experience with projection bulbs and don't know where to start.  Any 
ideas/suggestion?

George Themelis ("Yes, your stuff were shipped yesterday")


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End of PHOTO-3D Digest 1171
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