P3D Halogen viewer bulbs

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Bob Aldridge writes:
    
>Once apon a time, there was a chap [...]

Interesting story... thanks Bob!  But you didn't tell us who that
chap was :-)

>The designs have been imitated in a number of ways since - Dr T got the 
>idea for Quartz Halogen lighting, secondhand from someone who had seen 
>the conversions.

Not really... Reel 3-D started marketing the 0.8A halogen bulb in 
the USA.  This bulb is taller than regular bulbs so it would not 
fit in many stereo viewers, including the Realist red button.  I
liked the bulb so I modified my viewer's base for the bulb to fit.
I started selling these bulbs myself and modifying viewers for 7p
and also modifying the base of the red button for the halogen bulbs.

Finally, I figured out how to make the halogen bulbs a bit shorter 
(so no viewer modification is needed) and also how to "frost" the 
glass envelope for diffused uniform light.  IMO, these frosted bulbs
which have a screw base and come in a variety of ratings (2.5V 0.8A, 
2.5V 0.5A, 6V 1.0A, 6V 1.1A - I stock all of them) provide the best 
light for stereo viewing in a properly tuned viewer.

When using high current/low voltage bulbs in viewers, you have to worry
about light flickering, which is caused by oxidation in the switch
contacts.  I am now looking into installing a "microswitch" like Dave
Burder has done in the modified Sterolists.  It is not clear to me how
these switches work.  Is there a contact made?  If it is, why would
these switches eliminate flickering? (as some people claim - I have no
personal experience)

-- George Themelis


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