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> Converting Spitz Constellation Projectors, From Hard to get GE 82 bulb to long lasting LED's
Ron Walker
post Jul 6 2014, 06:03 PM
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The more constellation outline projectors I have, the more I want. I really like the projectors that came with the Minolta but they appear very hard to get (if anyone is junking some please look my way). I think I will be able to run six that will follow the projector (and possibly twelve if I try that reverse diode trick) but right now I am running three which is certainly not enough. Having twelve would allow a complete zodiac show and be more then enough for any show of Spring, Summer, Fall, or Winter constellation show. Adding three more right away would be super great as it would allow me to expand a bit on my "Intro to the planetarium and night sky" show for which I have requests for six different shows with three coming up this next Saturday.

I was going through my "good junk" box of projectors and came up with three Spitz constellation units as well as the transparencies that came with them. Another gift from Mr. Brent no doubt as I have no other idea where they would have come from.

Attached File  original_projector_together.JPG ( 19.11k ) Number of downloads: 0


These projectors use a hard to find (for me anyway) GE 82 bulb that generates a fair amount of heat. The bulb fits in the socket that sticks out the top of the projector. The lens is to the right.

Attached File  original_projector.JPG ( 20.11k ) Number of downloads: 0


Taking the unit apart allows one to see the rather large bulb and mounting plate that holds the bulb socket. Originally the projector mount is threaded into a 1/4-20 screw hole on the back just opposite the lens.

Attached File  new_part_nd_machined_old_part..JPG ( 21.8k ) Number of downloads: 0


Since the new LD needs to be in line with the optical parts I needed to drill out the threaded hole to make way for the LED socket which is a standard miniature bayonet mount bulb that I have been standardising on. I also made a simple plug out of aluminum rod and tapped a 1/4-20 hole in it.

Attached File  new_parts_ready_to_install.JPG ( 27.91k ) Number of downloads: 0


The new plug now goes on the original support device which is a basic simple camera mount. The LED is now ready for insertion into the back of the projector in the new hole prepared for it.

Attached File  new_LED_installed.JPG ( 27.02k ) Number of downloads: 0


Next the LED with socket is placed in the new hole at the back of the projector and slid in so the diode is the proper distance from the condenser lens for proper illumination.

Attached File  new_support_plug.JPG ( 19.64k ) Number of downloads: 0


The new support plug is mounted in the original support block from the original bulb.

Attached File  projector_complete.JPG ( 20.41k ) Number of downloads: 0


Finally assembled and ready for a new life with a long lasting and cool LED.

For anyone out there considering this conversion, please remember the the power supply most be converted as well. The original GE #82 lamp is a 6.5 volt 7 watt unit pulling slightly over one amp of power. The LED that I am using runs at 12 volts pulling less then one watt of power pulling about 0.08 of an amp. This is not a problem for me as I am rebuilding all of the control circuits anyway.
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