I would agree with Les as well.
My experience and research tells me that there were a handful of tweaks and revisions to the 902/Dynaspot over the years. By the late 1980s, there were actually 3 different models of this spotlight.
At that
point the 902 had a beam spread of 1.9° to 33°, used two 4.5" x 9" PC lenses, and had no cooling fan.
The 902 Jr. had the same optics, but lacked a color
boomerang, which allowed it so be about 12" shorter.
The Dynaspot had a beam spread of 1.5° to 19°, used one 4.5" x 12" PC
lens and one 4.5" x 6.5"
lens. Presumably the cooling fan was added to prevent the thicker 4.5" x 6.5"
lens from cracking.
The fact that yours has a cooling fan but is still listed as a 902 suggests that yours is likely from the early to mid 1970s.
I'm not sure exactly when production was discontinued, but I would guess sometime in the early 1990s.
These spots were once everywhere (and there are still plenty of them around). They seemed to be standard equipment for every elementary and Jr. High school in the country!
The reason they are so inefficient is because they are basically an advanced design plano
convex spotlight that has an
iris,
guillotine shutters and a color
boomerang.
The
Altman 1000Q (which was
Altman's response/copy of the Strong Trooperette) was a pretty major
advance in that it used a 1000
watt halogen lamp mounted in an
axial ellipsoidal reflector which produced more than double the output of the 902 design with a 50% reduction in wattage.
I have an early 902 in my inventory. I'll post some pictures of it the next time I get to my storage facility.