New 35mm install for Theatrical Exhibition

[Phillip Grace]

Looking again at the photo of the drive side of the machine, there is a (probably) toothed belt drive between the sound head and the projector. Nothing really odd has been done to mate the two units. It might be easier to find and exchange complete R3 or R4 sound heads which have already been upgraded to red light than to get hold of the individual parts to rebuild these two. The existing drive motor and pulleys could be swapped over the the new sound heads if necessary.

Does anyone have a comment about the light output of the Xenex LP 1000 lamp houses? 1 Kilowatt for a 28 foot screen seems a bit optimistic.

[Mark Gulbrandsen]

Yes, 1KW is being hopeful for sure. 2KW would be optimum and with the glass reflectors the lamps will last a very long time. I once replaced a Strong Future running at 140 amps with a 3kw Xenex and the light went up 25%. The Xenex can take any size lamp up to 4kw with appropriate adapters if needed. The adapters are probably still available for that lamphouse. You will likely need larger rectifiers, but check the label on the ones you have and see what the DC current range is.

[Jacob Tutt]

Phillip - I am with you here. The drive side on both sound heads is complete with motors, so I will keep them as parts when I find some replacement heads.

Mark - That's great to hear! The Xenex appear easy to clean and maintain, and the mirror inside them is pretty cool. Unfortunately, I don't have rectifiers.

[Dave Macaulay]

Bored, I started cleaning up a bit and came up with a CC shutter gear unit. Here it is: the gear drives off the vertical shaft from a second gear (same as used for the main shutter shaft) a single shutter shaft is used unchanged for what looks like a single shutter but with less wide blades. The counter rotating shutter (also less wide blades) mounts on the larger diameter extended tube. Those shutters are hard to find. The image is brighter overall from the longer "open" time but also gets brighter towards the middle due to the shutters closing last and opening first there.

[Kenneth Wuepper]

Yes. This is the same effect that you get with the rotating drum shutter. Basically a fast operating 2 blade shutter.