The scanamp cage in my machine in Washington DC in 1980/81 was vertical opposite from the wall of the enclosure where the laser was mounted. I put an Allen wrench set on top of the cage when we installed the system and didn't find it again until packing back up six months later. Perhaps the reason for moving the cage was Bob Painter's experience in Nashville. They hooked up to the planetarium's cooling water supply, and couldn't figure out why the water was making a hissing noise. It turns out the cooling water was at 90 PSI, and the hissing was the emergency over pressure bypass trying to dump into the drain line. There was also a pressure indicator and power switch right near the original scanamp location. Eventually the over pressure blew the hose off the pressure indicator and hosed the exciter and scanamps. Bob said the prettiest blue flames came out of the top of the projector...
"There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso