"How did you manage to keep other
uninformed people away from these boards? "
Most people were too scared to touch the things. We also had a few signs and locked the door to the room.
"We also plastered "Danger - High Voltage"-signs all over these things, as well as open the company switches (the sources of electric power) and lock them out when not in use. Other circuits, such as house lights and stage work lights, were controlled from a permanently installed board somewhere nearby."
I don't remember pulling the power co's switch (located in the basement), but there are some knife switches that disconnect the board's various circuits so that if, say, the aisle lights needed repair you didn't have to shut the whole thing down.
"It's interesting that your system is/was still in use as of late 2003."
I'm guessing that there was no money to upgrade. This is a small northern Iowa town of about 2,500 and most likely they follow the motto "If it ain't broke, don't fix it." If you think of what it would cost to pull that old beast out and replace it with something modern, you can see why it survived for 80+ years.
As an interesting side note, many of the old dimmer boards have survived and are still in daily use in some of the old movie palaces of the 1920s. A great example is the Byrd Theatre in Richmond, VA. I went to their website (http://members.tripod.com/~g_cowardin/byrd/index.htm) which tells a great deal about the place and how it's practically unchanged since 1928.
"BTW: Did your system use a lot of those old 50 amp stage plugs and plugging boxes - the kind with the long flat copper blades on each side of an insulating body/handle that mated with the equally large porcelain receptacles?"
I do remember something of that nature, but it was one of those things I never really paid attention to.
