Found this thread quite interesting, and decided to join CB to share my thoughts.
At first I was thinking about a possible heat problem, the ambient temperature in the rack being too high. When I was in college, we had two
ETC Sensor48s and a
Unison mounted about 12-15' above the
stage on a mechanical
platform, with the roof about 8' above that. In the summer if the A/C wasn't on, it would get hot enough up there to cause the racks to overheat, and any lights on would start to flicker. This would usually start to happen when the temperature up there hit 88-90 degrees. The only way to stop the flickering was to make sure the A/C was on, and/or set up a box fan blowing on the racks. We had it checked, everything was done right, CEMs swapped out, yet we would still have the flickering problem. At my
current theatre (and others that I've worked in) we have a Sensor 48 rack and its been much hotter but have never had any problems. I know this obviously isn't the issue thelatinist is having at this
point, but I figured I'd share that in case anyone else has experienced that kind of problem.
Now, on to my thoughts and questions for the OP.
Do you have a
Gam Chek? It would be a very useful tool for you to use for troubleshooting. You can do a lamp check on all instruments, if on one the check fails, but you know the lamp is good, I would take apart the
connector and check for proper wiring. The check will only pass if the hot and
neutral are connected correctly, and will fail if the neut/gnd are reversed. Use the
Power Check to test all of your connectors in your
outlet boxes. While it won't check if
neutral and
ground are reversed, you can rule out the possibility that hot and
neutral aren't reversed, which could be energizing the
fixture and pipe via the
ground, especially since some of your instruments had the
neutral/
ground reversed in the pin
plug. Last, you can check all of your
stage cable for
continuity, to make sure that hot and
ground aren't reversed. I worked as ME for a show at a local college, grabbed a
jumper, and was trying to figure out why the pipe was buzzing. So much of the equipment there was in such bad shape, and some moron kid decided to try to fix it and just hooked the wires back up to any screw in the
connector. Hot/
ground reversed. Glad I wasn't working on that
instrument while the
dimmer was hot.
Did you shorten the wires in the connectors where the
insulation was cut back too far?
Have you tried plugging those
cyc lights into a different
circuit, maybe put at least one on a
circuit that was flickering with another
fixture, to see if the
cyc light flickers?
Have you had a chance to open up the
outlet boxes? Check for any loose connections, any cuts in wires? Do all the circuits share a
neutral, is it loose/bad connection? Are there non-dims also in the same
outlet box? Are the neutrals crossed, ie the neutrals from the dims going to the subpanel that feeds the non dims, or vice versa?
You did mention moving the
outlet boxes recently, did the flickering start after you moved them, or had it been happening before that?
Did you check the wires in the lugs on the bad
phase? Does it show signs of arcing? I would try what others have mentioned before, and swap the "phases" to see if the problem changes at all.