Film-Tech Forum ARCHIVE: Auditoriums lights Flicker

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Posted by Tim Johnson (Member # 1403) on 01-11-2005, 07:27 PM:

I am having trouble in one of my auditoriums with the side lights flickering when the dimmer goes to half light. When the lights go up they don't flicker at all, I went through the dimmer and tighten up all of the connections, I checked the connections in the service box to make sure all looked good.

EQUIPMENT LIST
Xetron XD-3K Dimmer
Component Engineering TA-10 Automation
Simplex Projector

I guess what is puzzling me is the fact that they don't flicker all the time, only in the half light mode. If it would be a problem with the circuit or the light fixtures you would think that they would flicker all the time. Any suggestions ?

Posted by Aaron Sisemore (Member # 145) on 01-11-2005, 08:16 PM:

First thing to check would be for dirty control potentiometers, most notably the one that sets the half light level.

-Aaron

Posted by Gordon McLeod (Member # 33) on 01-11-2005, 09:50 PM:

also check if there are any relays in the dimmer older xetrons used relay latchs and the contact might be dirty

Posted by John Walsh (Member # 168) on 01-12-2005, 07:14 AM:

XD-3K dimmer does use smaller DIP-style relays, but since it's working (except for the flicker) they are probably OK.

Is yours a dual-channel unit? Sometimes when each channel on dual channels units are connected to different phases, one will flicker as the dimmer rasies or lowers. Did it always flicker, or just start? Did anyone do any electrical work there recently?

Posted by Frank Angel (Member # 248) on 01-12-2005, 09:25 AM:

We just opened a newly renovated lobby that has every light on a large dimmer system. Aside from the fact that the installion contractor didn't follow the electrical engineer's design and wired all lights incorrectly so you can't dim the areas that were assigned to their respective dimmers (some light fixtures were in the same area wired to dimmers for another area), we found that a particular set of accent lights wouldn't dim properly. The circuits were tested, the dimmers were tested, everyone scratched their heads for a few days. The lights would dim to about 2/3rds and then some would start to flicker, some would go out. When when the dimmer was about about half, the lights that remained on would just blink out randomly. Bringing the dimmer back up and at about half-way up, the lights would flicker back on....not dim on from zero.

Come to find out when we opened the fixtures which were supposed have been outfitted with incandescent bulbs, were instead supplied with compact flourescents. Ya can't dim flourscents and if you keep trying to, keeping them at anything but full on or full off, it won't be too long before their nice little compact ballasts will burst into flame.

Any well-intentioned house maintenance crew happen to relamp your side lights recently, Tim? [Eek!]