microstar
Well-Known Member
Forgive the length of this post but I thought telling the whole story would be worthwhile.
On Monday the AV contractor and I wired in a new intercom power supply to a sound system installation at a local school and tested it. On Wednesday afternoon, the drama teacher sent me a series of text messages:
TEACHER'S TEXT #1: We much appreciated the repair, Unfortunately, the work done has caused something to go horribly wrong with our lighting board. Ever since the install, the lighting cycles on almost like they're on a chase sequence. I shut down, reloaded, checked cues, even BLACKED OUT the board, and it's still having lights on the first, second and third electric flashing on.
TEACHER'S TEXT #2: We have a show tomorrow. Any ideas what may have happened?
TEACHER'S TEXT #3: I should have informed you earlier, but we've had a two week turnover time between assemblies and shows each month. During spirit assembly, when music plays, lighting system flashes on and off uncontrollably.
MY RESPONSE: So this problem PRE-DATES the Monday intercom installation?
TEACHER'S TEXT #4: It only flashed previously when sound system was playing music. Now it does so all of the time.
MY RESPONSE: Please get approval for an emergency service call. I will need to come tonight after all the students are gone after your rehearsal.
A couple of hours pass and I get a call from the Head of Maintenance to make the service call and he will issue a PO.
I show up at 6:30PM as the last students are leaving. Stage and houselights are on and they are not using the sound system. Nothing is flashing/chasing so I ask the teacher what I could do to make it to happen. She says black out the houselights and set the board master to zero. I do that and wait....and wait.... and wait. Nothing happens.
A DMX to Electro Controls multiplex converter box is setting next to the light board. I had installed it in 2008 when I replaced the original Electro Controls console with a DMX board.
I turned it around to look at the front and the POWER and DATA LED indicators were alternately flashing at a furious pace, instead of the normal constantly on.
Fortunately I had brought along a replacement converter and its wall wart power supply, so substituted my converter and the POWER and DATA lights continued flashing.
Then substituted my wall wart and the flashing stopped, with both LED's constantly on. Then hooked the original converter back in, powered by my wall wart, and both LED's stayed constantly on. I then checked the voltage output of the wall wart without a load and it read correctly, with a smooth output.
Oddly enough I never did see the stage/houselights flash/chase during my time there. I stayed around for about 20 minutes to make sure everything was OK.
They apparently did their show the next day without incident and I've received no reports of further issues.
Later, I took apart the bad wall wart which was a linear type with a transformer, bridge rectifier, and capacitor. The capacitor was domed and tested bad. I soldered in a new capacitor, re-checked the output, and hooked it up to my DMX to EC converter. The LED's indicated properly. Moral of the story.... bad power supply capacitor... NOT the installation of the intercom power supply, NOT the sound system, and NOT the light board. Believe only a small portion of what the reported "causes" are!
On Monday the AV contractor and I wired in a new intercom power supply to a sound system installation at a local school and tested it. On Wednesday afternoon, the drama teacher sent me a series of text messages:
TEACHER'S TEXT #1: We much appreciated the repair, Unfortunately, the work done has caused something to go horribly wrong with our lighting board. Ever since the install, the lighting cycles on almost like they're on a chase sequence. I shut down, reloaded, checked cues, even BLACKED OUT the board, and it's still having lights on the first, second and third electric flashing on.
TEACHER'S TEXT #2: We have a show tomorrow. Any ideas what may have happened?
TEACHER'S TEXT #3: I should have informed you earlier, but we've had a two week turnover time between assemblies and shows each month. During spirit assembly, when music plays, lighting system flashes on and off uncontrollably.
MY RESPONSE: So this problem PRE-DATES the Monday intercom installation?
TEACHER'S TEXT #4: It only flashed previously when sound system was playing music. Now it does so all of the time.
MY RESPONSE: Please get approval for an emergency service call. I will need to come tonight after all the students are gone after your rehearsal.
A couple of hours pass and I get a call from the Head of Maintenance to make the service call and he will issue a PO.
I show up at 6:30PM as the last students are leaving. Stage and houselights are on and they are not using the sound system. Nothing is flashing/chasing so I ask the teacher what I could do to make it to happen. She says black out the houselights and set the board master to zero. I do that and wait....and wait.... and wait. Nothing happens.
A DMX to Electro Controls multiplex converter box is setting next to the light board. I had installed it in 2008 when I replaced the original Electro Controls console with a DMX board.
I turned it around to look at the front and the POWER and DATA LED indicators were alternately flashing at a furious pace, instead of the normal constantly on.
Fortunately I had brought along a replacement converter and its wall wart power supply, so substituted my converter and the POWER and DATA lights continued flashing.
Then substituted my wall wart and the flashing stopped, with both LED's constantly on. Then hooked the original converter back in, powered by my wall wart, and both LED's stayed constantly on. I then checked the voltage output of the wall wart without a load and it read correctly, with a smooth output.
Oddly enough I never did see the stage/houselights flash/chase during my time there. I stayed around for about 20 minutes to make sure everything was OK.
They apparently did their show the next day without incident and I've received no reports of further issues.
Later, I took apart the bad wall wart which was a linear type with a transformer, bridge rectifier, and capacitor. The capacitor was domed and tested bad. I soldered in a new capacitor, re-checked the output, and hooked it up to my DMX to EC converter. The LED's indicated properly. Moral of the story.... bad power supply capacitor... NOT the installation of the intercom power supply, NOT the sound system, and NOT the light board. Believe only a small portion of what the reported "causes" are!
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