Control/Dimming Isolating Pairs of Fixtures

[GHSStageManager]

In my high school's auditorium, we have a total of 16 lekos, 4 fresnels, and 3-4 colored light bars. Currently, the lekos are arranged into eight pairs of two fixtures on the board. Currently, it is a bit awkward to work with pairs of fixtures, as some of the lekos are burned out/melted out (don't ask, bad electrician)

The question is: is it worth it to dedicate a 1:1 ratio of channels for each leko (one leko to one channel) rather than pairing them?

Thank you

 

[icewolf08]

In my high school's auditorium, we have a total of 16 lekos, 4 fresnels, and 3-4 colored light bars. Currently, the lekos are arranged into eight pairs of two fixtures on the board. Currently, it is a bit awkward to work with pairs of fixtures, as some of the lekos are burned out/melted out (don't ask, bad electrician)

The question is: is it worth it to dedicate a 1:1 ratio of channels for each leko (one leko to one channel) rather than pairing them?

Thank you

The question "is it worth it?" is totally subjective. If you feel like you want/need more control then it is worth it. ONe question for you is: are the twofered fixtures connected to the same dimmer or are the patched together on the console? If the former, then you have your work cut out for you as you will have to re-circuit.

Also, when you say that you have burned out/melted out fixtures, what do you mean? If the lamps are just burned out, replace them. If something is melted, what is it? In general, it is probably worth fixing your fixtures.

 

[mstaylor]

In my high school's auditorium, we have a total of 16 lekos, 4 fresnels, and 3-4 colored light bars. Currently, the lekos are arranged into eight pairs of two fixtures on the board. Currently, it is a bit awkward to work with pairs of fixtures, as some of the lekos are burned out/melted out (don't ask, bad electrician)

The question is: is it worth it to dedicate a 1:1 ratio of channels for each leko (one leko to one channel) rather than pairing them?

Thank you

It's always good to have one light/one dimmer. Whether you then pair them or use some as specials depends on the show. Many theatres don't have the available dimmers to do a 1/1 patch.

 

[GHSStageManager]

I'm not sure exactly how the fixtures are wired into our dimmer packs, I cannot access any part of the dimmer packs as the DMX is piped in from a sealed tube on the top and the packs themselves are mounted on the wall.

I say that the fixtures are "melted" because about a year ago, the music director attempted to replace the bulbs for a few fixtures. He said that he couldn't get the bulb seated correctly, because the structure to hold it in place wasn't all there (melted was the word he used.) Now, the auditorium had been worked on recently by a local electrician to accomodate the addition of 16 lekos - in addition to physically adding the instruments, the electrician added a new circuit dedicated to the lighting system. The director's theory is that the electrician screwed up the voltage level on the circuit.

Thank you

 

[Studio]

Look at the fixtures and where they are plugged in. Are there numbers near each plug? If there are numbers and these numbers are one per fixture then you can use the light board to change the light channel assignments. Look for a patch button.


If it looks as if two lights are plugged together then you have two lights on a dimmer and the only way to fix this is get more dimmers.

I would recommend looking at the patch assignments on your light board.

 

[Les]

I'm not sure exactly how the fixtures are wired into our dimmer packs, I cannot access any part of the dimmer packs as the DMX is piped in from a sealed tube on the top and the packs themselves are mounted on the wall.

I say that the fixtures are "melted" because about a year ago, the music director attempted to replace the bulbs for a few fixtures. He said that he couldn't get the bulb seated correctly, because the structure to hold it in place wasn't all there (melted was the word he used.) Now, the auditorium had been worked on recently by a local electrician to accomodate the addition of 16 lekos - in addition to physically adding the instruments, the electrician added a new circuit dedicated to the lighting system. The director's theory is that the electrician screwed up the voltage level on the circuit.

Thank you

The "sealed tube" is probably either flex conduit or EMT (electrical metallic tubing). The DMX is not what is run through this, its more than likely the home runs going to your raceways.

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And I don't think I would blame the electrician for the melted bases. You probably just have some bases that are in dire need of replacing, perhaps expedited by someone at some point in time using the wrong lamps in the fixtures. It would be hard for an electrician to get the wrong voltage to an instrument when they all come from the same dimmer pack, which will not produce more than 240v -- not enough to melt a base. Those bases are probably rated for something like 600v in reality. Just get some new bases in there - they only cost about $20 each. And don't open up the conduit leading to the dimmers, leave that to a qualified electrician .

 

[photoatdv]

See if you can find someone around there to help you out. If you have a college nearby someone from there might be willing to take a look and even teach you how to replace the bases and meter the power just to make sure its correct. I've volunteered helping several schools near me (everything from advice to running shows). If there's a real electrical problem you can't get around a qualified electrician, but a good (not high school student... no offense, but frankly you just don't typically get this kind of training at a high school) technician could verify that the power to the lights is good and replace whatever needs to be on the fixtures to make them fully operational.

 

[GHSStageManager]

Apologies for bring up an old topic but I thought it'd be better than starting a new one on the same topic...

Is there an easy way for my to check the validity of the power supply of the fixture? Or how about that the fixture is receiving the correct voltage/amps? I know my school has voltmeters, if those would be of any use to me.

Thanks,
Zach

 

[photoatdv]

By power supply do you mean the outlet? Or are we talking about automated fixtures now?

As far as outlets, if they're edison a cheap plug in outlet tester (the king with the leds) well verify the wiring is correct.

 

[icewolf08]

Apologies for bring up an old topic but I thought it'd be better than starting a new one on the same topic...

Is there an easy way for my to check the validity of the power supply of the fixture? Or how about that the fixture is receiving the correct voltage/amps? I know my school has voltmeters, if those would be of any use to me.

Thanks,
Zach

I guess the question is what are you trying to test? Or is something giving you clues that there is an issue?

 

[GHSStageManager]

Basically, I am trying to determine if the fixtures themself are at fault or is it the outlet that we are plugging them into - without risking good equipment in the test.

Thanks

 

[shiben]

Probably the easiest way is to use a multi-meter, set the dial for whatever you happen to be testing, and pop it into the plug as per the instructions that come with it. Although, come to think of it, what you really need is an oscilloscope, to find out how screwed up the wave form is.

However, I am going to guess that the line voltage is not screwed up, as that would be rather difficult to do, short of hooking up the incorrect line, but i doubt anything would work if this was done. If I had to guess, I would say that the lekos you have are not maintained regularly, and the bases have corroded and arced to the point of not being usable. This type of problem is fairly common, and as mentioned about it costs about 20 bucks to get a new one. The repair is also fairly common, and a qualified person can teach you how to do it in under a half hour. As was mentioned earlier, find a local college with a theater department. Most of us working at/going to school at colleges would be perfectly willing to come over and show you how to do this type of repair.

 

[GHSStageManager]

Thanks for the advice shiben, I will give the local Polytechnic School a ring on Monday and see if they'd be willing to show me how to deal with this problem. I've ran a search on maintaining lekos and found a lot of articles on generic fixture maintenance, but do you know of anything specific for specific fixtures?

Thanks again

 

[icewolf08]

Basically, I am trying to determine if the fixtures themself are at fault or is it the outlet that we are plugging them into - without risking good equipment in the test.

Thanks

Odds are the problems lie completely in your fixtures. As has been mentioned, you probably have bad lamps or bad lamp bases. Ironically, the safest and easiest way to test if a circuit is working is to plug a known working unit in.

You can use a multi-meter to test, but if you have never used one before, you should get someone to teach you how. The manual can only tell you so much, and it won't show you how to use it safely. You might also consider picking up a gamcheck as it is a very easy to use and safe diagnostic tool that requires very minimal training. They are not cheap, but neither is a good multi-meter. A gamcheck can actually give you more information than a multi-meter in some cases.

The other thing that you can do is pull the burn bases off the suspect fixtures as the odds are that is where the problem lies. If you can tell us what kind of fixtures they are (what brand) then we can tell you what best to look for and what parts you might need to make repairs.