Why won't it light? Troubleshooting conventionals

[derekleffew]

Inspired by:

...The next thing I want to develop is an exercise where they learn how to troubleshoot....I do try to cover it some by teaching them that the least likely reason for a light to not light up is a blown lamp. At the very least check all other possibilities before you grab a new HPL.

And one of my test questions:

_____ If a fixture does not light up when the board operator calls it up, what’s the FIRST thing to check?
A. Lamp; B. Dimmer; C. Multi-Cable; D. DMX Cable

It appears [USER]NevilleLighting[/USER] and I already have differing opinions.

Somewhere on here we once had a discussion regarding "Do you check (X) The most-likely possibility, or (Y) The easiest-to-check possibility; when trouble-shooting?" but I can't find that thread, so let's start over.

(Z) Maybe a list of all the reasons why a light might not light, and then after a week we'll prioritize them?

And since it's been a while, let's make this a OotD--students only for one week, please.

 

[CrazyTechie]

I would say the lamp is the first to be checked as it is the easiest to access in most cases and from there I check to make sure the circuit works by plugging in a known working light and trying the channel again. If that does not work I go check the dimmer racks for a flipped breaker and to make sure there is a signal to the dimmer, but if it does work I proceed to check the cabling between the circuit and the instrument.

In list form:
-Check lamp
-Check circuit with a working instrument
-If that does not work go check the dimmer racks for a signal/flipped breaker
-If the circuit works check the cabling from the circuit to the light

 

[DuckJordan]

Your test question should have another option. Check the patch!

The order I always go in is whichever is easiest. It generally turns out like this.

Patch
DMX
Lamp
Extension
Circuit
Dimmer

In that order. I've almost always found it to be an extension in our space.

 

[CrazyTechie]

Your test question should have another option. Check the patch!

Ah! I forgot the patch, and if I recall correctly the last show I did ME for I had switched a light when I patched it into the board so It's definitely something that should be checked.

EDIT: While troubleshooting why a light wasn't turning on and after finding out that the breaker on the dimmer kept tripping after I would turn it back on, I went to check the extension cords and I found this upon opening one of the ends up and quickly determined why the breaker kept tripping:

 

[NevilleLighting]

[Mod note: This post had previously been hidden, and is being revealed now (05/26/11), one week after the original question was asked.]

Derek, I think you make a good point there. Part of the check also depends on where you are in the process. Early in the process my first reaction is to check patch. Second, I check to see if juice is getting to the fixture. Third I give it a continuity check. Fourth I go after the lamp. If the lamp passes a visual inspection I may open the plug, or at least tug on the wires. I also give the socket a good inspection. In one theatre I have a lot of 360Q's and lamp seating fails five times more than the lamp. I see students reach for that HX600 way too early in the process. It's an expensive rush to judgment. All too often I hear "light doesn't work. someone get me a lamp".

I can see an easy point in going for the continuity check first, especially if the show is running and all of the changes and gremlins have been worked out.

 

[CrazyTechie]

I'm not sure what you mean by making sure that juice is getting to the fixture but if I had to guess it would be making sure that a load is capable of traveling to the fixture. The only problem with a continuity check is that it doesn't tell you if the cable or whatever you are checking will actually take a load. I had an extension cord that passed a continuity check but it did not take a load, the reason was that the wires for the hot were just barely touching the pin so that a signal could be sent but not enough for power to go down the line.

As long as you are doing both checks on the cable everything, in my opinion, will work out as far as cables are concerned. However, if you just do continuity checks on the cables then you are setting yourself up for a cable that wont take a load in the middle of your rig that you have to switch out when you do a channel check.

 

[derekleffew]

...I went to check the extension cords and I found this upon opening one of the ends up and quickly determined why the breaker kept tripping:

So you're saying those letters N, G, H (inside a Union Connector plug) or words WHITE, GREEN (inside a Bates connector) actually mean something? I thought electricians didn't need to know how to read, just tell colors.

Black to Brass, White to Silver, Green to Green.

 

[techieman33]

So you're saying those letters N, G, H (inside a Union Connector plug) or words WHITE, GREEN (inside a Bates connector) actually mean something? I thought electricians didn't need to know how to read, just tell colors.

Black to Brass, White to Silver, Green to Green.

I don't remember ever seeing brass, silver, and green screws on a stage pin connector, and I think I've had most if not all of the major manufacturers connectors at one point or another.

 

[CrazyTechie]

So you're saying those letters N, G, H (inside a Union Connector plug) or words WHITE, GREEN (inside a Bates connector) actually mean something? I thought electricians didn't need to know how to read, just tell colors.

Black to Brass, White to Silver, Green to Green.

I thought so too but apparently electricians need to learn how to read as well. Although we could try to teach a "color-by-number" system and number them but we'd have to remember how to count as well.

 

[JChenault]

Derek

I think there are actually be two questions here.
1 - during dimmer check, a lamp did not come up. What do you do to troubleshoot.
2 - You have hung a circuited the show and a lamp does not come up. What do you do to troubleshoot.

Two very different scenarios with ( at least for me ) very different troubleshooting paths.

( Ignoring touring and rep houses which make things too complex for this thread. )

 

[ruinexplorer]

Your test question should have another option. Check the patch!

The order I always go in is whichever is easiest. It generally turns out like this.

Patch
DMX
Lamp
Extension
Circuit
Dimmer

In that order. I've almost always found it to be an extension in our space.

If you almost always find that it is a problem with the extension (air gap?), why is that not your first check? Just for point of discussion.

 

[DuckJordan]

If you almost always find that it is a problem with the extension (air gap?), why is that not your first check? Just for point of discussion.

Because while it may happen to be the extension at most times at this venue it does not necessarily happen at another. Its also good to point out that right before i came they had a lighting professor retire (he was good at designs not so good at equipment upkeep) and most of the extensions were created during his time here. So as those bad cables are found and fixed the problem is slowly starting to become less common.

Its also good to follow a routine as it helps create a familiarity in how to troubleshoot. No steps skipped means no steps forgotten.

 

[FlashBang]

When hanging lights I always have a long extension of Edison/T3 plugged into a house circuit. Its easier/quicker to grab the extension and plug in a light then to actually remove and replace a lamp when troubleshooting (and if its focused, you won't disturb that).

Given that, my list would go:
Patch
Lamp (plug into known working circuit)
Circuit (test by plugging known working fixture)
Extension (if not plugged direct)
Dimmer

 

[mstaylor]

May I suggest to think about PARs as well as lekos and fresnels. There may be differences or additions between the two. I will only say I wouldn't follow any list I have seen so far.

 

[DuckJordan]

May I suggest to think about PARs as well as lekos and fresnels. There may be differences or additions between the two. I will only say I wouldn't follow any list I have seen so far.

This got me thinking, and its something that also commonly happened.

Patch
DMX
Shutters/Iris
Lamp
Extension
Circuit
Dimmer

 

[NickVon]

Ahh the classic, Shutters never got pulled failure.

I think JChen, hit it on the head. Depending on the circumstances i think the process changes.

during a "hang" i'd first check the Shutters and Patch.

If something has failed during dimmer check i think i'd start at breakers then proceed to go up to the instrument and check a lamp failure. then extensions.

I do asribe to the check the easiest to get to failure points first (especially in my venue where it's a Genie lift to get to the grid.

 

[mstaylor]

I am an arena guy and getting to the grid means either a rigger or a 60ft lift. It changes my thought process.

 

[chausman]

WAIT!!! Are you all saying there should be some sort of systematic checking method that we use for all of out fixtures?

I would just check what is easiest. If I'm using the RFU, I would probably check that I brought up the correct channel and then that it is plugged in correctly and where I want it to. Then, a lamp would be my next check, since I can check that without leaving the fixture. Then start checking cables and breakers. (by swapping with known-working cables and fixtures nearby)

 

[derekleffew]

Does the methodology change depending on what tools one has on one's person?

What tools might one find beneficial?

 

[chausman]

Does the methodology change depending on what tools one has on one's person?

What tools might one find beneficial?

RFU. (and now to get up to 10 characters)