Lighting Rig Problem?

[STCM_Tech]

Hey Guys

 

So our lighting rig has taken on a life of its own recently, it first started off with random lights flickering on and off. Or lights coming up when another fader was up for a different light. It has now got an added symptom of an electric rattling/humming sound coming from the bars.

 

Initially I thought it was our desk as it is an old Zero88 Elara which has taken a lot of use. But with the humming/rattling I guess it cant be the desk.

 

Details of our set up;

We have Zero88 Chilli Dimmers, with 48 channels. and DMX running up into the bar as well as two 13A sockets up in the bar too.

It was all installed around 2004 I think by Stage Electrics.

 

Obviously we are looking at getting someone in to look at it but I was wondering if anyone has seen or hear of this problem before?

 

Thanks

[sleah]

The two problems may or may not be related. The flickering issue could be DMX related, as simple as not having a terminator. An yes, it could have been fine for years but only just started to happen, even if nothing has changed. Been there, done that!

 

The rattling and humming is more of worry. You haven't mentioned what's on the bar, lantern wise.

 

Is the sound constant all the time the system is powered?

Is it only when certain lanterns are on?

Does it vary depending on which lantern is on and vary with dimmer level?

It could possibly be the internal wiring buzzing, maybe due to overload or lose connection(s).

 

There may be other reasons that others cleverer than me will suggest.

Personally, I'd give it a full inspection, socket covers off etc, but only if your competant. Otherwise get someone in who knows about these things! Clearly you've got that covered :)

I'd suggest not going near the bar with the system powered up until it has been verified as safe.

 

One posibility is a lose connection floating round that could be touching the metal parts intermittantly - it can depend on how much power is flowing as to how much it 'rattles'.

 

Be safe!

 

Edited for more SPaG than is healthy for one post... :(

[STCM_Tech]

The DMX termination idea is a good shout. But like you said the few DMX fixtures flickering is not my main worry.

 

On the rig we have;

 

3 Profiles

9 Fresnels

1 Super old spot of some kind

 

DMX:

2 LED Pars

1 Strobe

 

The sound, is not always there. I have heard it both when lights are up and when no lights are up. It seems to not be coming from a particular place in the bar either.

 

Cheers

[alistermorton]

The sound, is not always there. I have heard it both when lights are up and when no lights are up. It seems to not be coming from a particular place in the bar either.

 

Rodents?

 

 

 

[sleah]

The DMX termination idea is a good shout. But like you said the few DMX fixtures flickering is not my main worry.

 

On the rig we have;

 

3 Profiles

9 Fresnels

1 Super old spot of some kind

 

DMX:

2 LED Pars

1 Strobe

 

The sound, is not always there. I have heard it both when lights are up and when no lights are up. It seems to not be coming from a particular place in the bar either.

 

Cheers

 

It may not be the dimmers then. As you have the LEDs and strobe up there connected to hard mains, it could be the hard mains supply at fault as much as it could be the dimmed supply.

 

It would be worth fully disconnecting the LEDs and strobe (with the system power off first of course!) to eliminate their electronics from being the cause.

 

Be interesting to hear what the problems is when it's resolved. (assuming the exact course is discovered).

[patrick_keys]

Sounds like some good old fashioned troubleshooting is required here before you start taking things to bits.

 

Start with everything off, and verify that there's no rattling (simple I know, but sometimes it's something else in the room!). Disconnect all of the fixtures, then try one at a time until you can repeat the problem. Then try swapping the sockets that the fixtures are plugged in to - does the problem stay with the fixture or the socket? Rinse and repeat as required.

 

What you really need to do is to reduce the size of the problem - it's unlikely to be the whole rig - much more likely to be a lamp base that has seen better days. I'm guessing that your supply is RCD protected and your rig is earthed too?

[STCM_Tech]

Thanks for the advice, it is coming up to it needing inspecting anyway so I think we will probably go with an early inspection. But I will definitely try disconnecting the LED fixtures from the mains and DMX to see if that does anything.

[mrboo]

I dont like saying it but it maybe worth getting the lights pat tested. as it maybe a live earth. I had a 13amp plug do it on me make a noise as some one pulled on the fexi.

[Barreller]

I dont like saying it but it maybe worth getting the lights pat tested. as it maybe a live earth. I had a 13amp plug do it on me make a noise as some one pulled on the fexi.

[ianknight]

The lights flickering may well be a couple of the faders starting to fail on the Elara - they get noisy either at top end or bottom travel - spares are still available for the Elara so worth getting a Zero88 repairer to have a look at.

 

For the noise coming from the rig - get an electrician to look at it ASAP (and really - ASAP) and check the neutral terminals on the Chilli and then follow them back to the mains distro feeding the unit (whilst he/she is doing that - check the lives are tight too). There may be some noise being induced in the triac processors by a sparking terminal - a sparking terminal at some point will overheat and cause more damage than 5 minutes checking with a screwdriver will cost.

[Barreller]

I don't know why you don't like saying it Mr Boo. That's the best advice so far!!

[adam2]

A rattling noise if actually electrical in origin, is potentialy dangerous as it could indicate various faults, I would STRONGLY AGREE with the previous advice not to go near or touch the equipment until it has been inspected by a competant person.

 

IMHO the noise is more likely to be non electrical in origin. Rodents, birds on roof, noisy ventilation, wind, noise from another building, etc are probably more likely, but until this is determined it would be best to be cautious.

[mrboo]

I don't know why you don't like saying it Mr Boo. That's the best advice so far!!

http://www.bbc.co.uk/news/uk-politics-17929112

 

As pat testing is not needed for most cases but is worrying sold as needed to have done. but does sound like a case that if every item been on a pat test meter your 100% sure there no earth leak so it would then lead to the house power and would need action asap I would say cut the power until a sparky been over the full system at that point.

http://www.hse.gov.uk/electricity/faq-portable-appliance-testing.htm

 

 

[Albatross]

I have seen something similar here when we had a neutral connection issue.

The neutral on the 3 phase connection to our dimmers was loose and arcing across. At times things seemed fine but random lamps on the dimmer would flicker.

 

Some lamps; such as PAR 64's, will buzz when dimmed and perhaps that's part of what you're hearing.

 

Your problem does sound power related!

[Ian der Laan]

There can be lots of reasons for these symptoms and speculation is often just a stab in the (flickering) dark.

 

 

As previously stated, troubleshoot from scratch and and get fixtures PAT tested.

 

After PAT test:Try operating the generic fixtures using test channels to take the desk and DMX out of the equasion, then work your way up as previously described.

 

Try using one dimmer rack at a time (if you have more than 1).

 

Try only using the 13A kit.

 

Try replacing cabling (especially DMX).

 

 

You will eventually find the answer!