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Avo Art rack/Power issues


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Final week of a 3 week job and we've had 12 Lamps go in a rig with 44 x S4's (750w). The last one actually exploded! Have also come in for switch on last week and none of the DMX worked in the roof, spent ages fannying around with cables before switching everything off and on again made it work.

Everything is powered from an Art Rack, gonna do a diagnostic Tuesday, (it's really un helpful that I've lost my nice multi-meter on this job http://www.blue-room.org.uk/public/style_emoticons/default/mad.gif)


I assume that the art racks distribute power to the modules like so? -


12 way module (Hot or Dim)


CH 1,4,7,10 Phase 1

CH 2,5,8,11 Phase 2

CH 3,6,9,12 Phase 3


Apart from a dodgy power supply (which is highly likely) any idea why we're having these problems?



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The Avo Art 2000 rack does indeed have that power distribution.

A Switch Module, (not the DMX Relay) has no need for the PSU to be on, The brain will only power the Dimmer control. The PSU inside is a std AT/ATX unit.

There are 3 small glass fuses on the control card, that you could check, if one of those has blown, that phase wont work.

Are the phase indicator neon’s lit up correctly? That will indicate if your 3 phase is good. if one of the fault neon’s is lit, you have a mains issue and should not be powering up the rack.

Hope that helps

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Justify that statement.

Sorry, that reads too blunt. What I mean is...can we have more info please.


Don't worry I'm not offended!


The venue use 24 x Codas for their house lights which the in-house guys say they are always having to replace the lamps (a couple every week or so). They say it's because the fixtures are knackered and they are on almost all the time but given my problem I'm thinking there might be something dodgy with the mains? The in house system uses an old rack of Avolites dimmers.


The Art-rack I'm using appears fine and is fully working across all phases. At the end of each night I'm following standard protocol and Dousing the lamps on all movers, dimming all generics to 0%, then tripping the 12 x breakers in the hot module of the rack (powering moveres) before killing the main breakers for each module, the reverse for switch on.


I am sending preheat from the desk.


This problem sounds like there are occasional voltage spikes in the supply? I've never known this many lamps to go in 2 weeks. I metered the Venues supply at 244v so if there was a small rise in voltage it's quite high to begin with.


Gonna check the system when I go in today but I don't think I'm going to find anything wrong unless I can record the max voltage over a day.


If there is a spike issue this must be from the mains not the dimmers (unless I'm mistaken)



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Well, I've metered the system at various points, PAT Tested the exploding fixture and relevant cables (that I could get to), had some one check the voltages whilst striking the movers and dimming the whole system and all seems fine.


Then, BANG, another lamp explodes and smashes a custom monochrome Gobo!! Glass every where,

I also had another lamp out on another fixture.

All my Lamps are HPL 750 240w, the faults are across phases.


I am right in thinking that Dimmers aren't going to spike with a stable supply? Surely the mains has to be dirty for this to happen? is setting a topset going to help if Dimmers/mains runs over 240v? I suppose it might make the spike less harsh but it seams that if there are spikes are high enough to make the lamps explode this violently 10% isn't going to be enough?


One of the exploding lamps was paired with another and that one was fine


Apparently the sound guy said last night he had a 9v battery explode on his table!!! (not next to any power or heat source)


So far the options are:


- Dodgy mains that spikes

- Dodgy ArtRack that spikes (unlikely)

- Dodgy batch of lamps

- Haunted venue


All suggestions welcome, I'm stumped http://www.blue-room.org.uk/public/style_emoticons/default/sad.gif


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Dodgy neutral somewhere in the three phase hookup?

That would cause all sorts of 'splodeyness from lamps, and is a farly popular game in the ents power business.

Might be worth scrounging up a loner thermographic camera and looking around the three phase arrangements for a suspicious hot spot?


Bring one phase up to a fairly high load and check that the phase to neutral voltages are reasonably sane for the other phases.

Failing that, dud batch of quartz gets my vote, spikes do not take out lamps (Or if they do there is usually lots of other smoking wreakage), and a surge sufficient to would be very obvious in all sorts of ways.


Re the codas, my bet is you will find that the contacts on the lamp holders are very pitted, known problem, fix is new holders AND new lamps (The pitted holder damages the lamp contact that then damages any holder it is put into, fun game), not a surprise in lanterns that old.


Regards, Dan.

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votage spikes takes out the filament, Manufacturing faults and hairline cracks coused by thermal and physical shock cause glass envelopes to explode. my guess is that the lamps are fakes... Id expect to "allways" be replacing lamps if I had 24 codas as houselights. Assuming thay are one for up to 12 hours a day, it will reach the notional 2k lifespan in about 6 months, divide that with the 24 fixtures and thats a lamp a week... Repalce a lamp nearly every week and in your mind it seems a frequent occurance in the same way that im sure I only just put those christmas lights into my loft...
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Thanks for all your responses,


After talking to the in-house guys a bit more their Codas are knackered copies (not strand) and the venue buys the cheapest lamps they can find so this seams normal to be replacing lamps all the time.


The exploding and failing lamps are all in the S4s I've got for the month all powered from the Art Rack, These are my concern. It's looking more like a fault with the Art rack, a floating neutral on the 125A3 or powerloc's would fry the whole rig so the fault must be within the rack?


Or I've got a whole lot of bad lamps which I think is unlikely, they are all from a highly reputable supplier.


I'll call the suppliers tomorrow... Am I right in thinking the modules in an Art rack can be interchanged on a job to job basis or is it a factory thing. Could some of the modules have a bad neutral?


Thanks again

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For a dud neutral to be causing this it must occur as part of a polyphase system, once things get broken down to single phase a dud neutral just causes darkness.


Bad batches of lamps happen to everyone, talk to your supplier, but apart from a possible neutral issue I do not see a dimmer fault being able to cause this.


Regards, Dan.

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