VL 1000 Lamps Blowing

[pete LD]

This week I have been programming for a tour up in York; I have 6 VL 1000s on the rig, the tungsten ones.

We had finished programming and 1 hour before the opening show in the afternoon 5 out of the 6 lamps blew all at the same time.

It seems odd and we can’t see why? All the generics on the rig are ok so that to me rules out a power spike or similar.

One of the local crew said that the show they had in the week before had 13 blow in one go at a different venue, and it was because all the attributes where at 0 which seems odd as this never happens as there are always pan/ tilt at about 50 so they point at the stage! But I looked through my cues and right at the top there is a cue that had nothing in it at all so maybe could have ran that and it blew all the lamps.

Has anyone come across this before? Or any more idea why this might have happened? I don’t want it to happen again on tour!

I would like to thank Stage LX who managed to get a box of lamps to us for before the start of the evening show and the crew at York theatre royal for relamping so quickly!!

Pete

[Oovis]

We had a show in recently which blew lamps like mad on tour before it reached us, and when it sat here for a couple of months.

 

Previously we've had VL1000s which worked happily and didn't blow lamps in the entire run of six months. It's strange...

 

All attributes a zero sounds like a red herring to me <_<

[woody74]

Highly doubtful, but it was the first thing that popped in my head:

 

Any chance they went out with 120v lamps instead of 240v?

 

-w

[Tomo]

Any chance they went out with 120v lamps instead of 240v?

Or even 230V lamps?

UK voltage can be as high as 250V, and 240V is common.

 

Overvolting lamps does cause radical reductions in lamp life.

- Some dimmers have built-in regulation to ensure the output doesn't go above 230V, but some don't. (And sometimes it's turned off even if the dimmer can do it)

 

I don't know if the VL1000 internal dimmer version has regulation, but I would guess that it does.

 

Alternatively you could just have been unlucky.

If the lamps were all changed at the same time and have been used in roughly the same way it's not outside the bounds of possibility.

[pete LD]

[quote name='Tomo' date='20 Mar 2008, 8:55 PM' post='218472']

Any chance they went out with 120v lamps instead of 240v?

Or even 230V lamps?

UK voltage can be as high as 250V, and 240V is common.

 

Overvolting lamps does cause radical reductions in lamp life.

- Some dimmers have built-in regulation to ensure the output doesn't go above 230V, but some don't. (And sometimes it's turned off even if the dimmer can do it)

 

I thought about over voltage but didnt have time to stick a meter in a socket!

 

The units are from stage lx so I cant imagine they would have had the wrong lamps!

 

The local dimmers are ADB euro dims if that makes any diffrance!

 

we did have 2 other lamps go in the previous 2 days but then 5 at the same time!

Pete

[boatman]

Here's a bit of lateral thinking.

 

A good few years ago I had six out of eight profiles blow their lamps all at once, as soon as they were brought up to full. Just prior to that we had noticed some minor flickering of the house lights, but had thought nothing of it. I had an oscilloscope in the car so I looked at the mains waveform and it was extremely ragged. The star of our panto group just happened to be an engineer with Scottish Hydro-Electric Board and was horrified to see the display. He followed it up the next day and it turned out to be a faulty three phase motor in a pump house at the local reservior some four miles away. It seems the aging filaments had simply shaken themselves to bits with the harmonics.

[ceecrb1]

Dodgy neutral?

 

We had catastrophic problems a few weeks back due to a badly installed 400A powerlock neutral.

basically huge voltage ballancing problems on 2 of the 3 phases (one with 160 and one with 320V).

Possibly a less catastrophic version of the same problem.

It was nothing more than the screws hadnt been tightned up properly inside the connector!

 

I learned a butt-load from this experience about the importance of a good incommer.. you learn things the hard way, and I learned this on the 36hour shift I did at the last minute to repair everything that fried on the 320V phase!!!!

[Wuddy]

What brand were your lamps? I had a big problem with a batch of Phillips lamps in standard fresnels and profiles last year, The slightest mechanical shock, undoing the yoke locking nut and the lamps blew.

[David Buffham]

Is it possible that the fixtures were re-calibrated or power-cycled whilst the lamps were on? The VL1000 calibration routine is quite rough with a lot of mechanical juddering, so I would think there would be an increased likelihood of tungsten lamps blowing if they were on during the calibration. This probably wasn't the case in this incident, but I personally wouldn't reset a tungsten VL1000 with the lamp on.

 

With regards to the type of lamp, there's only 1 type of 240V tungsten lamp that Vari-lite approve for use in VL1000s (Ushio) - see here

[Caldair]

The reason for several going at the same time could be, IIRC, that when the first goes there's a spike on the grid that could take out another one, and another, and another...

 

Black Box Theatre in Oslo has a form for visiting companies asking if they use pyrotechnics, water etc... or flour. It's because they had a play once that used a lot of flour on stage, it got into the fixtures and coated the bulbs, allowing very little heat to escape... Took them a while to figure out why their lights kept dying.

Probably nothing to do with your case at all, I just thought I'd share. :P