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ballast compatibility question

hmi ballast header cable

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#1 Brian McCann

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Posted 02 June 2013 - 09:51 AM

So a while back I bought a used desisti 1.2 hmi fresnel paired with a lightmaker electronic ballast off ebay. I asked around before buying to see if it was a good idea and people I trust seemed to think so. Not long after buying I learned that these lightmaker ballasts have a really bad reputation. I've been using the light and so far no problems. I'm paranoid that it will die on a shoot. This would be really bad because often this is the kind of light that creates the ambiance of the scene and it's impossible to replace with a different light if it dies and could screw up a production. I am thinking of getting a magnetic ballast as a cheap and reliable alternative.

Does this make sense?

Also will I have to re-fit the header cable in order for it to work or is it possible the connector will be the same? I'll include pictures of the ballast I own and one I would potentially buy.

 

one I own is on bottom

 

ballasts.jpg

 

 


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#2 Edward Lawrence Conley III

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Posted 03 June 2013 - 12:24 PM

The problem with Light Maker is that once it does go down, parts are hard to come by.


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#3 Brian McCann

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Posted 03 June 2013 - 07:21 PM

Yeah I talked with one repair guy here on the east coast and he said he won't even touch them. 


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#4 timHealy

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Posted 09 June 2013 - 01:31 PM

I wouldn't buy any used HMI light ever! You don't know how they were treated or taken care of. They are complicated mechanical/optical/electrical devices tossed around on trucks, shelves and carts by teamsters and electricians of all sorts of skills. Having said that, I would never use a light maker ballast ever! They sucked when they were new. If you insist on having light maker ballasts, get an arri square wave or spare magnetic ballast. My first experience using them years ago was one of my worst experiences as an electrician were they were failing over and over again all night. Maybe an electrician who has HMI ballast repair experience can keep them going, but not the average joe.

 

best

 

Tim


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#5 Leonardo Brocato

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Posted 09 June 2013 - 06:18 PM

I'm from europe.....we use a lot of DeSisti but we don't have lightmakers.
The head connector is easy to change, ovviously the connector on the ballast not the one on the cable that is factory connected....
Here in italy connectors are different, Arri and Powergems has one  and Desisti another, but the pins are the same, so if you mark them you can easily change and recable....in therms of qualily i really don't know, but in my experience Arri are 10, new desisti are 5 with problems of flicking at extreme shutters like 45° and power gems are cheaper with a lot of problems....

Hmi are a strange equilibrium of ballast, Bulb age and input frequency, just think about the fact that a virgin hmi bulb takes at least 2 hours of work to go on the °Ktemp declared (6000 °k) due to the chemycal stabilization of the elements and rare hearts the frist striking is about 10000 °k

So try the ballst with the fixture and a good bulb, but this can't avoid future electronic or electric failiure of the unit.
Change elements on a ballast can be easy if you can really see what is the problem (burned or broken connector or parts) if it's an invisible probelm you need an expert....but a real one.
Another question is that i'm not sure if the electronic part of the head can properly work with a lightmaker ballast, properly means that you can strike it but the factory standards are not garanteed, like brilliance hot restrike or dimming but also color temp and power factor, uh, does the lightmaker ballast has a high power factor? (must be written on it volt,ampere,watt and power factor expressed in cos of greek letter Fi)

I hope you can understand my italian/tecnical/english

I agree with Tim for a beautiful, Arri square wave magnetic ballast heavy like stone, you can also uses instead of sandbags

good luck

 

Leonardo Brocato
Gaffer Rome Italy


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#6 Jason Fratis

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Posted 23 June 2013 - 02:32 PM

The ballast is the real heart of the system.  I always buy new ballasts but heads can be used.  Have spare ignitors and everything else is pretty easy to deal with.  Having spare ballasts is always a good idea.  I use power-to-light ballasts and so far not one problem in several years.  You can basically make any ballast work with any head.  I have LTM, Mole, Arri heads and all work off the same ballasts.  You can either make adapters or unify the connectors and pin configurations.  Im using Mole/Cinemills and have converted all to that.  I also make all my own head feeders.  This is crucial.  It doesnt wind up cheaper, but this is one area you dont want failure because its so easy to keep from happening.  If a ballast goes because of an internal failure then at some point that cant be helped.  If it goes because you had a head feeder failure, that is avoidable, that it a terrible feeling.  More often then not people dont even want to open a connector and look inside.  This practice is scary.  If you havent inspected your feeders then do so before using again.  Do get a spare.  I suggest a new PTL ballast and use the one you have as the spare.


Edited by Jason Fratis, 23 June 2013 - 02:35 PM.

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#7 Phil Rhodes

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Posted 23 June 2013 - 06:31 PM

I once spent some time at about 3 in the morning the day before a shoot re-terminating an HMI feeder...


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