HMI striking trouble

[Shawn Nelson]

(sigh). Okay, so I bought a 2.5kw LTM HMI Par off of eBay to mess around with.

I followed the 'Set Lighting Technicians Book' and first installed my new bulb, then plugged in the header cable, then plugged in the ballast power then turned on both breakers, first the little one then the double one. Now what? I press the green button and nothing happens, at all.

Am I supposed to turn both breakers on or just one? I get power lights over the red button and on the orange light. Here is a picture of my ballast. What am I doing wrong?

And yes, I am feeding it 110v 30amps of power and it is a magnetic ballast.

 

[David Birdy]

Green button should light up...then just push...the pic shows this as an old device...is the E-bay seller reputable?

No Green light no High voltage.. Can you try a different bulb?

Dave

 

[Shawn Nelson]

Just got it working! Actually the green light didn't come on until the light struck. The problem was the UV indicator switch in the head was too recessed, it wasn't being activated. I pressed it in with my hand and noticed the red light on the head activated, I pressed the green 'strike' then jumped as the thing roared to life .

 

[Shawn Nelson]

Hmmm, so it's an older Mag ballast but still in good shape, fires right up and is very quiet. I then pulled out my Red and set it to 24fps and 1/48 shutter and 1/60 shutter. At both of them it seemed that I was seeing a TINY amount of strobing when looking at a white wall. Could this simply be the LCD interacting with the ambient light? Or do HMIs strobe a bit when it's a brand new bulb? Granted the strobing is very hard to see, at first glance there doesn't appear to be any and it's only visible to the LCD, to the eye it looks great.

 

[Mark Mannschreck]

You can see strobing problems more clearly by opening the P camera proxy and dragging the CTI through the timeline quickly back and forth.

 

[Nick Gardner]

Hi Shawn,

What are you powering the ballast from? Dryer plug or something similar? If you can put a freq meter on the power and check the Hz. Some times other things on the same circut can make mag ballasts flicker a little bit. Also try a different head cable. something close to 90% of HMI problems are head cable issues.

If you have a waveform, or a monitor with a wave form, flicker should be super easy to see when you shoot a white wall or card.

Good luck ,

Nick