Film-Tech Forum ARCHIVE: Ignitor Problem

This is topic Ignitor Problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Martin McCaffery (Member # 37) on 08-11-2007, 08:11 PM:

Strong 60XD, Christie XM rectifier.

Lamp won't ingnite. No arc. Getting a slightly audible hiss from inside the lamphouse when using the emergency ingnitor button. Bulb has only 500hrs and no visible signs of problems. Have not tried switching it out yet.

All safety switches and internal fans running and indicator lights lit.

Have I just lost my ignitor?

Posted by Mark Gulbrandsen (Member # 72) on 08-11-2007, 08:28 PM:

If the lamp looks normal probably yes. In an energency use a cattle prod to ignite the lamp.

Mark

Posted by Michael Schaffer (Member # 1204) on 08-12-2007, 01:04 AM:

Are you kidding, Mark?

Posted by Leo Enticknap (Member # 534) on 08-12-2007, 03:14 AM:

And even if you're not, how many projection booths just happen to have the odd electric cattle prod lying around in the tool cupboard?!

Posted by Stephen Furley (Member # 1277) on 08-12-2007, 04:45 AM:

quote: Martin McCaffery
Getting a slightly audible hiss from inside the lamphouse when using the emergency ingnitor button.

That sounds like the ignitor is working; are you sure that the main d.c. supply is getting to the lamp ok?

I had a lamp that wouldn't strike a few months ago, if I pressed the ingition button I could hear it, as you describe, and through a small hole in the bottom of the lamphouse I could actually see a dim spot of light on the floor from the ignition sparks. Are there any holes in your lamphouse where you could see this?

In my case it turned out to be no three phase supply to the rectifier, breaker tripped in the main distribution panel. Irem rectifier, had no indication of incoming supply being healthy.

Posted by Dustin Mitchell (Member # 372) on 08-12-2007, 06:32 AM:

quote:
And even if you're not, how many projection booths just happen to have the odd electric cattle prod lying around in the tool cupboard?!

Some chains have resorted to rather unorthodox crowd control techniques....

Posted by Martin McCaffery (Member # 37) on 08-12-2007, 11:51 AM:

quote: Stephen Furley
That sounds like the ignitor is working; are you sure that the main d.c. supply is getting to the lamp ok?

Power in coming in fine. No little light as far as I can tell. Also not getting the thump we usually get on ignition.

As for the cattle prod, wouldn't a taser be more convenient? [Wink]

Posted by Stephen Furley (Member # 1277) on 08-12-2007, 12:25 PM:

quote: Martin McCaffery
Power in coming in fine. No little light as far as I can tell. Also not getting the thump we usually get on ignition.

Do you mean that a.c. power is coming in to the rectifier, or d.c. power is coming in to the lamphouse? The 'thump' sounds like a contactor; if that isn't working for some reason then you wouldn't be getting any power to the lamp. I don't think it's an ignitor problem; it sounds more like either a faulty cotactor, or whatever is operating it, switch, relay etc.

Posted by John Hawkinson (Member # 1135) on 08-12-2007, 02:53 PM:

Cattle prod: 9kV
Xenon lamp ignition: 20-50kV
Taser: 200-300kV

Posted by Monte L Fullmer (Member # 2797) on 08-12-2007, 07:44 PM:

Push down voltage switch (or, put a VOM meter across the lamp leads coming out of the rectifier with the VOM on DC settings) then turn rectifier on and before pressing ignition. If voltage doesn't swing up past 130VDC before ignition, then, recifier has gone kaput, or the contactor for the incoming 3ph current isn't making the clean connections when closing - the ignitor is fine.

This is the most common results of ignition failure and most blame the ignitor for failure in bulb ignition.

Posted by John Hawkinson (Member # 1135) on 08-12-2007, 08:22 PM:

WARNING:

DO NOT attempt to strike the bulb (manually or autostrike) with a VOM connected. You will destroy your meter with the high-voltage pulse.

--jhawk

Posted by Monte L Fullmer (Member # 2797) on 08-13-2007, 03:41 AM:

(ain't that the truth - found that one out the hard way the one and only time..luckilly it just knocked out the fuse inside)

Forgot to say, if using a VOM, run the test leads before the ignitor - preferably at the output of the diode bank where the heavy bulb leads are attached.

Posted by Kenneth Wuepper (Member # 1174) on 08-13-2007, 06:34 AM:

Whenever testing the power supply to a lamp, disable the ignitor by removing the fuse or disconnecting one of the supply leads to the unit. If the voltage were to reach the triggering level for ignition while you are making the measurement, the ignitor could engage and destroy the meter. There is enough high frequency energy on the rectifier leads to destroy a meter, even at the output terminals of the power supply.

Remember, you may think you are smarter than the electricity but you are way slower!

KEN [Eek!]

Posted by Mark Gulbrandsen (Member # 72) on 08-13-2007, 08:11 AM:

quote: Michael Schaffer
Are you kidding, Mark?

quote:
And even if you're not, how many projection booths just happen to have the odd electric cattle prod lying around in the tool cupboard?!

No, not kidding! I learned this from an old RCA tech in Chicago many years back. It does work. They are pretty easy to find at any country store or feed supply.

Mark

Posted by Stephen Furley (Member # 1277) on 08-13-2007, 08:27 AM:

I've sometimes been able to start an old mercury or SOX (low pressure sodium) lamp that's near the end of it's life and not been used for a long time by giving it a bright flash of light from a flashgun. With difficult SOX lamps if you start them by this means and then let them run for a few hours they will usually start by normal means after they have been switched off.

[ 08-13-2007, 11:01 AM: Message edited by: Stephen Furley ]

Posted by Louis Bornwasser (Member # 3063) on 08-13-2007, 08:57 AM:

Once had a regular Lumex that would not try to ignite when voltage was low (190v instead of 208v). This lamp did not have any form of manual ignition.

Plugging in a Weller soldering gun to the same phase and clicking madly sent enough spike to trigger the triac to conduct. Worked on all four lamphouses until voltage could be corrected. Louis

Posted by Martin McCaffery (Member # 37) on 08-13-2007, 12:14 PM:

And the winner in:
Burned through contact nut on the terminal board for the rectifier tap switch. due to dim booth light and that it stayed in place, wasn't noticable when I opened the rectifier originally. When I moved the front panel of the rectifier, it popped right out. Per Louis suggestion (on the phone, not the thing about the soldering iron) I moved the tap switch down a step and the lamp ignigted.
So we will be a little dim on one projector until we can get the board replaced, but no more potty break for the audience at the reel change (though they are old and kinda like the break).

Thanks for the suggestions

Posted by John Hawkinson (Member # 1135) on 08-13-2007, 01:09 PM:

Alright, I'll bite. Mark, how exactly do you use the cattle prod? To the two terminals for the spark gap? Or...?

--jhawk

Posted by Mark Gulbrandsen (Member # 72) on 08-13-2007, 02:17 PM:

Just touch it to the nichrome wire that is arond the globe and it'll ionize the gas enough to iginte the lamp.

Mark

Posted by Michael Schaffer (Member # 1204) on 08-13-2007, 05:02 PM:

quote: Mark Gulbrandsen
No, not kidding! I learned this from an old RCA tech in Chicago many years back. It does work. They are pretty easy to find at any country store or feed supply.

Hard to picture since the voltage given off by these appears to be well below what is needed to fire the spark across the gap, but since I haven't tried it myself, I have no basis for doubting your story. Still, that may not be a good idea to recommend doing to a projectionist who may end up zapping himself with the equipment... Did you make special leads for that, and where did you attach them?

EDIT - OK, I see you answered that question in the meantime. So in that case, did you start the power supply, open up the lamp house (after bridging the door switch) and zapped the lamp through the nichrome wire? While wearing a welding mask?

Posted by Louis Bornwasser (Member # 3063) on 08-14-2007, 11:22 AM:

1. Great way to get rid of someone you don't care for.

2. It may solve two problems. (see above)

It probably will work, since there are no losses (cable, capacitance-to-ground, cable twists & turns.) Louis

Posted by Michael Schaffer (Member # 1204) on 08-16-2007, 01:58 AM:

quote: Mark Gulbrandsen
Just touch it to the nichrome wire that is arond the globe and it'll ionize the gas enough to iginte the lamp.

Wouldn't that short the cattle prod to hell? Or are these short protected?

Posted by Mark Gulbrandsen (Member # 72) on 08-16-2007, 07:48 AM:

Michael,

You ought to get one and play with it... they are available on E-Bay.

Mark

Posted by Michael Schaffer (Member # 1204) on 08-16-2007, 04:49 PM:

That doesn't answer my question. But I will get one and try it on you at ShoWest next year. I am sure Brad will want to film that. [Wink]

Posted by Louis Bornwasser (Member # 3063) on 08-16-2007, 08:48 PM:

Michael; I seriously doubt that Mark will "light." Louis

Posted by John Hawkinson (Member # 1135) on 08-16-2007, 08:49 PM:

It's because somebody snipped off the nichrome wire a few years ago...

--jhawk

Posted by Leo Enticknap (Member # 534) on 08-17-2007, 06:12 PM:

Isn't there a story on Darwin Awards somewhere about a bloke who, after the electric igniter on his gas cooker failed, tried to light the hob with an electric cattle prod? If I remember correctly he'd left the gas on while he went to get the prod, and by the time he returned to the kitchen and tried it the build up of gas was sufficient to blow up the whole house (and him with it). I've tried searching on the site but can't find it. Not in quite the same league as the teenage Star Wars geeks who attempted to build DIY 'light sabres' by removing the end caps from fluorescent light tubes and filling them with petrol, but satisfying nonetheless...