Film-Tech Forum ARCHIVE: Re-striking a xenon bulb

This is topic Re-striking a xenon bulb in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ken Lackner (Member # 1002) on 11-21-2003, 02:58 AM:

It is my understanding that a xenon bulb can strike at any state of cooling, that once it goes out you do not have to wait for it to cool down before you can strike it again. We had a show stop for a moment today and when we started it again the bulb would not strike. We had to wait nearly five minutes before we could strike it again. What could cause this? It is a Xenex II lamphouse with a Kni-Tron power supply. We use a mix of Christie and Osram. Not sure which one is in this house.

Posted by Howard Johnson (Member # 62) on 11-21-2003, 04:25 AM:

I tend to leave the xenon on unless there is a break of an hour. Every time you strike them it puts the eqivalent of perhaps 15 mins time on them - I'm not sure of exact time. I've found that different lamphouses vary in whether they will be difficult to restart after a short interval. It's easier to leave them on!

Posted by Chris Greenwell (Member # 1660) on 11-21-2003, 04:31 AM:

I had a power bump a few days ago, just enough to stop the machines. My older bulbs had a hell of a time striking back on, but the new ones striked right back up.

Posted by Joe Beres (Member # 678) on 11-21-2003, 08:24 AM:

I too have found striking, and especially re-striking a warm lamp, more difficult with an older lamps. Does it take a while for the initial strike at the beginning of the day? How many hours on the lamp?

Posted by Antonio Marcheselli (Member # 373) on 11-21-2003, 08:34 AM:

I worked in a theater that had many problems striking hot lamps. But the lamphouse had definively some problems since all the time the 4000 lamp was black after 4/500 hours.

Bye
A

Posted by Jeff Taylor (Member # 443) on 11-21-2003, 09:06 AM:

In theory a xenon lamp will re-strike at any temperature, but hot re-strikes are more challenging than cold strikes. There are several reasons for this, but the main one is that xenons are tougher to strike as the pressure inside the lamp increases. Different manufacturers pressurize their lamps to different levels at the factory to begin with, and there is a correlation between pressure and the quality of light output. Similarly, the hotter the lamp is the higher the pressure, which can lead to the hot re-striking problem. Also, as the hours pile up on a xenon lamp the electrodes naturally wear causing the gap to increase and making striking more difficult. Then there's the whole issue of ignitor voltage and run amperage which can cause more problems. If everything is running up to spec and your lamp is relatively new you should be able to re-strike hot, but it's not surprising that in a real world situation you might have problems, or at least have to zap it a few times to get a strike while hot.

Posted by Darryl Spicer (Member # 711) on 11-21-2003, 09:07 AM:

I used to work with Xenex II lamphouses year ago. This was a common problem with those. What they did was change the igniter to one that was used in a stong lamphouse. Problem never occured again.

Posted by Ian Price (Member # 14) on 11-21-2003, 11:41 AM:

We had a problem re-striking a hot lamp in our big house. It has a Strong Highlight, switching power supply and a Christie lamp. Since I have worked in many theatres with many size lamps, I knew that it was not the lamp. Indeed, eventually the power supply failed and was replaced. Now there is no problem, ergo it may be a power supply problem.

Posted by Daryl C. W. O'Shea (Member # 1303) on 11-21-2003, 11:55 AM:

Power supplies with lower no-load voltages will have problems starting hot lamps.

Posted by Ken Lackner (Member # 1002) on 11-21-2003, 02:02 PM:

No we do not have any problems with a cold strike in this house. Not sure how many hours are on the bulb, but it's a safe bet that it needs replacing. And if the show has stopped because the automation stopped it, the bulb will go out. No way to keep it on.

Posted by Travis Hubrig (Member # 1745) on 11-21-2003, 09:18 PM:

I run 7 Xetron XHN's, never had a problem with a hot bulb striking. I run Osram 1600 w bulbs and the few problems I encounter are due to improper cooling.

Posted by Brad Miller (Member # 2) on 11-21-2003, 09:26 PM:

I'm curious as to what kind of lamps most of you with problems are using and what kind of systems you are using them in. For instance, you can sit there all day long at 5 second intervals and fire / extinguish / fire / extinguish / fire / extinguish a Christie lamp in an SLC style Christie console (not the older ones though). The same thing can be said for a Christie lamp in a Strong lamphouse with a switcher power supply (at least my 2K units can), and I've never had a glitch from a Christie lamp in a Cinemeccanica lamphouse with Irem supply either. The only time I have ever had issues like this is with high reactance Strong supplies and non-Christie lamps.

BTW, a tip I picked up awhile back that does work nicely. If you have a bulb past it's warranty hours and it is having issues striking and you do not have a spare handy for replacement, up the tap settings one notch for one show, then put them back. I've had lamps run another 3 months without a hint of problem after doing that. (Disclaimer - check with your service tech before doing this. It is ultimately his/her decision.)

Posted by Dave Callaghan (Member # 1544) on 11-21-2003, 09:48 PM:

According to an OSRAM publication, increasing the current is discussed in connection with bulb rotation.

After a rotation, OSRAM suggests operating the bulb at its current control range maximum to re-establish the arc root at the cathode tip to reduce arc instability / flicker.

When a horizontal bulb has just been rotated, OSRAM recommends operating the lamp for 30 minutes to 2 hours at the permitted maximum current to reform the cathode root.

Posted by Travis Hubrig (Member # 1745) on 11-21-2003, 10:09 PM:

I have been told, and maybe have read it here, that bulb rotation in a horizontal installation isn't necessary anymore.
The material and technology in the bulb is getting better and the deposit on the quartz isn't nearly as bad as it used to be.
Most of my bulbs never get rotated.

Posted by John Pytlak (Member # 331) on 11-21-2003, 10:12 PM:

Lamp rotation should be per the lamp manufacturer's recommendation.

Posted by Per Hauberg (Member # 529) on 11-22-2003, 08:01 PM:

On my new FP30D with Kinoton 700/2000 lamphouse, I was a bit disappointed, finding that the lamp has no manual dowser (or what is the correct word in english), only the c/o dowser, which is so small that it allows a bit of light to get around it - just enough to let You see the numbers of the leader on a dark screen. The automation is therefore born, so that the lamp can not stay turned on, when projector is not running. Lamp is ignited and turned off with every motor start/stop, unless You cut off the power (when treading film, etc.) I have always learned, that every ignition cots 15-20 minutes of the lamp's life, and do not find this good. Also, -now I have for the first time ever, a projector with a bit of automation, -I would like to use it to have my hands free for scratching, nosepicking and other duties, but I have to hold one hand in front of lens, to keep those darn numbers away from screen. Are these (otherwise great) lamphouses from Kinoton not equipped with proper closing devices, when installed for bigger lamps than my 700 watt, either ?

Per

Posted by Richard Fowler (Member # 893) on 11-23-2003, 06:24 PM:

ahhhhh....the manual douser is an option. Kinoton is like our hamburger food chain...Burger King..which you can have your burger any way you want....you just have to ask for the pickle ( manual douser ) [Big Grin]

Posted by Per Hauberg (Member # 529) on 11-23-2003, 07:50 PM:

Richard:

Of course, one always want the best possible price on new equipment, but...
well, -i'd better ask, if they've got a glass of pickles left down there...

p

Posted by System Notices (Member # 2357) on 05-15-2005, 01:02 PM:

It has been 538 days since the last post.

Posted by Brad Allen (Member # 470) on 05-15-2005, 01:02 PM:

quote: Darryl Spicer
I used to work with Xenex II lamphouses year ago. This was a common problem with those. What they did was change the igniter to one that was used in a stong lamphouse. Problem never occured again

What would be involved in replacing the ignitor in a Xenex 1 L2000 lamphouse with a Strong or other recommended ignitor?

Posted by Brad Allen (Member # 470) on 05-16-2005, 09:03 PM:

Anyone?

Posted by Mark Gulbrandsen (Member # 72) on 05-16-2005, 10:09 PM:

Brad,
What for? The Kneisley ignitor is not all that bad... pretty reliable, although a tad noisy like a Super Lume-Ex. I've only repaired two in over 25 years. Both of those were repaired and then put back in place and are still working today. I don't think Strong has nearly as good a track record as Kneisley in the ignitor departmment. I have installed LP ignitors in Xetrons due to the high cost of the replacement IREM units though.
Basically, any ignitor designed to work at the negative end of the lamp should work though.

Mark

Posted by Richard Fowler (Member # 893) on 05-17-2005, 10:30 AM:

The Kneisley ignitor was also designed to withstand the infared heat coming out the rear of the glass reflector. Very rare problems with their ignitor....most problems are on the autostrike relay board or start switch which are away from the ignitor. The weak point is the wiring connection to the main coil to the negative bulb attachment...the coil can rotate slighty when loosening the connection to the bulb lead and flex the wiring....just hold on the coil when tighting / loosening the stud + nut.

Posted by Brad Allen (Member # 470) on 05-17-2005, 11:52 AM:

I'm just grasping at straws, trying to cure a couple of on going issues with my Xenex 1's.

I had seen mention of the Kniesley ignitor being "noisy". I took that to mean it was electrically noisy, I'm still trying to cure the problem when starting Projector C, when the lamp ignites, it cause's the TA-10 on Projector B to go into "intermission".

I'm doing the Grainger blower upgrade soon (been ordered) on the lamphouse's, hoping that cures the hot bulb starting problems. Another of my reasoning for possibly replacing the ignitor with another brand. And at times, we have problems with starting cold bulbs.

Wow, "Betty at that extension" can really get testy when you call and ask questions that make her think your being critical of "her" equipment. All I did was ask to speak to someone who could tell me the correct wiring for the new autostrike boards? [Big Grin]

"All our equipment comes with instructions"....Uh, these didn't Betty. [Big Grin]

It was funny.

Comments appreciated.

Posted by Mark Gulbrandsen (Member # 72) on 05-17-2005, 10:46 PM:

quote: Brad Allen
I'm still trying to cure the problem when starting Projector C, when the lamp ignites, it cause's the TA-10 on Projector B to go into "intermission".

Brad,
The problem is the TA-10. Really a dinosaur of an automation and it is pretty susceptabale to ignition noise. I quit using them after about the 3rd unit. The EPRAD ultimation and Strong units are basically immune to noise... just as a comparison of automations. EPRADS father company, TL Industries, designs and builds computer controled robotic controllers for the auto industry and they have extensive experince with controllers being used in noisy areas. You can also try bypassing the AC lines with some caps and see if this helps out. Bypasas at both the automation and at the lamaphouse. Whaht might actually work here is just a simnple CORCOM ac line filter. These are available form places like Allied Radio. go to www.corcom.com Check out the B series filters on the products page.

Probably the quietest ignitor out there is the old LUM-EX unit. All you hear is a little tick from it. Why Strong quit making that design is beyond me.

Good luck with the blowers. Won't help the noise much but it will give much longer lamp life anad generate some different noise. Again, be sure to check the rotation direction after assembly..... there is a huge differece in suction.

Mark

Posted by Richard Fowler (Member # 893) on 05-18-2005, 09:02 AM:

The brute force design of the Kneisley tends to make it noisy. In addition to Mark's good tips, Component Engineering has a shield kit for RF problems that you are experiencing for the TA10.

Posted by Brad Allen (Member # 470) on 05-19-2005, 03:51 PM:

Mark, Yesterday I installed a Tripp-Lite surge protector on both offending TA-10's. Unit includes RFI and EMI filtering. If this doesn't help, I will try the part you suggested.

I also discovered yesterday, that the conduit for the DC wires from the P.S. to the lamphouse on the offending lamphouse, was watertight type & did not have any metal in it, so no RF shielding. I replaced with metal flex.

Richard, I knew Component Eng. had the RF shield kit, but I thought it was only for the drawer mount. Will it work/fit in my Wall mount units?

I just thought, I don't have the cable that goes from the FM-35 to the TA-10 in flex conduit, should I. I assume this would be a source of picking up RF?

Thanks for the suggestions guys, much appreciated. [beer]

Posted by Richard Fowler (Member # 893) on 05-19-2005, 05:08 PM:

I have used the shield unit on TA-10 wall mounts.

Posted by Marin Zorica (Member # 1716) on 05-23-2005, 10:09 AM:

I didn't have any problems with striking a hot lamp with most equipment what is in use, but i have with new equipment, because rectifier i use have 95-120V no load voltage!!!!!!

So for that isn't hard to strike bulb even after 2 hours working!

Also igniter have around 45KV ignition voltage!

But with new equipment i had some problems because some new rectifier have 75-80V no load voltage (what is low if you ask me!).

What is with vertical bulb rotation?

How often must be rotated and how much in degrees?

Posted by Brad Allen (Member # 470) on 05-26-2005, 02:49 PM:

Ok, to update this, I installed two Tripp_lite surge suppressors on both TA-10's. These also filter RFI/EMI. At the same time I replaced the water tight conduit from the rectifier to lamphouse with BX flex. One of the two things cured the problem. It's been a week now, and nary a hiccup out of either the TA-10s. [Smile]

Posted by Mark Gulbrandsen (Member # 72) on 05-28-2005, 11:02 AM:

Excellent Brad!