Film-Tech Forum ARCHIVE: christie lamp won't ignite

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Posted by Warren Dewey (Member # 3609) on 01-19-2008, 01:52 AM:

I've searched the forum but not found this exact problem. I think I've lost my igniter, but not sure.

3 year old Christie SLC 40, New lamp. Changeover house, so I have a twin working lamphouse nearby to compare to.

At the start of the show tonight, lamp went out after 10 seconds or so, and won't restrike. Internal meter shows 40 volts with DC power switch on. (Usually runs at 25 V with lamp working.) Ready light is on.

Manual switch causes no jump in voltage on the meter. If I try to restrike with the manual switch more than once, the 3-phase breaker on the lamphouse pops. (The working lamphouse jumps to 40 volts or so when striking.)

I hear the relay when the dc power is switched on, but no hiss sound, which I usually hear when striking automatically. Manual switch makes the hiss sound, but still no light. So-- it looks like the igniter is bad--

However if I try to strike the lamp manually with DC power OFF, I get a momentary flash in the lamp. I can repeat this, but only after waiting a minute or so. It seems like the igniter is doing SOMETHING. Does this mean the igniter could be ok, or is it most sincerely dead?

Posted by Monte L Fullmer (Member # 2797) on 01-19-2008, 02:13 AM:

quote: Warren Dewey
At the start of the show tonight, lamp went out after 10 seconds or so, and won't restrike. Internal meter shows 40 volts with DC power switch on. (Usually runs at 25 V with lamp working.) Ready light is on.

When the rectifier is on before ignition, the voltmeter should be pegged over 130vdc. If you get this, your rectifier is okey.

quote: Warren Dewey
If I try to restrike with the manual switch more than once, the 3-phase breaker on the lamphouse pops. (The working lamphouse jumps to 40 volts or so when striking.)

..for you've taxed your rectifer with it popping that 3ph breaker. I would bet that you lost a diode with it shorting out in that diode bank down underneath.

quote:
I hear the relay when the dc power is switched on, but no hiss sound, which I usually hear when striking automatically. Manual switch makes the hiss sound, but still no light. So-- it looks like the igniter is bad--

SLC-40 consoles uses the IGA15M igniter, and the igniter is okey since you got the "hiss" meaning that the spark is jumping across the electrodes in the bulb, but no required 120vdc from the rectifier to keep the bulb lit on the initial startup.

quote: Warren Dewey
However if I try to strike the lamp manually with DC power OFF, I get a momentary flash in the lamp. I can repeat this, but only after waiting a minute or so. It seems like the igniter is doing SOMETHING. Does this mean the igniter could be ok, or is it most sincerely dead?

as mentioned above, I would say that the igniter is okey. But, if you really want to find out, either swap igniters from that other console, or if have one on spare, do the swapout - just make sure that those two wires are crossed on the terminal strip on top of the igniter, for if you don't you'll blow the igniter very quick.

Okey, here's the dumbest question of all: did you try another bulb? Sometimes new bulbs will crap out on you without giving you any notice that they are getting ready to die...and trust me, it isn't fun looking like an idiot when you bust a console apart looking for the complicated problem and finding a solution when right at the tip of your nose is the simple and obvious conclusion of how your problem began in the first place.which turns into a very easy fix.

Good luck - Monte

Posted by Tim Reed (Member # 137) on 01-19-2008, 02:50 AM:

One of the rectifier diodes is shorted, or the bulb just died.

Posted by Louis Bornwasser (Member # 3063) on 01-19-2008, 06:50 AM:

Bulb is OK; because the breaker kicked, I surely suspect the diode theory. Louis

Posted by Warren Dewey (Member # 3609) on 01-19-2008, 09:14 AM:

The first thing I did was replace the bulb-- no luck there.

quote:
Monte said: When the rectifier is on before ignition, the voltmeter should be pegged over 130vdc. If you get this, your rectifier is okey.

---Even my good lamphouse never reads that high-- 40V tops on the built-in meter. Of course the lamp fires before I can see the open circuit voltage.

EDIT-- Finally dug up an analog VOM and it shows all 3 normal diodes shorted -- I will replace them but I'm wondering if the cause may still be lurking around. Losing three at once seems kind of odd-- or is it?

Thanks guys for your help on this.

[ 01-19-2008, 11:52 AM: Message edited by: Warren Dewey ]

Posted by James Westbrook (Member # 3690) on 01-19-2008, 02:24 PM:

Warren,
Mulitple diodes going out is not as abnormal as you think. I've had this happen twice to my Rentecs. I find the first bad diode, change it and wonder "why is it still not working?" only to find another diode out, too. Both would be reverse (non forward) diodes.
Oddly, I seem to lose more reverse diodes than forwards...

Posted by Warren Dewey (Member # 3609) on 01-19-2008, 03:05 PM:

Found actually one bad forward diode. Now that it's opened up I can reach them and measure with better accuracy. Could they make these things any harder to take apart? Thanks again for everyone's help--

hello 6K reels.... movies will have intermissions tonight--

Posted by Tim Reed (Member # 137) on 01-19-2008, 05:43 PM:

Yes, they're not as bad as they used to be, though. The newer versions have the rectifier stack mounting bolts secured to the console frame, so you don't have to jack around needing a third hand when reinstalling them.

I keep a small supply of 1/4-20 nuts on hand, to add to the bolts in older units so I can lock them to the frame. This makes it a heck of a lot easier to service the stack in the future.

Good luck!

Posted by Mark Gulbrandsen (Member # 72) on 01-19-2008, 10:19 PM:

Best to replace them all at once or you may be back in there in a short time. I generally use either the SKN/SKR series by Semikron(Allied Electronics) which have a much higher current and PIV rating or just drill out the heatsinks and use the diodes that Christie uses in the 4kw unit. If youuse either doides rarely is there ever a failure again. BTW The Semikrons are available in either metric or American thread. Be sure to specify which one you want.

Mark

Posted by Tim Reed (Member # 137) on 01-20-2008, 12:03 AM:

Mark, do you have a URL for those, to order online?

Posted by Mark Gulbrandsen (Member # 72) on 01-20-2008, 07:22 AM:

Tim,

I'll post this on Monday for you.

Mark

Posted by Tim Reed (Member # 137) on 01-20-2008, 01:55 PM:

Great! Thanks, Mark.

Posted by Darryl Spicer (Member # 711) on 01-20-2008, 02:26 PM:

We keep a back up diode bank on hand. We just pull the bad one out and put the good one in and get it back on screen. We then replace all the diodes in the removed bank and place it back in the cabinet for future problems.

Posted by Warren Dewey (Member # 3609) on 01-20-2008, 03:41 PM:

The Christie literature is a little hard to decipher but the circuit diagram calls for part numbers: 150K60A and 150KR60A. Those part numbers are made by Vishay and mean 150 amps, 600 volts. However the parts list in the manual says 150 amps by 1000 volts. I ordered them from Allied anyway because they are probably right, and they were in stock:
vishay diode page

Allied also carries the heftier diodes Mark mentions, but had none in stock..

Posted by Mark Gulbrandsen (Member # 72) on 01-20-2008, 08:51 PM:

Then you already have the "big" Christie diodes in there. Failure is pretty rare on those. Be sure the fan underneath the heatsinks is in GWO. They have a tendency to get clogged with dust.

Mark

Posted by Warren Dewey (Member # 3609) on 01-23-2008, 12:32 AM:

Update-- The diode arrived from Allied, physically a little different from the existing ones, but installed fine. Now the open voltage reading slams the meter, as Monte described.

However, still no strike, no arc that I can see. I replaced this new but as yet unlit bulb with the known good new one. The igniter hissed a few times but seems to have given up. Now I can sometimes hear a relay click 4-5 times after switching DC on. My supplier thinks the igniter has finally died, so a replacement is on the way. Manual strike doesn't work either.

Is there anything else I should check?

Thanks again gentlemen, for all the good advice.

Posted by Tim Reed (Member # 137) on 01-23-2008, 12:43 AM:

Check to make sure the ignition pulse is not arcing to ground somewhere near the reflector, or to a wire near the igniter itself.

BE CAREFUL... you have to do this with the door(s) open and the safety switches defeated in order to see it.

Posted by Mark Gulbrandsen (Member # 72) on 01-23-2008, 08:01 AM:

Having the lights off helps greatly!!

MArk

Posted by Warren Dewey (Member # 3609) on 01-23-2008, 11:21 AM:

No arcing anywhere that I can see. There was the usual hiss / zap sound from the igniter when I had the bad diode and when I first tried to start up with the new diode-- but hiss is gone now. I just hear a series of about 5 relay clicks, then nothing.

Maybe the shorted diode affected the igniter, which then gradually died? (What in my old recording studio days we used to call a clusterf--k....)

Posted by Louis Bornwasser (Member # 3063) on 01-23-2008, 02:02 PM:

Try the new igniter.

BTW: inside the igniter is a transformer with only three wires: 2 are the primary, one is high voltage. There is the other secondary wire which is soldered to a mounting screw. Unfortunately that screw is insulated. It is a wonder it ever worked. The wire needs to be "grounded" so that there is a return path for the high voltage. Be careful not to pinch the primary wires; many come that way from the factory. Louis

Posted by Warren Dewey (Member # 3609) on 01-24-2008, 08:27 PM:

The new igniter did the trick, machine 2 is back on the air. Probably toasted the old igniter trying to start with no DC(?) Thanks again--