Film-Tech Forum ARCHIVE: Bulb ignition Problem.

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

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Posted by Jack Culpepper (Member # 724) on 01-26-2004, 11:16 AM:

I have just had my ORC 2500 Lamphouse and rectifier refurbished. It now seems to be working perfectly. It pulls the required 55 - 70 amps. Screen and image brightnes are perfect. The problem is that I have CANRAD-HANOVIA 1600 watt bulb that is starting to darken. I figured its time to replace the bulb. I bought an OSRAM 1600 Watt HS-OFR bulb. I replaced the old canrad-hanovia bulb with the new bulb and turned on the lamphouse. Nothing happens. The new bulb will not ignite. I put the old bulb back in and everything works perfectly. The old bulb ignites as it should. I have gone through this process a number of times and with three new bulbs each time. BOTTOM LINE; The old bulb ignites as it should and the new osram bulbs do not. ANY IDEAS AND/OR HELP WOULD BE GREATLY APPRECIATED.

Posted by Rick Long Jr (Member # 541) on 01-26-2004, 11:50 AM:

Weird.
Is it just sitting there dead, or is the ignitor firing? if so, it could be that the new bulb is positioned too far back in the reflector and the spark is jumping to groung. Try adjusting the bulb focus control all the way one way or another. It could be that the end caps are different enough between the bulbs that this could be the cause.

Posted by Paul G. Thompson (Member # 655) on 01-26-2004, 07:27 PM:

You probably got an Osram that was Dead On Arrival. Seen it happen.

Posted by Gordon McLeod (Member # 33) on 01-26-2004, 07:32 PM:

Still the ignitor should attempt to fire
One of the things I see a lot of is it didn't work or didn't light being used a few more details really should be added always such as ignitor attempted to fire (heard spark gap ) no flash in lamp and it didn't light or similar

Posted by Jean-Michel Grin (Member # 1360) on 01-30-2004, 05:07 PM:

Do you use an "automatic" DC Igniter ? Maybe the No Load voltage is too low.. It's happend to me with a hight reactance Strong's rectifier.

Posted by Matt Zeiner (Member # 1914) on 01-30-2004, 07:04 PM:

the 2500 has integral rectifier, no? I beleive there is a separate boost circuit to jack the no-load voltage up - have found open resistors in there, but this is something else most likely. are the bulb ends making good contact? try jumping out the microswitch that closes when the lid is put on...very strange indeed.

Posted by Darryl Spicer (Member # 711) on 01-30-2004, 07:11 PM:

Well, I would think that the bulb should be good. If it wasn't there would still be a spark across the gap. Maybe the igniter is not putting out enough voltage to Send a spark across the gap. Sort of strange situation but I would check and make sure that the voltage is pegging above 100VDC.