This is topic Osram 7K Bulb Woes in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Rick Long Jr (Member # 541) on 07-27-2001, 08:54 PM:
Is anyone else having trouble with the Osram 7000 W/HS Lamps in Strong consoles? We have a couple of screens at different theatres that consistently give us trouble. Sometimes a brand new bulb will refuse to light, while others fail after as little as 20 hours. No load voltage is not a problem (in excess of 130V) and the D.C. pulse ignitor is pulsing. You can hear it trying if you put your ear up to the side of the lamp(tick,tick,tick,), though if you open the door a crack fast enough(with the mask on of course) I can see the arc sort of "fanning out around the negative end of the quartz envelope to the nichrome wire, but no further. The kicker is a 4k bulb will strike up first time every time. The ignitors have the new and "improved" style pc boards. Mains voltage is 117 from each leg to neutral(205V 3Ph.) Could it be that the gap between the 7K's electrodes are too wide for the voltage created by the ignitor?(Or right on the edge?) Its so bad in some theatres that the "highly trained" booth personell prestrike up to 30 minutes prior to showtime, which has resulted in both toasted ignitors and toasted changeover blades when they do light, and sometimes they do light just fine. Any insight would be greatly appreciated. Thanks!
-RICK!-
Posted by Dave Macaulay (Member # 813) on 07-28-2001, 10:41 AM:
A certain chain in Canada has had the same problem, but only on the switching supplies. They have changed to high reactance on all 7K houses, as well as using the "new" ignitor boards. (they also use only high reactance supplies on new projects now as far as I know)
The retrofits use permament AC wiring but with the MS output connector and they leave the AC plug attached to the console, so they can carry a removed switcher over and get back on screen in a few minutes if a diode fails.
I don't know if you have the switchers, but it's odd that the pulse ignitor does OK with a passive rectifier for them. I still like the tesla coil ones a lot more anyway. They still buy quite a few pulse ignitor boards so they must be giving some trouble.
Posted by Rick Long Jr (Member # 541) on 07-30-2001, 08:35 PM:
The theatres with the problems use switchers. I am starting to think it must have something to do with the ignitors. We also run Osram 7K bulbs at a drive-in in Cinemeccanica X-6500 lamps with big old DX-4 tesla type ignitors and there has never been a problem. As for the rectifiers, they strike up a 4 or an ORC 6500 just great. Maybe I'll try an older ignitor, if I can find one with a secondary coil beefy enough. Thanks!
-RICK!-
Posted by Tim Sherman (Member # 569) on 07-31-2001, 01:09 AM:
Do the Osram bulbs require more power to ignight then most xenon lamps? I have an ORC model 6,000 lamphouse with the RPS-X60 rectifier. I have never tried using an Osram lamp, but i have for that lamphouse/rectifier a little booster box that says on the label for osram 6k xenon lamp. It was made by orc for that model rectifier. So my question is what is it? and what is the need for this with only an osram lamp? i see nothing about it in the manual. The little box weighs a bit so i assume it has a transformer in it. I don't have the model number here but i can get it if that would help or be of interest to someone.------------------
http://www.autoramadrivein.com
come on out to the drive-in and spend a night out with the stars"
ME!!
Posted by Rick Long Jr (Member # 541) on 07-31-2001, 07:58 PM:
Hmmm. Ive never heard of that before. How does this box connect? Does it connect to the big D.C. lines or to the lamp control. Since most ignitors use the no-load voltage from the rectifier to fire them I doubt it does anything to the rectifier since there is already enough juice to fire it without the box. Perhaps it increases the output voltage of the ignitor? Anyone else ever heard of this?
Posted by Tim Sherman (Member # 569) on 08-01-2001, 12:56 AM:
Tomorrow night i will get the model number and all the other information off of this mysterious box i have. There isn't a plug on it just spade connectors.------------------
http://www.autoramadrivein.com
come on out to the drive-in and spend a night out with the stars"
ME!!
Posted by Gordon McLeod (Member # 33) on 08-01-2001, 11:46 AM:
There were two fixes for the low noload voltage issue one was a add on box the other for the XPS45 was a timed relay switching the input taps