Film-Tech Forum ARCHIVE: Lamp intermittent out 5 sec

This is topic Lamp intermittent out 5 sec in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=003459

Posted by Jan Hackett (Member # 1231) on 05-18-2002, 10:57 AM:

7 kwatt 150amps current maxed ,,Strong highlight II console. bulb warranty 600 hrs...actual 645 hrs. What can I check before I change out bulb. Happened once yesterday and once today.

------------------
Jan Hackett
Theater Operations Manager
Extreme Screen Dynatheater
NM Museum of Natural History Foundation

Posted by Pat Moore (Member # 380) on 05-18-2002, 11:45 AM:

Jan -- Need a little more info. An "intermittent" anything is harder to find than anything else, simply because of its disappearing nature.

Did the line contactor actually open and then close again? The system's down only five seconds? How far into the show is this occurring? High Reactance or Switcher?

If the contactor is opening then the problem is likely interlocks, door or air. I'd suspect air interlocks first, especially the exhaust. That bracket is designed to be bent up into the stack at about a 30-degree angle, to be sure it's in the air flow of the exhaust pipe. Has it been really windy? I've had situations where outside wind created so much back pressure it would close down airflow intermittently. Other than that, be sure the intake air flow switch is clean and fully pulled in by a clean impeller on that top fan of the console.

Door interlocks are a possibility. If equipped with the magnetic interlocks, be sure the actuators are positioned correctly and the doors are fully closed. If it's an older console with the pushbutton switch, bend the bracket slightly to be sure the door engages the switch fully.

After that, it's wiring in the rest of the interlock circuit going back to the contactor in the power supply. It's not thermal because five seconds is too short a time too cool down anything enough to close a thermal switch again.

If the contactor's not dropping out, the lamp is the first suspect. Try and watch the arc, it would normally waver like hell before it extinguishes. Problem is that you'd be really lucky to actually see that, given it's still a rare occurence. You should see quite a bit of waver when it's running, if it's getting that bad. It could be a loose DC connection so check your DC cable connections, but I'd bet against that. It would heat up to the point where resistence is too high and you'd lose current flow, but that prioblem would occur at a rapidly increasing rate and not just once a day or so.

Pat

Posted by Gordon McLeod (Member # 33) on 05-18-2002, 04:36 PM:

I have had problems with the UV eating that thin shield cable in some highlights giveing grief on the interlocks
Also the molex connectors on that circuit board with the switchs and meter can get bad contacts

Posted by Pat Moore (Member # 380) on 05-21-2002, 09:08 AM:

Jan -- anything new on this problem?

Pat

Posted by Paul G. Thompson (Member # 655) on 05-22-2002, 10:33 PM:

More information needed.......

It could be a goofy airflow interlock, maybe a door interlock, etc. If the igniter does not fire almost about one or two seconds after the bulb goes out, I doubt if it is the bulb that is causing the problem. It is probably an interlock problem. Do you have a stack airflow switch in that thing?

Posted by Jan Hackett (Member # 1231) on 05-24-2002, 11:15 AM:

Thanks all.......... Turned out to be bad belt on exhaust on roof that vents lamphouse. Was causing air interlock to engage.. Thanks for the help.........

------------------
Jan Hackett
Theater Operations Manager
Extreme Screen Dynatheater
NM Museum of Natural History Foundation