Film-Tech Forum ARCHIVE: (Christie) SLC 45/70-342

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Posted by Peter John Anthony. C (Member # 2500) on 08-27-2005, 03:48 PM:

Can any one help me out with the above model lamp house.

The problem is when i turn on the Console thje circuit breaker just trips down.

Request to guid me with necessary check list.

Thanks
Peter

Posted by Bevan Wright (Member # 1884) on 08-27-2005, 04:41 PM:

1. Shorted diode
2. Short in transformer

Posted by Steve Guttag (Member # 268) on 08-27-2005, 06:01 PM:

I would go with the shorted diode. Particularly if there is a delay on when you turn the lamp on, hear the contactor "clunk" and then the breaker seems to lazily turn itself off.

But in any event...start with the diode, it is much more common than the transformer.

Posted by Darryl Spicer (Member # 711) on 08-28-2005, 12:02 AM:

little clarification please. When you say you are turning on the console do you mean you are turning the console on or you are striking the lamp. The circuit breaker that is tripping is it on the console or in the wall panel breaker box?

Posted by Fabrice Dubourg (Member # 1635) on 08-28-2005, 05:36 AM:

just start with the diode, common problem...

Posted by Mark Gulbrandsen (Member # 72) on 08-28-2005, 03:35 PM:

Its also possible that the breaker has mechanically failed and just will not hold at the operating current. I've seen this quite a number of times. This is more common where the breaker is also used as a switch. This is a bad thing to do as a breaker is rarely designed to be used as such.

If you do find that its a bad diode then it is best to change ALL of them in any given rectifier. They are all the same age and have been through the same number of thermal cycles et all. You may be just chasing your tail and find that you have a regular rash of diode failures in the same unit unless all are replaced at once. Also look for a mechanically loose stem... this is very common on those cheapo epoxy passivated International Rectifiers diodes that Christie uses. If possible try to find some glass passivated diodes to replace the IR's. The glass passivated units don't suffer the same type of thermal failures that epoxy passivated diodes do.

Mark

Posted by Peter John Anthony. C (Member # 2500) on 08-30-2005, 09:38 PM:

Darryl Spicer the circuit breaker that was tripping was on the console.

Thanks for all your support, the problem was due to short transformer that step down voltage & gives supply to the zipper.

Thanks once again.