Film-Tech Forum ARCHIVE: Help with an ORC M1000

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Posted by Sean Weitzel (Member # 244) on 06-20-2004, 04:09 AM:

I have this ORC M1000 unit with 8000 hrs on the clock. The tag attached says that it was tested good in 1994. I have an Osram 1000w bulb installed. Here's what it does:

I plug it into 120VAC and flip the white switch. Both fans spin up and blow lots of air. The 1/2 amp circuit breaker button is out. I push the button and nothing happens. Approx 10 seconds later, the button pops out again. I twist the knob on the back down lower, and higher. Same symptoms. I read the manual and it says that this button is the ignitor circuit breaker. I gather that there is a short somewhere. Anyone familiar with this lamp want to venture a guess as to what might be shorted and where I should begin my troubleshooting? Thanks so much!

Posted by John Anastasio (Member # 607) on 06-20-2004, 06:31 AM:

I think you've diagnosed it properly. The igniter is obviously charging and firing, otherwise it wouldn't be blowing the circuit breaker. Check the lead at the front of the unit where it goes up and over the reflector. Chances are it's arcing to the metal mirror. Thre's a real sharp edge there and that wiring is probably dried out and cracked by now, compounding the problem.

Posted by Mark Gulbrandsen (Member # 72) on 06-20-2004, 09:36 AM:

Typically if the positive bulb lead is shorting out to the front dowser plate you will hear a loud popping sound when the lamp fires, H-V arcing and shorting out. Best thing to do to get some idea of whats up is to measure the no load dc at the lamp but be sure to disconnect the ignitor first by pulling the nylon plug apart under the reflector so you don't take a hit from any H-V. I've seen just about everything possible go wrong with the 1000, but the good thing is that the electronics in them are still totally servicable..... all semiconductors and small parts are readily available. What I normally do is to do a complete rebuild on one. caps, semi's and such. They typically will run for many many years if you do.

Mark

Posted by Paul G. Thompson (Member # 655) on 06-20-2004, 02:17 PM:

Check to make sure the + lead to the bulb is not resting against the mirror. Just for the heck of it, check to make sure the blocking diode is not shorted.

By looking at the schematic, there is a distinct possibility you have a SCR board failure. The open circuit line bridge input, bridge output, SCR input and SCR output are all interlaced with each other in the SCR board.

[ 06-20-2004, 04:32 PM: Message edited by: Paul G. Thompson ]