Film-Tech Forum ARCHIVE: Christie CH 10 DC switch, NEED HELP

This is topic Christie CH 10 DC switch, NEED HELP in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ben Mozer (Member # 3401) on 10-27-2010, 02:33 PM:

I had the DC connector in the rectifier short out last night. The AC wire seemed to have come into contact with one of the heat sinks, which caused the short, so the connector makes a loud buzzing sound when the manual DC switch is thrown. I replaced the connector in the rectifier, but it still doesn't work and still makes the loud buzzing sound. I am, admittedly, an amateur at this, so I don't know what to look for next and my repair man can't get here for a couple days.

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 04:31 PM:

Seriously though, I really really need some help. If I'm asking in the wrong way or not giving enough info, let me know and I will correct it.

Posted by Richard May (Member # 2627) on 10-27-2010, 05:05 PM:

I think it's just confusing that the connector is making noise. Could the noise just be coming from somewhere in the rectifier that you can't pinpoint? Sounds like it may be a shorted diode.

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 05:09 PM:

It may be from something else, but it sure seems like it's coming from the DC connector. When I flip the manual switch to strike the lamp, that's when it starts buzzing. When I take the panels off the listen for the noise, it sounds like it's coming straight from that connector. Also, it may be a diode because the insulation on the AC wire was burn through and actually making contact with the heat sink. But, if it's a diode, why does it sound like the connector is buzzing? Do I need to replace the diodes or the entire heat sink? Could there be more shorted out than just that?
L
ike I say, I'm no expert on this by any stretch of the imagination.

Posted by Richard May (Member # 2627) on 10-27-2010, 05:17 PM:

Did it happen in the middle of the show or at start up? Exactly what happened?

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 05:19 PM:

It happened last night when I wasn't here. But, from what I can tell, it happened right at the start of a show. I'm guessing that the wire was laying on the heat sink for a while and the insulation finally melted through at the beginning of that show.

I think I'm mostly afraid that I have to replace the entire rectifier now....that would be pretty pricey.

Posted by Richard May (Member # 2627) on 10-27-2010, 05:22 PM:

Usually when a diode shorts, it trips the breaker. Sometimes, especially with Christie rectifiers, it doesn't trip the breaker and makes this low pitched LOUD hum or buzz. It could be a shorted diode that didn't trip the breaker and overheated the AC wire.

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 05:25 PM:

I've had to replace diodes before, and this didn't seem like a diode problem to me. But I might replace those for good measure (hopefully I have a positive AND negative) and replace that wire as well.

Posted by Richard May (Member # 2627) on 10-27-2010, 05:27 PM:

Test them all first to see. From what you're telling me, it sounds like it.

Posted by Jeremy Weigel (Member # 4208) on 10-27-2010, 05:33 PM:

Just to be certain, you're not talking about a contact relay that's making a buzzing sound?

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 05:38 PM:

Yeah, I think that's what it is (I don't know all the jargon yet). It's the mechanism that flips in the rectifier when you turn the Manual DC on.

And what, exactly, do I touch with the voltmeter to test each diode?

Posted by Richard May (Member # 2627) on 10-27-2010, 05:46 PM:

Even so, I still think it may be a diode. I don't know what would buzz on the contactor. With an ohm meter you check each diode one by one. Take it off the heat sink. Put one lead on the threads and the other lead on the stem. Then switch leads. If it's "closed" in both directions, it's shorted.

Posted by Jeremy Weigel (Member # 4208) on 10-27-2010, 05:53 PM:

I've had contactors that have gotten weak and will buzz. Usually you can lightly tap on the top of it and it will finish pulling down the contacts or on some you can actually push the contact bar down.

Posted by Richard May (Member # 2627) on 10-27-2010, 05:58 PM:

He said he replaced it with another one though.

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 06:00 PM:

Yeah, I replaced the contactor. The old one was OBVIOUSLY burnt out. But the same problem persists and the lamp won't ignite.

Posted by Richard May (Member # 2627) on 10-27-2010, 06:04 PM:

I'm sticking with a diode. [Smile]

Posted by Ben Mozer (Member # 3401) on 10-27-2010, 06:54 PM:

Ok, I replaced the diodes in the heat sink that caused the shortage and the AC wire that was over heated and the noise is definitely coming from the Connector. The problem persists.

Posted by Richard May (Member # 2627) on 10-27-2010, 06:57 PM:

You checked ALL the diodes?

Posted by Louis Bornwasser (Member # 3063) on 10-27-2010, 09:45 PM:

I'm afraid this is pointless. Louis

Posted by Sean McKinnon (Member # 612) on 10-29-2010, 10:27 PM:

Did you replace all of the diodes? Usually a direct short will damage the diodes and could be causing your symptoms.

Posted by Manny Knowles (Member # 1171) on 10-29-2010, 11:31 PM:

Oh my.

Posted by Richard May (Member # 2627) on 11-02-2010, 02:05 PM:

[eyes]

Posted by Richard May (Member # 2627) on 11-03-2010, 02:14 PM:

Maybe it blew up [Eek!]

Posted by James Westbrook (Member # 3690) on 11-03-2010, 04:03 PM:

Could be worse. He could have had a Rentec.

Posted by Tony Bandiera Jr (Member # 2365) on 11-10-2010, 03:28 PM:

I guess Ben either DID get blown up or he gave up on it. [Roll Eyes]