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Topic: H-10 rectifier noise

Harry Robinson
Expert Film Handler

Posts: 155
From: Franklin Tennessee
Registered: Dec 1999

posted 06-13-2001 10:27 AM

I just installed a new 1K bulb in my old Christie H-10. The increase in brightness was startling. With the old bulb in place the H-10 would occasionally buzz when placed in the high intensity setting, but it was not all that bad.

The new bulb has this thing going into little conniptions. First, there's a "rattley" noise that hangs around quite a bit, then it goes into the "buzz" mode for a while, then it kind of quiets down. Then it might start the whole thing all over again.

I talked to Jim Duncan in Decatur AL, and he said that the problem can be alleviated by tightening the transformer the same way you would tighten down a cylinder head (or in my case, a banjo head). What's the consensus of opinion here? And does anybody have a manual for the H-10 that will guide me to the transformer so I can fix it?

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999

posted 06-13-2001 11:43 AM

A while ago, there was a topic regarding rectifier transformers that vibrate. I never used that paticular rectifier, but others I have used do different things to quiet the laminations. On IREM supplies, there are tensioning brackets and screws that are tightened in a sequence to compress the lamations. On others, (I've read here at FT) the manufacturer gives you plastic wedge blocks that you hammer in between the lamantions (!) I've never seen where the existing bolts on a transformer have loosened up, (the ones holding the steel laminations together) so I don't know if that will work. Maybe the regular mounting bolts are what's loose. If any are loose, try tighting them in different sequences, to different torques.

I would guess that with a smaller transformer (that would power a 1K bulb) there may not be much that can be easily done. The newer bulb probably draws more current than the old, which is why it started buzzing worse. I guess if all else fails, you might mount the transformer on rubber mounts, but that sounds like a lot of work.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 06-13-2001 05:16 PM

The best way to fix it is to pound wood wedges between the transformer frame and the winding. This may involve taking the entire thing apart to be able to do this. Its not all that uncommon. Strond high reactance also will do this. I havce fixed many of these with wedges.....which should be oak to survive being pounded in.
Mark @ GTS

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