Film-Tech Forum ARCHIVE: 16mm Xenon Rectifier Question / Problem

This is topic 16mm Xenon Rectifier Question / Problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mike Blasko (Member # 3968) on 08-23-2009, 10:39 PM:

Hello -

I have a question for anyone who remembers the wave of Atlantic Audio Visual Xenon conversions from about 20-30 years ago. I have a Singer Instaload 16 version of this conversion that I am interested in keeping running for the simple reason that it uses Bell and Howell lenses and an XBO 450 W/2 lamp, which can be had easier and cheaper than other versions of the like.

The lamp went out with the meter showing about 800 hours (who knows if this is the original power supply or not) and a mostly darkened envelope. I assumed naturally that a new lamp was all that was needed. Several times before the lamp failed, there were multiple strikes needed to hold the arc etc.

With a new lamp in hand, it will not strike.

Here are a few things I've noted:

1). Output from the terminals is about 100VDC.
2). I've yet to hear the two relays click, nor are they seeming to receive the 24vdc to close the coil.
3). The cathode on this lamp is longer and is thus touching itself inside the lamphouse connection point (but nothing else).
4). Power supply does turn on and looks good at a basic level.
5). There was some question on how the terminals connected, but it appears that is resolved.

I'd like to fix this if it's easy, but i'm not sure where to go next. I'm replacing the two relays as that's easy.

I have some old ORC Xenon slide projector rectifiers that are around the same wattage / voltage. Is there any thing special about this Atlantic rectifier, or can I move on to something different ?

Literally, there are two wires coming off the lamphouse into a 20amp stage pin connection.

I've uploaded a few images, if anyone has any ideas, parts or thoughts, please let me know.

Thanks very much for anything you might be able to contribute.

Regards,

Mike

Posted by Monte L Fullmer (Member # 2797) on 08-23-2009, 11:55 PM:

There could be an autostrike unit in there that has failed - why you don't hear the relays clicking..

Posted by Gordon McLeod (Member # 33) on 08-24-2009, 12:43 AM:

they were very common often on Bell and Howels, and Kodaks
check the zenier on the autostrike

Posted by Mike Blasko (Member # 3968) on 08-24-2009, 12:54 PM:

Thanks for the help guys. I'm going to replace the relays and the Zener diodes. There are three on the board, do I need to replace all three, or just one ?

The part number matched up with a 10W, 20v forward D04 (screw mount like mine) diode, so I think that makes sense, alas the coil on the relay is 24 ?

That's what was in there before it went out (worked for at least 800 hours).

Is this the most common issue with these things ?

If this doesn't work can I use any rectifier with like voltage / amperage or are there tricks to this ?

Anyone got a schematic or extra supply ?

Posted by Gordon McLeod (Member # 33) on 08-24-2009, 03:31 PM:

Most common failure was the high voltage grounding out on the run up to the lamphouse

Posted by Mike Blasko (Member # 3968) on 08-24-2009, 04:35 PM:

Thanks Gordon -

Yeah, I could see that happening, it's tight quarters up there and only a piece of wood holding it all together !

I like the design though and I like XBO 450 lamps. Kudos to them for using an easy and smart lamp. Anyway to test for the ground out ?

Anyone have a schematic ? Spare ?

Thanks again !

Mike

Posted by Gordon McLeod (Member # 33) on 08-24-2009, 05:15 PM:

Years ago I used to have those drawings but several shop floods later I don't
THe manufacturer of the powersupply was
http://allanson.com/en/home.html
you may find they still have drawings for
it

Posted by Mike Croaro (Member # 3123) on 08-24-2009, 10:46 PM:

Hi Mike:

Good luck getting your unit running again. Don't forget to check over at www.16mmfilmtalk.com. There are a few goys over there who really know their stuff about the 16mm xenons.

Mike