Film-Tech Forum ARCHIVE: Xenex auto igniter failure

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Posted by Giorgio Volpi (Member # 1182) on 04-14-2012, 03:48 PM:

Hi to all,
I have three xenex lamphouses with no auto igniter.
I bought three new auto igniter boards, but two lamps don't start.
I tried all boards in different lamphouses and they work only in one of them. I'm using the same lamp type (2KW Philips) and rectifier (Kneisley).
I didn't measured no load voltage, but if this is the problem, how can I adjust it with Kni-Tron rectifier?
Thanks in advance for your help.
Giorgio.

Posted by Monte L Fullmer (Member # 2797) on 04-14-2012, 04:07 PM:

If two won't start, I'd point it to the source, like an open circuit within the lamphouse prior to the autostrike assembly..like a safety switch for starters.

On top of the rectifier, is a door. Under the door you will see a bar that is tied across three taps (which represent each trans former's secondary windings).

You move the tap to the right to increase output current.

I always maintain never use the last two taps on the rectifer to the right, for Kneisley's are not too good in being tolerant and will blow a transformer open quite easily if over driven..and you got a 'boat anchor' afterwards.

A 2k bulb's DC operating voltage should be between 22 and 28 VDC. No-load should be close to 100V.

Posted by Giorgio Volpi (Member # 1182) on 04-14-2012, 04:25 PM:

Thanks Monte.
Lamphouses had no circuit cables, for auto igniter board. I put them in with same scheme. I tested them and are Ok. No switch is present.
The board works in parallel with manual button, and that works fine.
I checked DC current with external tester and it's fine.
I will check no-load voltage on Tuesday and will inform about.

Posted by Monte L Fullmer (Member # 2797) on 04-14-2012, 04:36 PM:

Almost sounds like the break relay on the autostrike board isn't making the connection..even though they be new.

EDIT: Please forgive me, just trying to help here..but do remember an igniter issue in one plex I worked at moons ago that had XENEX units (we had manual ignitions-just flip up the power switch and push the ignition button-, no autostrike boards..) where one did fail to ignite and it was pointed to the ingiter. Something underneath the igniter had broken causing the igniter to not strike the bulb.

Wonder if this would be your issue on ignition failure.

thx-Monte

Posted by Barry Floyd (Member # 385) on 04-14-2012, 05:52 PM:

Words to the wise.. If you end up moving the tap bar on the Kniesley rectifier, make sure you get both the top and bottom bolts tightened securely. Mine worked loose last year and literally arced enough to weld the bolts to the tap bar and burnt a hole in the tap board. Couldn't figure out the smokey fire smell until I noticed the screen had gone dim. Opened the door and could see a hole all the way to the bottom of the rectifier.

Posted by Giorgio Volpi (Member # 1182) on 04-15-2012, 06:57 AM:

I'm sorry, but I was not clear with my explanation.
As I wrote previously, the lamp turns on with manual button, but not with auto ignition board.
The auto ignition board that doesn't work in theese two lamphouses works fine in a third one. So, the board has no problem, like lamp and rectifier.
Surely the problem is about DC voltage at 68V Zener diode terminals. Do you know what is the correct voltage the board needs to strike? If the voltage is insufficient, how can I increase it?

Posted by Monte L Fullmer (Member # 2797) on 04-15-2012, 03:01 PM:

Have you tried to swap around igniters - another area to condemn out of the equation since we got autostrike units and rectifier are working fine.

This is all from one rectifier, correct? If one lamp can strike on 68VDC no load, then we can leave the rectifier alone.

Yet, wonder if the diode bank in the rectifier could use new diodes, since they can get tired.

Posted by Timothy Eiler (Member # 383) on 04-18-2012, 07:08 AM:

Might want to look at the Capacitor on the dc output of the rectifier as it has a dual purpose of aiding ignition and reducing ripple voltage