This is topic xenex pup lamp focusing in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Dave Ganoe (Member # 53) on 05-02-2001, 02:27 PM:
I got a xenex pup and when putting in a new bulb I cannot get even screen illumination. The corners are kinda dim. This is no matter what position the lamp is in, the reflector, or the lamphouse itself in relation to the projector. Seems almost as if there is not enough adjustment in the focus travel of the bulb itself. Any clues or advice. Thanks.
Posted by Gordon McLeod (Member # 33) on 05-02-2001, 02:45 PM:
THe pup is a pig to line up. Is it at the correct working distance? I believe it should be 28" from the vortex of the mirror to the apperture (will have to check as I can't remember if it was 32" for that model but 28" is dticking in my mind)
Is it is a perfectly straight line to the lens?
Is the correct lamp installed. Some lamps require the 2 side pins to be removed to work in the pup
Posted by Dave Ganoe (Member # 53) on 05-02-2001, 02:48 PM:
Gordon,
THe bulb has the pins in it. The xenex calls for a 1000 or 1600 watt but I found that a 750 has the same dimensions as the 1000 and 1600 so I chose to go with the smaller wattage lamp. If the pins should be out are they easy to remove from the bulb without damaging the bulb or having it blow?dave
Posted by Gordon McLeod (Member # 33) on 05-02-2001, 02:51 PM:
I used to use a dremel tool with a cutoff blade in it to cut off the pins on the toshiba lamps we used to use in the pups years ago
Check and see if the are touching the mirror bushing if not then that isn't the problem
Posted by Gordon McLeod (Member # 33) on 05-02-2001, 03:17 PM:
I just checked with the manual and it is 28".
Also if it is an OSRAM or ORC lamp it should niot be necassary to remove the two pins. In fact the drawing shows the adapter sitting in the bushing in the manual. It is on line.
I do remember that with the toshiba lamps they were a pain
Posted by Greg Pauley (Member # 503) on 05-04-2001, 02:59 PM:
Dave,If all of the above doesn't work, you might have the bulb out of position in relationship with the reflector. Just had this problem this week after someone changed the bulb in a pup and couldn't dial in the focus. The bulb was pushed back to far in the holder making it impossible to focus. The pup is a budlight lamphouse, everytime you change a bulb, you require a bud!