Film-Tech Forum ARCHIVE: Westrex 2001 strange shutter ghost problem

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Posted by Matthew Taylor (Member # 2310) on 10-20-2006, 04:44 PM:

I have a friend who runs a small cinema and uses an old Westrex 2001 projector. He is having a problem with some wierd ghosting that cannot be adjust out using the timing knob. It appears at towards the top AND bottom of the screen. The ghosting goes in a downwards direction at the top and upwards at bottom with no apparent ghosting in the middle.I suggested he paint the shutter blade because it was bare metal but this has made no difference.

Any ideas anyone?

Posted by Rick Raskin (Member # 1561) on 10-20-2006, 04:58 PM:

Is the machine a double shutter mechanism? If so then I suspect the shutters need to be re-timed.

Posted by Matthew Taylor (Member # 2310) on 10-20-2006, 05:04 PM:

I am not sure. Is a double shutter usual for these machines?

Posted by Pete Naples (Member # 761) on 10-20-2006, 05:24 PM:

Did someone mention Westrex [Smile]

Double shutter was rare, not unheard of but rare.

Now there are a couple of things that spring to mind.

One, the sliding gear on the vertical shaft, if it's worn on it's keyways, then you get ghosting, similarly if the entire gear train is sloppy you'll get ghosting.

Two, the shutter needs to be sited on the shutter shaft as near to the aperture as possible.

Three, hole in the shutter blade? You'd be amazed at the number I've found with holes burned in them, or with the blades badly warped.

Four, the Westrex blade was very tight, so as to maximise light output. Now with todays efficient lenses and xenon lamps, often we find that we can go to a wider shutter blade. IIRC the standard Westrex blade was 90º, I usually fit a 100º blade on memory, or the adjustable type.

Posted by Richard May (Member # 2627) on 10-20-2006, 06:43 PM:

Like Pete said. Sounds most likely to be the sliding gear on the vertical shaft. Whenever I see ghosting up and down, its usually that gear.

Posted by Sam D. Chavez (Member # 1841) on 10-20-2006, 08:12 PM:

I've seen this when Century's are coupled with fast mirrors of earlier xenon lamps. The cone of light is wider than the projectors were designed to deal with so the light goeas around the edge and end of the blade.

Posted by Ken McFall (Member # 845) on 10-20-2006, 08:43 PM:

Shutter timing would normally result in a ghost at the top OR the bottom not both. So clearly the problem is not simply a timing issue.

You can take everything Pete say's as gosple as he has a lot lot of experience in Westrex projectors. Scotland possibly had, or still has, the most Westrex installs running.

You don't say if this is a new problem, equipment running fine until recently, or a 'new' install that has an unexpected problem.

More information on the type of lamphouse and if it's a single or double shutter mech would help.

Posted by Demetris Thoupis (Member # 833) on 10-21-2006, 01:40 AM:

Something silly. Is is possible that he has a cracked lens!?
D

Posted by Pete Naples (Member # 761) on 10-21-2006, 04:50 AM:

Sam, that's exactly why I fit the wider shutter blade on them. It's usually older machines that suffer from this. Some of the late ones from the dawn of xenon came from the factory with a wider blade.

Posted by Matthew Taylor (Member # 2310) on 10-21-2006, 05:31 AM:

Thanks for all your input on this. I will hopefully get a chance to see exactly what gear he is using and give some more detailed info this weekend. You've certainly given us a few things to go on.

Posted by Louis Bornwasser (Member # 3063) on 10-21-2006, 08:15 AM:

FYI: Westrex 2001 and Century "C" are virtually the same machine. In fact I routinely use old Westrex intermittents in C overhauls.

This is the classic case of "shutter oscillation." Follow all instructions above. If not yet successful, change the shutter bearings and, in the case of Westrex, assure that final alignment includes assuring that the bearings are "in line," Only on westrex there is an eccntric adjustment in the forward shutter bearing assembly.

I make a new style shutter assembly which guarantees precise alignment of the bearings for old Centurys and I could check a westrex casting I have for you, BUT check everything else above first.

BTW: it is not necessary to go over 90 degrees on the blade. In fact, it may be possible to go back to the 83 degree blade. Louis

Posted by Matthew Taylor (Member # 2310) on 10-22-2006, 11:24 AM:

Just an update on this - I conveyed the information to my friend and he adjusted the shutter to sit closer to the aperture and this has made the ghosting almost negligable now. I recommended that he also paint the inside of the shutter housing and the blade matt black to reduce this even further. There still may be some slack on the gearing as well, he hasn't checked this yet.

Many thanks for your good advice [thumbsup]

Posted by Pete Naples (Member # 761) on 10-25-2006, 08:30 AM:

Glad to be of service.

BTW painting the shutter and it's housing black, in my experience won't make any noticeable difference, it's transmitted, not reflected light that's causing the ghosting.

How did your friend get on with gear train/keyway wear? ideally there shold be no rotational play in the sliding gear keyway, any more than half a pubic hair spells trouble. The correct settings for the backlash in the rest of the gear train can be found in the manual, which I think is in the downloads section of this site. If it's not pm me and I'll email you it.

Posted by Matthew Taylor (Member # 2310) on 10-25-2006, 03:40 PM:

Hi Peter,

He isn't really very technical and although I explained how to check the play in the gear train and vertical shaft he said he wanted me to come over and do it - so far, I've not had time. I will however go there with my ISO-certified pubic hair measure and check [Big Grin]