Film-Tech Forum ARCHIVE: Simplex 35 Focus Problem

This is topic Simplex 35 Focus Problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=002350

Posted by Marc Jones (Member # 29) on 06-03-2001, 09:33 PM:

Problem: I can focus the image to where the center of the film is in but the right side is out of focus. The projecter has a curved gate. I replaced the bands, I replaced the curve piece on the front of the gate and still no difference. I tried moving the top mounting point of the bands thinking maybe this might be my mis alignment. The only thing that I have found to effect the focus is after the projecter is load to push on the handle to reduce the tension on the gate.
Any Idea I 'm out.

Posted by John Walsh (Member # 168) on 06-03-2001, 10:18 PM:

What type of Simplex.. Does it have the turret or single lens holder? If so, does it have the optical/mag centering option?

Has it always been like this, or happened recently? If you borrow a lens from another projector and put it in, is the focus still uneven?

If the gate and trap look undamaged, I'd look at the optical alignment.

On turret models, I had a problem where the set screw that positions the turret (when closed) was loose and unscrewed a bit. An operator unthinkingly tightened it, then kicked the projector over to recenter the image without telling anyone. It took a while for me to realise what was wrong.

Posted by Randy Stankey (Member # 64) on 06-03-2001, 10:38 PM:

The specific model of projector would help but I'm going to make a guess that you have a PR-1050, or thereabouts. Is there a turret on this baby? If so, which flavor? Again, I'm guessing that it's one of those horrible TU-2000 clunkers. (The one where the turret opens and closes when the lenses rotate.)

If the right side is out of focus (with above assumptions) one common cause of this is the turret not being perfectly parallel with the film plane. Usually it's not closing far enough because some junk is lodged in between the turret frame and the stop screw. A good way to tell this is to flip the turret switch on the front of the machine to the "thread" position and hold the turret shut with one hand. Then carefully move the turret open and shut. It'll probably only be off by a millimeter or two so be really accurate about it. If you can find a place where the picture is in focus then take a look for crud built up somewhere. Otherwise you can adjust that stop screw.

If that doesn't work there's another place you can look. There are three allen screws around the perimeter of the turret that hold the round "lens board" into the turret frame. Press on the lens board in a few places and see if that helps. A sure sign of a problem here would be a shaky picture as well as a focus problem. Pressing on the lens board will also stop the shaking.

Another piece of information would be whether this problem happens only with one lens. (Flat or scope.) If this is the case then check the tightness (and paralell-ness) of the lens and the mounting collar for that particular lens.
One more place to look if you have exhausted all other possibilities is one of the lenses themselves. If one of them has been dropped... or if somebody tried to spin the turret when it wouldn't open, the elements could be knocked out of whack. The test for this is to swap lenses with another projector and see if the problem moves with the suspect lens. (Just don't mix the lenses up, dammitt! )

If all this doesn't work, then I'd go looking at the trap/gate area and see if all the guides are running free and set properly, etc. I'd rule out the turret and lenses first because this is a lot easier to do.

Eliminate the easy things first, I always say!

Posted by Paul G. Thompson (Member # 655) on 06-03-2001, 11:41 PM:

Make sure the film trap is seating properly. Sometimes when they are removed for cleaning, they can cock a little if care is not taken to insure proper alignment.

I had a problem identical to yours. The problem was one of the the P-1633 support studs was bent. I was able to straighten mine out with a nut driver handle.

Posted by Marc Jones (Member # 29) on 06-04-2001, 11:17 AM:

The model is PR -1014
I move the problem from one screen to another by moving the gate assembly, front and back part to another auditorium. So I think I have the problem to the gate parts.
Thanks Again

Posted by Randy Bowden (Member # 587) on 06-06-2001, 01:00 PM:

Check the Lateral guides on the trap. The inboard portion of the lateral guide should move move if you push on it and spring back if you let go. I have seen these things get stuck shut and have the exact problem you just described.

Posted by John Pytlak (Member # 331) on 06-06-2001, 01:10 PM:

Randy Bowden --- good suggestion about checking the lateral guides. "Pinching" the film as it enters the gate would cause a focus issue.

BTW, several SMPTE standards specify that the "REFERENCE EDGE" of a 35mm print is the analog soundtrack side. This is the side of the print that is pressed against a "fixed guide" in the printer and projector to maintain optimum horizontal steadiness. The other edge of the print is the one that normally goes against a spring-loaded guide or roller.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Matthew Bailey (Member # 601) on 06-06-2001, 10:26 PM:

I too have a Simplex PR-1014 about over 20
years old. However mine has a model 1000
turret with a straight trap & gate.

Posted by Gordon McLeod (Member # 33) on 06-07-2001, 10:38 AM:

Since reduceing gate tension helps it is possible that there is more tension be placed on one side than the other.
It is possible that the bands are not set properly and are angling inward slightly.
Also the trap may have been dropped at some point bending it slightly so one side is skewed