Sunday, March 7, 2021

 

FILM LOADING PROBLEMS

INTRODUCTION

The film’s feed reel sits on the post at the top of the camera and allows the film to be pulled through the gate. The claw, using a combination of pressure plate tension, the pulling action of the take-up reel, and the film drag roller (located at the bottom of gate area) all combine forces to pull the film intermittently through the gate. 

When the claw is not actively pulling film with the motor running, the film is held in place and does not wind onto the take-up reel. An overrunning clutch on the take-up reel keeps tension on the take-up reel at all times the motor is running. If the film slips out of synchronization, the camera will stop and/or not start. This usually means one or more of the following has occurred:

   11)   The film has slipped out of the center slot of the take-up reel and is not being pulled through the gate and wound onto the take-up reel. The camera’s claw will misregister and stop.  This is the most common cause of film stoppage.

You cannot directly see if the film has slipped out of the take-up reels’ slot. It is typically held in place with 2 or 3 turns of film stock. If the end of the take-up reels film falls out of the reel’s slot, the reel will then not be able to pull film thru the gate properly and this will cause a mis-registration and the camera will stop.

Any time the claw is out-of-sync with the  film’s registration sprocket holes, the claw will mis-misregister and the camera will stop. Usually, pulling out and then pushing the  pressure pad or claw lever, will correct any registration problems. This will not fix a film leader that has slipped out of the take-up reel’s slot.

 2  2)   The film slack tensioner is located at the top of the gate area and pivots at the tip of the claw cover. Its purpose is to take up the slack and smooth out the “tugs” that the claw imposes on the film stock. Sometimes the tensioner's small coil spring breaks or  the spring’s tip can “pop under” it’s retainer bar and the spring then becomes ineffective.

When the film is then pulled through the gate by the take-up reel, the tensioner, if not properly doing its job, may cause the film’s drag to exceed the maximum allowable and the film may become misregistered resulting in the camera stopping. This can be an intermittent or continuous problem.

3)  3) Another problem is the pressure plate backing spring can become weak over time, thus allowing the film to be pulled through faster and cause misregistration.

4)   The previous owner of the camera may have added and short length of electricians tape to the front of the pressure plate to add additional “drag” between the film and the tensioner.  The tape may be the cause of the problem. 

5) The gate area can be dirty and cause excessive drag.

6) A worn or damaged lower drag roller and the bottom of the claw cover can     allow the film to intermittently move out of registration and the camera will stop.

7) The tip of P1-2-3 reflex camera’s lower drag roller’s backwind pawl spring, located at the lower section of the claw cover, can break. Tip breakage or slippage can allow the take-up reel to move the film faster than normal and cause the camera to misregister.

8) The take-up reel clutch can partially or intermittently seize which can cause the camera to misregister.

If these common problems aren’t the cause, it may because one or more of them are intermittent and interacting with each other. If inspection showed no obvious problem(s), I recommend running a test roll (old or used film stock) through to find and fix or eliminate the problem.

GATE REEL SLIPPAGE TEST

Using the ½ roll of film and with the door open, thread the ½ roll of film onto the take-up reel and run about 10 seconds of film and then, with your finger tip and the camera still running, press down on the bottom part of the take-up reel, slightly, to stop it from turning. With the reel stopped, let the camera run for another 5 seconds or so. Then take your finger off the take-up reel and watch the take-up reel “pick up” the slack. You can see the loose film wind itself around the take-up spool taking up the excess slack.

After 5 more seconds of the film being rewound onto the take-up reel. Stop the motor and try turning the take-up reel clockwise with your finger. It should stop within one turn. If it continues to turn indefinitely, the film’s leader has slipped out of the reel slot.

 

 

 

FILM  LOADING  PROBLEMS 3-3-2019