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Author Topic: I am a novice looking for advice on a problem print and or projector John Davey Film Handler Posts: 16 From: Chesterton, Indiana, USA Registered: Jun 2008 posted 06-21-2010 03:14 AM                     Ian, Yes, the machine runs poly without any "dramas". I will definetely look into this. This seems like a very plausable explanation.. I know the intermittent sprocket on this particular machine feels different than the intermittent sprocket on the other machine in our booth. The "teeth" seem more recessed. Where on the ohter machine, when threading you can definetely feel the teeth portruding through the sprocket holes, on this machine, the teeth seem shorter and don't stick out as much through the sprocket holes.  |  IP: Logged James Westbrook Phenomenal Film Handler Posts: 1133 From: Lubbock, Texas, Usa Registered: Mar 2006 posted 06-21-2010 03:28 AM                     I sympathize with you, John. We are in the same boat in that we have to make do with the projection equipment we have, even if it's less than stellar. The intermittent sprocket sounds like it needs to be replaced by your description of the teeth being shorter. I would replace the pad shoes on that film trap, too. These hold the film against the intermittent sprocket when the trap is closed. Sprockets and pad shoes should be available via Strong or your projection parts dealer.  |  IP: Logged John Davey Film Handler Posts: 16 From: Chesterton, Indiana, USA Registered: Jun 2008 posted 06-21-2010 03:29 AM                     Just to be sure I know what I am talking about, the intermittent sprocket is the on located directly below the gate, correct?  |  IP: Logged James Westbrook Phenomenal Film Handler Posts: 1133 From: Lubbock, Texas, Usa Registered: Mar 2006 posted 06-21-2010 03:31 AM                     That is correct.  |  IP: Logged John Davey Film Handler Posts: 16 From: Chesterton, Indiana, USA Registered: Jun 2008 posted 06-21-2010 03:33 AM                     tring not to get off topic, but, I have read/benn told before that the intermittent on this head is problematic. James, can you eplxain, in laymans terms, why this is? Also, while on this topic, I want to see if I have a basic understanding of what exactly the intermittent does. While the top sprocket merely moves the film down to the gate, the intremitent is the one responsible for advancing the film at 24fps and keeping in time wiht the shutter to produce a steady image on screen. Am I in the ballpark at least with this understanding?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-21-2010 04:42 AM                     PRO35's are really a decent machine if ran and threaded correctly with correct loop sizes-not too big or small .. and threaded in frame at all times. I ran PRO's with Christie AW2's in a twin with no problems, but they definitely needed constant attention for normal operation. But, they use a flat trap and gate assembly-similar to the Super/E7 of the Simplex. The gate rails are controlled by them little circular springs that are adjusted individually in the gate...and they probably needed to be backed off considerably if this print damage is occuring. You back it off until the picture on the screen begins to show vertical jump, then start to snug down the springs until the jump quits and that is where you want to stop. The upper and lower sprocket are called 'constant speed' sprockets since they rotate at a constant speed. The Intermittent Sprocket is just that - it rotates intermittently - a quarter turn per complete rotation to stop the film in the trap for a split second so the shutter can cut off the light though the film twice before the next frame pulldown, thus giving you the illusion of motion when viewing the images on the screen Why the shutter needs to cut the light off twice so you won't see 24 pulses of light per second on the screen, but 48 pulses of light per second which makes this unnoticable to the normal eye. WARNING! Don't go crazy with that framing lever since that's the major problem with that machine: for behind that lever is a coupler that couples the intermittent sprocket shaft to the starwheel shaft since the shutter doesn't compensate when needing to frame - just the sprocket compensates via that danged coupler. And that coupler, made of nylon, loves to wear out and it's a pain to replace. Wonder if that danged intermittent sprocket coupler is worn .. -Monte  |  IP: Logged James Westbrook Phenomenal Film Handler Posts: 1133 From: Lubbock, Texas, Usa Registered: Mar 2006 posted 06-21-2010 05:05 AM                     What Monte just said. The framing assembly and the coupler is the weakness on that intermittent. Instead of one long sprocket shaft, we have 3 pieces connected together. More complexity brings more problems.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 06-21-2010 06:20 AM                        You say that the film snaps at the soundhead. Are you using floating-hub reels for takeup, and is your takeup tension adjusted properly? Is it possible that the film is jumping a sprocket or two across the holdback sprocket at the start of the reel, causing too much tension in the soundhead? This would not explain out-of-frame starts, however.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 06-21-2010 06:45 AM                     Down load the manual and there is a section on gate tension  |  IP: Logged Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 06-21-2010 06:57 AM                     Operator caused "out of frame starts" are the result of improper threading of the projector. The intermittent sprocket must be locked in the position for the shutter to open and image to be projected. Simply placing a finger on the intermittent and turning the inching knob or motor shaft to feel when the rotation stops is recommended. At this point the leader is threaded in frame in the viewing port. Advancing the film a few frames by hand will confirm framing after the entire machine is threaded. If there are splices in the leader between the threading point and the picture, they must be confirmed to be in frame or the leader can cause the projected image to be out of frame. This can be caused by out of frame repaired breaks during the "motoring down" prior to starting the projector. KEN  |  IP: Logged Richard P. May Expert Film Handler Posts: 243 From: Los Angeles, CA Registered: Jan 2006 posted 06-21-2010 09:47 AM                     When threading the projector, are you checking to be sure the intermittent sprocket is in its "rest" position? If it is in the "pulldown" position, you will almost always end up with the picture being out of frame when the intermittent is at rest. I have always made it a habit to put my finger on the sprocket (motor off, of course), and turn the motor over by hand until the sprocket moves, then comes to rest. DM  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-21-2010 12:49 PM                     I do the same: rest my finger on the sprocket while I turn whatever device (inch knob, motor flywheel, et.al.) by hand to feel the sprocket come to rest before threading so I'm always in frame on a start. And, it's amazing how the majority of booth personnel don't know this procedure, or they simply don't care to know if shown this procedure. True though, is slip reels used for takeup, or solid reels if using 6k reels ... -Monte  |  IP: Logged Joe Elliott Master Film Handler Posts: 497 From: Port Orange, Fl USA Registered: Oct 2006 posted 06-21-2010 03:09 PM                     I have my guys not only making sure the intermittent is locked, but I drum into them to check the framing 3 times. Advance it by hand while threading, check it again when motoring up (we use a Mylar leader before the regular leader, and they are to thread on the Mylar, and motor up to the regular. That catches potential problems BEFORE start.) At start time they are to strike the lamp and advance by hand a few frames, again checking framing. Then they start it. That way there is no excuse to start out of frame.  |  IP: Logged John Davey Film Handler Posts: 16 From: Chesterton, Indiana, USA Registered: Jun 2008 posted 06-21-2010 05:30 PM                     Monte and James, Thank you for the explanation. That's how I thought it worked but wanted to be sure. My question is: if I adjust the film gate tension for an acetate print, is it going to affect the way the machine handles ploy prints? Ohter than this one show a wekk, all of the film this theatre runs is poly. Scott and Monte- We use both types of reels in the booth. Floating hub and stationary hub. After all of the info I've gotten out of this thread, I think we are running too much torque on the take up and is the reason it has snapped at the sound head. However, the sound head is not the only place it has snapped, so that's not my only problem. Monte, Richard and Joe, I had no idea about the intermittent having to be in a certain position. It makes complete sense now that it has been brought to my attention. I will be implimenting the technique you guys have suggested and will implore the other manager/projectionists to do so as well. Monte, when you say "inch knob" are you referring the the framing knob? if not, where is this "inch knob" Guys, once again, you have given me a world of help. Thanks so much  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 06-21-2010 05:37 PM                     John, Here is some of the best advice you will ever get...find someone who actually knows what he/she is doing to show you how to operate that booth, then get everyone trained. Not trying to be rude, but the questions you are asking are so simple they are "first day of training" issues. The fact you are running one-of-a-kind/last existing prints is downright frightening. The "threading 101" document in the tips section here is on different equipment than you have, but would at least give you an idea of what these guys are trying to explain to you. Is there anyone on here within a reasonable driving distance from John that might be willing to let him come see their booth and watch for a day or two? (Ideally someone who has been doing this long enough to have handled acetate prints back in the early 90s or before.)  |  IP: Logged

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