Film-Tech Forum ARCHIVE: Loose winding on LP-270

This is topic Loose winding on LP-270 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Richard Greco (Member # 2032) on 12-19-2003, 11:05 PM:

I seem to be having a problem with 3-4 of my 8 platter systems.
I thread normally, but the take=up isn't nearly tight enough. I am able to push the film on the edge and see it move.

When I move films, they are so loose, they almost fall out of the brackets..

Any ideas on how to tighten tension on the LP-270?

I did notice much dirt on the elevator roller assembly.

Posted by Brad Miller (Member # 2) on 12-19-2003, 11:13 PM:

You've got to tell us what vintage LP270 you have for us to tell you the cause and solution. On the takeup elevator that moves up and down, are there 2 rollers, or just one?

Posted by Richard Greco (Member # 2032) on 12-19-2003, 11:15 PM:

Sorry Brad, It is a one roller elevator system.

Posted by Matthew Peters (Member # 1495) on 12-20-2003, 12:18 AM:

Could you possibly add some weights to the take up elevator?

I’m not sure why, but I think one of our LP-270 has some small weights on it.

It could be there to ensure it doesn’t "Stick"

Posted by Bruk Mogos (Member # 2043) on 12-20-2003, 04:28 PM:

Hey Richard it looks like the rubber roller on the platter motor shaft extension is worn out, so try replacing the shaft extension since you can't replace the rubber by itself. if you don't have any replacement shafts try taking one out from a working platter and see if the problem is fix. If not try threading to only one roller the one on top since there are 2.

Posted by Tim Reed (Member # 137) on 12-20-2003, 04:32 PM:

Make sure the trolley tracks and the (twisted) variac control rod are absolutely clean. That assembly must slide unimpeded.

Posted by Brad Miller (Member # 2) on 12-20-2003, 04:50 PM:

Tim's got the fix. Additionally I would recommend you put a slight bit of oil on some paper towels and thouroughly wipe the two rods of the elevator so you leave a light coating of oil on them.

Posted by Bill Langfield (Member # 818) on 12-23-2003, 09:54 AM:

Excellent question Richard, one I have been meaning to ask for while.

Tim's solution, that is make sure the shaft is clean and has lick of lube on it, a good starting point.

Bruk's one is worth looking into, but Ive never seen the motor to plate rollers wear to a point, that it would have an effect on Speco. (On the other hand, CNR's are a nightmare)

Matthew's, idea has merit, but could be dangerous for two reasons,
#1 the weight should be mounted in such a way it does not foul the roller dropping all the way down to the micro-switch cut off, in the case of film break. Could be an idea to use those weights used on the pay-out wrap-around safety elevator.
#2 (dont make the weight is too heavy) Two of our platters are the double roller elevator type, and once I only went around ONE of the bottom rollers (because years ago a tech suggested, 'Hmm that might get a tighter wind.') DONT DO IT. I think it was the last 007 movie, and it wrapped that tight that the whole print arched up, and looked like it was going to implode, so I pulled it off onto 6000's then re-plated. Would have hated to see what would have happened if I removed the centre ring, if that was possible, I guess missing that roller was the same as doubling the take up tension, but it looked more like 10 times.
I'll try increments of weights on our older Speco's.

I look farward to more idea's, and I'll post my results, but for double roller platters only, as the single roller platters only need Tim's solution, as far as Ive found.

Regards, Bill

Posted by Brad Miller (Member # 2) on 12-23-2003, 11:25 AM:

Bill, the idea on the double roller elevator is to only skip the center top roller, not one of the rollers on the elevator itself, thus during operation the film would look like a capital "U", not a "V".

Posted by Richard Greco (Member # 2032) on 12-23-2003, 10:12 PM:

Guys, I tred the cleaning and lube on the worst one, It helped a little but is still very loose when moving prints.

I unfortunately can't touch anything in my booth that requires me disassembling anything due to the fact that my manager will hang me if I do. She doesn't trust me enough to do that yet.

Posted by Brad Miller (Member # 2) on 12-23-2003, 10:13 PM:

Does the elevator move up and down easily on the rods? I am wondering if possibly one is bent.

Posted by Tim Reed (Member # 137) on 12-23-2003, 10:21 PM:

After you check that, you might want to look at the sprockets on the projectors. Pulled sprocket holes, however slight, can cause the same effect. Although, since you're having the same problem on numerous units, I'd bet the whole problem is dirt on that takeup assembly.

Posted by Richard Greco (Member # 2032) on 12-23-2003, 10:28 PM:

On the particular projector that is the worst, The elevator does move smoothly with no problems.

I can check the sprockets if I know what to look for.

Also, I informed my manager and she said she talked with our tech and he said it can't be fixed. I truthfully think it can be, but she doesn't want to bother with it.

Posted by Tim Reed (Member # 137) on 12-24-2003, 11:05 AM:

Look at the film edge-on and see if you find damaged perforations. Compare it with a new piece of film if you have to. If it has pulled sprocket holes, you should be able to see and/or feel a slightly-raised area on a leading edge of the sprocket hole. If they are damaged, then you might have hooked sprockets in the projector, or something that's pulling too hard on the film. If that's the case, then it will be a process of elimination to find the offending part(s).

Incidentally, if you have platters that are fine, and a few that were fine but are now winding loosely, then it IS something that can be fixed.

[bs]

- can your lazy tech.

Okay, on the moving smoothly... they can feel okay to you, but still be not smooth enough for the film. Clean thoroughly with isopropyl alcohol (don't just wipe it down with a rag), and then apply the thin film of oil. The inside of the nylon bushing that the the roller rides up and down on also has to be like-new clean. If you haven't cleaned inside there and gotten all the gunk out, it's not clean. And to do that properly, it probably should be disassembled.

Is the nylon bushing, or the trolley rollers, worn possibly? That's something to look at.

The whole assembly not only has to be spotlessly clean, but it has to be smooth under its own weight. I know it might feel smooth to you, but still have problems. Just a very slight mechanical resistance can be enough to cause a loose wind. It has to be absolutely clean and in proper alignment (so there are no "hangups"). Try hanging a weight on the arm for a show. If that tightens the wind, then the takeup assembly is the problem.

Posted by Kelly Skaggs (Member # 1780) on 12-24-2003, 08:48 PM:

When you move the print to a platter that winds tight does the print still wind loose or tight? If it still is winding tight I bet you have a sprocket pulling and causing some damage.