Film-Tech Forum ARCHIVE: Intermittent shoe hard to open

This is topic Intermittent shoe hard to open in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Frank Dubrois (Member # 3042) on 06-09-2007, 12:05 PM:

Well, this one has me confused. Christie M35's. The intermittent shoe gets so difficult to open, that is seems to get locked into place. It sometimes wont open OR close. It's not a gummy or sticky kind of "stuck", but rather a "seized up" kind of stuck. I have tried to adjust the spring by tightening and loosening the hex screw on the side of shoe arm, but that does nothing. When I remove the arm, reset the spring and ball, the arm seems to open and close like new...for about a week or so, then its back to it's old tricks. I took the old ball out and looked at it. It was somewhat pitted and the spring looked a little worn. I replaced both items with new pieces and reassembled the arm. Again, it worked good for about a week or two, then became difficult to open again. Anyone have an idea as to how to fix this for good? There really aren't anymore pieces to replace. The one odd addition to this projector is that we get a lot of horizontal movement of the film. It doesn't seem like the two are related, but anything is possible I guess. The lateral guides seem fine. I even swapped the entire gate/trap assemblies with another projector and picture still seems to shake back and forth.

Posted by Mark Gulbrandsen (Member # 72) on 06-09-2007, 06:03 PM:

As far as the horiz. shake check your turret to see if the lock is latching properly. Sometimes they don't latch all the way.

Why not just replace the intermittent pad shoe as an assembly? Its not that expensive. Sometimes the piece that pivots becomes worn where the ball detents are milled in...

Mark

Posted by Monte L Fullmer (Member # 2797) on 06-09-2007, 10:51 PM:

quote: Mark Gulbrandsen
shake check your turret to see if the lock is latching properly.

..yea, there's that allen set bolt in the latching section of the turret that loves to come out causing the turret not to latch the way it should be...or, one of the screw stops isn't doing it's thing either by holding the turret snug when latched.

Posted by Tristan Lane (Member # 1169) on 06-10-2007, 02:45 AM:

I think if his stop-screw was out of adjustment, his picture would have shifted to one side.

If you have an elusive shaking problem on the Christie, it may be due to excessive vibration coming from somewhere else. I've had a few projectors that were shaking horizontally and I checked all obvious causes. Eventually I discovered that the turret was vibrating much more than the other turrets in the building, and isolated the source of the vibration to a bad plenum blower in the SLC lamphouse. I've also had a bad blower on the bottom of the projector cause the same horizontal movement.

Fell the turret, does it vibrate more than the others? If you apply pressure to the turret, does the shaking stop? If so, start looking for a worn blower. The squirrel cage blowers are normally the cause.

On the Intermittent shoe - Follow Mark's advice and replace the shoe assembly. Although, I wouldn't consider this a cheap part, it's common for the detents to get worn out and require the replacement of the part. To save on cost, just replace the pivot shaft assembly that has the detents machined into it. I believe the part number is 120653-001

Posted by Frank Dubrois (Member # 3042) on 06-10-2007, 02:53 AM:

I will check the turret first chance I get. If I knew the shoe was the problem, I'd replace it. I suppose I could swap it with another to see if the problem follows, but I will check the turret the first chance I get.

Posted by Phil Ranucci (Member # 3820) on 06-10-2007, 02:47 PM:

We've had this problem.It's probably not in the ball bearing/detent part. The shaft that it pivots on gets worn where the 2 setscrews on the bracket hold it in place.Then it moves around and won't close or won't open.I don't believe it is available seperately. Christie said i had to buy the whole shoe/pivot assembly.

Posted by Mark Gulbrandsen (Member # 72) on 06-10-2007, 03:03 PM:

Always if you need a seperate Christie part thats not listed in the manual call projector tech assistance at Christie or ask for Lisa Delgado. Most parts ARE available seperately.

Mark

Posted by Tristan Lane (Member # 1169) on 06-10-2007, 05:34 PM:

FYI, The shoe pivot shaft and the detents are machined from the same piece of metal. Generally, the closing detent will form a ridge around it's rim, causing the ball bearing to become lodged and therefore making the shoe difficult to open.

Over 90% of the shoe issues I've dealt with have been due to this problem, and replacing the shaft fixes it. I guess if you really wanted to avoid changing parts you could try to clean up the detents with a dremel, but you might end up with a less than positive closure when the shoe is in the closed position.

Just replace the part.