Film-Tech Forum ARCHIVE: Simplex 5 Star Soundhead pulling damper roller too hard

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Posted by Stephen Frazza (Member # 2320) on 01-16-2005, 02:05 AM:

I have a Simplex 5 Star Soundhead that pulls the damper roller way to hard. The other projectionist told me a belt broke on it so he put a new one on.
But now when it is started the film pulls too hard on the damper roller.There's the 2 pins on the damper roller and the front one has been long gone so i had a screw in there.But the film pulled on it so tight it knocked it loose.Now the damper roller come up and touches the sprocket and then jumps back and keeps doing this.
Also the pad roller has gotten all out of wack so much that i can't even close it, almost like the sprocket is bent or out to far.

So any ideas on where my problem is occuring.Is it an the damper roller, the sprocket or somewhere else?

It is running out to a potts platter but it isn't pulling hard enough to be causing any problems.

Posted by Monte L Fullmer (Member # 2797) on 01-16-2005, 02:38 AM:

Damper rollers are a common thing to bend those two small pins on each side of the mounting frame. I've had to drill out those holes and place a bolt and nut with the bolt end to act as the stop pins for the damper roller's shaft.

Not platter problem, just wondering if he changed out a wrong kind of belt, for 5-star head do now have two different kinds of belts-round and square belts. Square belts are for the older models, and the round ones for the newer (1994 and above)models..

Sprocket speed should be the same between sound head and projector head.

Big thing to watch out is that those belt pulleys, being aluminum, can also wear out, especially in the keyways. I've seen those pulleys have so much play that if one holds on to the sprocket, and the belts off, both pulleys will have rotational play, meaning that they keyways are notched out, and the pulleys have to be replaced.

With film out of the machine, rotate the motor flywheel by hand.Then,look below to where you can see both pulleys, hold on to the outer pulley which drives the head, and see if the two pulleys rotate together when turning the flywheel. And I bet that the big pulley is moving first then the outer (smaller) pulley has to catch up with the big pulley. And with your problem, I bet you have gobs of play, which is also causing your damper problem. For the head and soundhead is slightly out of rotational sync, and even oscillating with this much play.

- a common thing for the 5-star heads.

Good luck - Monte

Posted by Brad Miller (Member # 2) on 01-16-2005, 04:07 AM:

quote: Stephen Frazza
when it is started the film pulls too hard on the damper roller

I will assume based upon this comment that once the projector has been running for 30 seconds this is no longer an issue (which appears to be what Monte was addressing as a problem over the course of the film). A couple of questions...

First, is the sound drum clean and smooth? Look for any rust or buildup of random goo. The film has to be able to slide over that with little resistance during the ramp-up or that will happen.

Second, how about the bearings on the sound drum shaft? When a film tails out, watch and verify the sound drum keeps spinning for at least a minute before it comes to a full stop without any intervention.

Posted by Stephen Frazza (Member # 2320) on 01-16-2005, 07:18 AM:

I'm sorry i should have been more clear, but no even after 30 seconds the damper roller is still bouncing off the sprocket which is making the projector pretty much useless for now.
And I checked the new belt against the old one and I thought it was the same one but i'll double check this.
And Monte I'll check out what you mention about the pulleys when I get in today.

Posted by Steve Kraus (Member # 476) on 01-16-2005, 10:51 AM:

If you thread some junk film directly from lower projector sprocket to soundhead sprocket bypassing the soundhead drum & damper rollers (using whatever path will work and with whatever amount of slack needed) and run the machine briefly does the amount of slack between projector and soundhead sprockets change? Specifically, does it go away and the film pulled taut? If so then you have some sort of speed mis-match which goes back to the pulley issues others have described.

If the slack stays the same then projector and soundhead are both moving film at the same rate and you've got some problem with the resistance of film movement over the drum and you need to look into those issues.

Posted by Mark Gulbrandsen (Member # 72) on 01-16-2005, 12:17 PM:

Just about every case of this has always been failure of the stabilizer bearings typically the rear one because it gets full of belt crap. The stabilizer can't get to its normal film speed because of too much drag. This causes the damper roller to swing all the way to one side or act erratically. Strong does use crappy bearings for the most part.
Best bet is to call in a Technician on this one and have it repaired correctly so you don't end up scratching a print.
Have him disassemble and check the main drive shaft beaings while he is there as well. Since all these are inexpensive bearings replacing them all at the same time would be wise.
Mark @ CLACO

Posted by Michael Schaffer (Member # 1204) on 01-16-2005, 12:56 PM:

I assume by stabilizer you mean the "impedance drum assembly"?

Posted by Steve Kraus (Member # 476) on 01-16-2005, 01:01 PM:

How many Ohms would that be? [Big Grin]

Posted by Mark Gulbrandsen (Member # 72) on 01-16-2005, 01:45 PM:

quote: Michael Schaffer
I assume by stabilizer you mean the "impedance drum assembly"?

Actually the 5 star' s stabilizer doesn't qualify as a true impedance drum. It was an attempt that failed so stabilizer(or attempt at a stabilizer) may be more appropriate. The 4-Stars and RCA's had real impedance type systems.

quote: Steve Kraus
How many Ohms would that be?

Steve, you should know that... [Roll Eyes]

A piece of steel about a foot long would be.... several micro-ohms at most.

Mark

Posted by Monte L Fullmer (Member # 2797) on 01-16-2005, 10:43 PM:

quote: Mark Gulbrandsen
The 4-Stars and RCA's had real impedance type systems.

..that be those fluid filled flywheels that those other two units uses? Very smooth takeoff.

I've always disliked the slow startup to eventual film speed of the solid flywheels that both the 5-star and the Christie uses. - just a small way of cutting corners...

Yes, I forgot to mention the drive shaft's bearings and the shaft itself. Bad bearings can knarl up a shaft pretty bad.

Even check that drive shaft support bearing - the one inbetween the two pulleys, which is mounted in that crossplate.

thx-Monte

Posted by Stephen Frazza (Member # 2320) on 01-17-2005, 04:03 AM:

Well this is the one 5 star we have that uses the older square tooth belts.All our other ones use the newer round tooth belts, and the ones we have for them say goodyear 51-05014 on them so I can tell they are right cause the match the part # in the manual.

The broken belt got thrown out, so I don't have it to match to anymore but this new belt seems to match the other belt still on the motor.The #'s on this new one are useless and don't coincide to any part # and the other belt's #'s have worn off.So I will order some new belts and spares just to make sure.Also the belt pulleys seemed ok but i'm gonna order new ones.

Tried Steve's suggestion and best I can tell they were running at different rates leading me back to my intial thought which was that is was the bearings so I am going to order all new ones with the belts and change everything out.

Thanks for all the help guys and if there is anything else you think I should do or look out for while I have it all apart please let me know.

Posted by Stephen Frazza (Member # 2320) on 03-14-2005, 03:41 AM:

Alright, so I pretty much took the whole projector apart- I replaced every bearing in it, I replaced the belts, I even replaced the pulleys.I put all back together and it has worked fine for over a month.
But then when I wasn't there the other day it started acting up again and the other projectionist had to thread up by bypassing the damper roller to get the show to run.The next day I came in and it ran fine for me.
Then the first show today same thing, I had to bypass the damper roller to run the show.But then it worked fine on all the shows after it.
It seemed like the timing belt was pulling too hard on the tension arm that is between the 2 pulleys,making it click sorta.The belt seemed to be sitting on the pulleys riding them ok.

I mean I changed everything out, every bearing.and it doesn't seem to be a problem with the sound drum, it looks clean and smooth, and those bearings are new also.
So does anyone have any ideas on what i might ne missing here thats causing this to happen randomly for a show here and there.

Any ideas on anything else to look for would be greatly appreciated. Thanx

Posted by Monte L Fullmer (Member # 2797) on 03-14-2005, 04:49 AM:

Now, when you replaced the belts esp. the outer one, did you set the belt tension to where there is a quarter inch of deflection between pulleys when you are pressing down on the belt between any two pulleys then tightening up the tensioner pulley's bracket? This deflection is measured just before the belt begins to tighten up between pulleys.

Did you check the tensioner pulley for worn bearings, since there are two bearings in that pulley assembly? With the belt off, spin the pulley and hear the bearings.

Too loose and the belt teeth will jump over the belt sprockets-like throwing the timing off of a overhead cam car that uses the same timing belt. Too tight, and excessive noise and wear will result.

Sounds like belt tension is too loose- it's jumping a pulley sprocket here and there, thus taking the damper roller too hard again.

-Monte

Posted by Darryl Spicer (Member # 711) on 03-14-2005, 09:54 AM:

I have had issues with that before and had to either replace the whole tension assembly or that tension spring that hooks on the back of the damper roller assembly. Problem was solved. It could still be the issue that Monte described in his post above too.

Posted by Monte L Fullmer (Member # 2797) on 03-15-2005, 01:24 AM:

I must add a closing statement on this to show where I'm coming from on the belt tension topic:

the outer belt is situated in triangle formation with the large sprocket at the bottom and a very small sprocket at the top of the triangle. Plus, the small sprocket on top is driving a bunch of gears, also large to small within the gearcase on a vertical shaft of the Simplex XL series heads. When that small drive sprocket on the outside turns, the intermittent flywheel also rotates about 4 revolutions.

When that large sprocket makes one revolution, the small sprocket is making almost 4 of them. The pull tension that the belt has to make that one revolution from the large sprocket, is quite some pull since the small sprocket also have to turn all of the gears inside with that vertical shaft.

So, with a loose belt having to turn all of that, will jump teeth on the small sprocket being there is so much torque needed to rotate that small sprocket from the start (like moving a car in 3rd gear, not 1st), thus the need of such needed belt tension to completely rotate the system from the large sprocket in a smooth and even pattern on takeoff.

thx-Monte

Posted by Rick Long (Member # 213) on 03-15-2005, 03:23 AM:

It is possible for the projector head to run below speed if the bottom nut on the vertical shaft is not tightened securley.

A quick test to see if this is the problem, thread a loop through the projector and soundhead, leaving a large loop between the projector and soundhead.

Run the machine and see if this loop gets smaller in size.

I had this happen once on a 5-star /1050 combination. It is necessary to remove the vertical shaft to correct this problem.

Posted by System Notices (Member # 2357) on 02-25-2009, 12:36 PM:

It has been 1443 days since the last post.

Posted by Eric Robinson (Member # 2966) on 02-25-2009, 12:36 PM:

While doing some belt research, I noticed the 5 Star manual has a table which shows which belt and pulley combinations you need depending on various motor speeds.

The motor speeds are: 1000, 1200, 1500, 1750, 1800

I am wondering why different speed motors are employed?
Why not just use one motor speed?

Posted by Monte L Fullmer (Member # 2797) on 02-25-2009, 12:53 PM:

Prob due to different line frequencies and voltages that is around the world. Also, for different types of motor applications.

I've seen induction motors used on 5 stars.

Posted by John Walsh (Member # 168) on 02-25-2009, 04:29 PM:

Sync motors for interlocking was an 'optional' motor

Posted by Louis Bornwasser (Member # 3063) on 02-25-2009, 06:40 PM:

1750 more or less in USA; 1800 for 60Hz sysnc.

1500 is 50Hz sync Louis

Posted by Gordon McLeod (Member # 33) on 02-25-2009, 07:44 PM:

Both Western Electric and RCA often used 1200 for there sync systems in the past for 60Hz mains

Posted by Robert Minichino (Member # 3495) on 02-25-2009, 07:57 PM:

1000 and 1200 RPM are 50 and 60 Hz synchronous 6 pole motor speeds, 1500 and 1800 are 50 and 60 Hz 4 pole synchronous motor speeds, and 1750 is 60 Hz 4 pole induction motor speed.

Posted by Mark Gulbrandsen (Member # 72) on 02-26-2009, 08:04 AM:

Of course knowing Wrong's rediclous parts pricing of recently it may very well be less expensive to just use a three phase motor and vari-speed drive unit!

Mark

Posted by Eric Robinson (Member # 2966) on 02-26-2009, 10:29 PM:

Thanks, I always learn something new here.

Posted by Jim Cassedy (Member # 4115) on 03-02-2009, 11:57 AM:

quote: Stephen Frazza
I pretty much took the whole projector apart- I replaced every bearing in it, I replaced the belts, I even replaced the pulleys.

I beleive the technical term for this is a "projectorectomy" [Big Grin]

(not to be confused with a projectoroscopy, which we won't go into here)

Posted by Randy Bowden (Member # 587) on 03-03-2009, 11:08 AM:

I had a theatre with this same problem recently. The projector head was not running as smooth and quiet as it should, so I replaced the intermittent, Problem solved. Sometimes projector head problems can manifest symptoms in the soundhead.