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Topic: 'rumbling' belt between Simplex 5 star & 1014

Matthew Bailey
Master Film Handler

Posts: 461
From: Port Arthur,TX
Registered: Sep 2000

posted 04-09-2001 03:41 PM

I need help with a flat toothed belt
between my Simplex 5 star & 1014 that
rumbles-not the motor belt-.
The belt is brand new along with the spares,
and I am wondering do I need to adjust
the idler tension on the belt with the
belt installed? I safely and carefully
played with the belt tension with the projector running-assuming the belt is at
proper tension-until the rumbling stops,
but I need to know what to do to get the
rumbling to stop and to get the belt to
properly mesh.

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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999

posted 04-09-2001 04:45 PM

Is this the EXACT same type number belt you had used prior to the rumbling problem? and if so, have any of the pulleys been changed?

There are at least two different tooth pitches for the belts used in the Simplex projectors, and if you use the incorrect pitch belt it will cause exactly the trouble you are describing. I had found this out after ordering new belts for several 1050/5-Star combos and the belts they sent sure looked the same, until they were placed into operation. Same applies to the pulleys, if they were changed for any reason.

Aaron

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Pat Moore
Master Film Handler

Posts: 363

Registered: Mar 2000

posted 04-09-2001 05:28 PM

Matthew; Aaron's on the right track making sure the belt is the right type. Since you state that you're working with the "flat toothed belt" I'm pretty sure you got that base covered.

"Rumbling" is usually the belt being a little loose and the noise is the belt climbing out of the grooves in the pulley and slipping. But it's the old belt that should be stretched, not a new one. Do you get the same sound if you put the old belt back on? Is it noisy on startup or all the time?

Make sure the numbers on the belts, new and old, match. I don't remember the numbers offhand but that's an easy check.

I would say this -- don't EVER try and adjust that belt tension with the projector running. The idler pulley assembly adjusts with two allen screws. Just snug up the belt enough where you can deflect the belt no more than a half-inch.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 04-09-2001 05:35 PM

Aaron's right, First be sure that you have the correct belt for your type of pulleys!!
If you are certain that you have the correct belt and if it just rumbles on startup then you're belt may be too loose. It should have at least 1/2 inch or a just a bit more slack when you press down on the longest stretch of it. Any more and it may be slipping on startup. This would also pull the film taught between projector and soundhead so this would be another symptom.
Also while you're at it go ahead and replace the bearings at least on the main drive shaft of the sound head. I have pretty much made this a policy when I service 5 Stars. If you change belts yearly for your customers as I do, go ahead and change all the bearings out at the same time. This will eliminate all sorts of possible problems in between belt changes. The bearings rely on just the internal grease for lubrication, and especially out here in the land of dry climates the grease dries up quickly. Get bearings with rubber seals for the main shaft, and bearings with shield on one side for the rotary stabilizer. The cost for all the sound head bearings from a local bearing supplier is so minimal that it just makes sense. I just did two plexes full of X-L's and these places were supposedly well maintained but you would have been amazed at what I found. One main shaft was chewed up, and a large number of the bearings were corroded, or the grease dried out. The added cost was only around 150.00 per 6 plex and since you have to take the outer bearing support off to change the belt it's a good time for further inspection, especially if your sound head is more than 3 years old.
Mark @ GTS

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Joe Schmidt
Expert Film Handler

Posts: 172
From: Billings, Montana, USA
Registered: Apr 2001

posted 04-10-2001 04:26 AM

Oh, geez.

When I first saw that soundhead it became another reason why I decided to retire from the business. What a junker! Why, it's made out of tin foil and pot metal!!!

They are all still running? I've heard some crazy stories, one being the projector starts running faster then the soundhead and then squish.

Mark is right, if you have a plex full of these abortions you better have spare shafts and bearings on hand at all times. Good to know you can get standard bearings which will fit from a bearing supply house locally.

Now I will run and hide.

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