quote: Wolff King Morrow

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Its about time I replaced the belts on these guys

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..that's a-easy one:

1- take off the flywheel with an 1/8inch allen wrench. One of the holes has the allen setscrew. (why of the two holes is for flywheel balance requirements. If you only had one hole, the flywheel will never be in balance) Remember the distance in which the flywheel is mounted on the scanner drum's shaft as how far the flywheel is from the end of the shaft.

With the flywheel off:

2- You'll notice that the outer belt has the belt tensioner pulley, which the two set screws must be loosened with a 9/64 inch allen to slide in the tensioner bracket. This will loosen the outer belt for removal. (this is the easiest part..not it gets a little more difficult, but still not bad...)

3-With the outer belt off: you'll see the outer belt sprocket. Take the same 1/8inch allen and loosen the setscrew that is directly above the drive shaft key and this sprocket slides off. Just be careful in not losing the sprocket key that locks the sprocket on the shaft. Remove this sprocket.

4- Now, you'll notice the main bearing and support bracket. On the main bearing, there is two setscrews that fastens the bearing on the main sprocket drive shaft. The allen's would be smaller than the 1/8inch allen, more like 3/32nds. Loosen these two allen setscrews. Then the bearing support bracket must come off as well. This is held on by two 3/16th allen screws. Remove the screws and the bracket with bearing will slide off of the drive shaft.

5- This exposes the inner motor belt driven sprocket. Take a 7/16inch box end wrench and loosen the motor mount bolts, and slide the motor inwards to loosen the belt. Take off the front pulley flywheel cover that is mounted on the front of the 5-star platform. This allows the belt to be removed from the motor pulley. Belt then comes off of both pulleys.

6-Install the new motor belt over the big pulley, and then slide the belt over the motor flywheel pulley. Then slide the motor back until the belt has enough tension (not fanbelt tension) where there is a quarter inch deflection when pressing down in the center part of the belt. The tighten up the 7/16 motor mount bolts.

7- Remount the bearing support bracket in reverse order as above. When tightening down the bearing on the drive shaft, make sure that one of the lockdown setscrews is positioned on the flat spot of the driveshaft.

8-Remount the outer sprocket as above. This will be a trick since there is that key to put on the shaft first before mounting the pulley. place the keyhole at "12 O'clock" position to aid in holding the key while sliding on the outer pulley. Leave the pulley loose on the shaft. (I'll explain later on why this being loose for now.)

9-Put the belt on over the three sprockets - the projector drive sprocket, the tensioner pulley, and the outer drive sprocket. Then, push the tensioner pulley bracket towards the console, until the belt has the same 1/4 inch deflection, then tighten down the bracket on the bearing support bracket. (Now, here is my explanation of my reasoning above:) Look from above and to the right on the drive sprocket and see if the belt is aligned straight through all three sprockets, then one can slide the drive pulley in or out to match the other two pulleys. When aligned, lock down the drive pulley.

10 - with all assembled, flip on the motor switch and watch the belt action for final alignment and tension readjustments. If these two requirements are met, turn off the motor, replace the flywheel to the mark that it was originally set (not to far in, or it'll rub against the wiring harnesses to the right, or not in far enough and it'll rub against the cover..) and lock down setscrew. Do another spin test on the flywheel the replace cover.

Replace the motor sprocket cover on front of "5-star."

One small tip: while all of this is torn apart, spin both shafts - the scanner drum shaft and the main drive shaft. These shafts are loaded with bearings on each end. Any roughness or whirring means a bearing/shaft replacement.

Now, another side tip: Okey, you have this all put together. Turn on the motor, look down below. Is there any belt oscillation? If so, the outer pulley is worn where the two pulleys aren't turning together at the same time. They keyway(s) of both pulleys could be worn and these sprockets also needs to be replaced.

Good luck - and have FUN and get real greasy! - Monte
 

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Posted by Darryl Spicer (Member # 711) on 03-13-2005, 03:05 AM:
 
Like damn Monte I never had to go through all of that to get the belts off and on. All I ever did was what I wrote in the post before yours.

But I see your point if you want to check the bearing and stuff.
 

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Posted by Monte L Fullmer (Member # 2797) on 03-13-2005, 03:16 AM:
 
Hi Darryl-

True on what you said, but he has the newer "5 star" head that uses the round belts, and with round belts it isn't as easy as doing flat belt changeouts.

Strong almost completely redid that working side with the round belt conversion - by adding a much larger bearing support plate and larger bearing, where this has to be taken off for the inner belt replacement.

Yes, the older "5-star" that uses the flat tooth belts is much easier and your descript fits this pretty close on what I do on the flat belt replacement.

This instructional layout that I've posted is the actual way to change out belts on the "5-star" which I've been taught by Strong representatives when this head came out in the mid 80's -to replace the SH-1000, or the commonly known "4-star."

Later, I was only slightly revised on my teaching with the introduction of the round belt conversion in the mid '90s when shown of the larger bracket and bearing setup.

thx-Monte
 

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Posted by Wolff King Morrow (Member # 2226) on 03-13-2005, 04:09 AM:
 
Thanks a bunch, guys!

I will print out your steps so I can carefully go over each one while doing it.
 

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Posted by Mark Gulbrandsen (Member # 72) on 03-13-2005, 09:13 AM:
 
Wolf,

No one mentioned that you be sure to have the correct belt, square tooth, or round tooth version before you take em apart! Conform which one you have forst...... They are also the least expensive to procure at a local bearing supplier such as Motion Industry.

Mark @ CLACO
 

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Posted by Wolff King Morrow (Member # 2226) on 03-13-2005, 05:06 PM:
 
I made sure it was round tooth 15mm 60 Hz. I hear the square tooth are much older in design. Mine were installed in 2000.
Thanks!
 

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Posted by Steve Guttag (Member # 268) on 03-18-2005, 05:59 PM:
 
No one also mentioned not to tension up the belts until they reassembled everything and had the bearing bracket resecured. The last thing you want to do is cock the shaft by tensioning a belt before it has all of its support. In fact, a serious design flaw of the 5-star is that the outer belt is only supported on 1-side...which has lead to the current bearing that is massive and not as likely to allow the shaft to cock as it goes through it.
 

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Posted by Mark Gulbrandsen (Member # 72) on 03-18-2005, 06:47 PM:
 
Steve,
Cock, Shaft...... man, please watch your wording there..... .

Mark
 

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