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Author Topic: Timing belts on 5-Star Soundhead: Wolff King Morrow Master Film Handler Posts: 490 From: Denton, TX, USA Registered: Feb 2004 posted 03-13-2005 01:53 AM                        Its about time I replaced the belts on these guys, but the manual doesn't give any instructions on the procedure. Has anyone written a guide for this? I opened the back plate cover to have a look. There are two belts (15mm round tooth 60Hz). That's about as far as I wanted to go without formal instruction. Mucho appreciated if anyone can give a walk-through on this!  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 03-13-2005 02:33 AM                    The first one is pretty simple. Pretty much slide the old one off and put the new one on. The second one is a little more involved. On that one you have to remove the two hex bolts from the bearing plate and swing it out of the way. Sometimes the belt tension arm on top of the plate likes to hit the main frame of the sound drum assembly preventing the plate from swinging far enough to allow the belt to pass by it. So you have to loosen the arm and move it forward so it will not hit the main frame. If this happens I have found it easier to access if you remove the fly wheel for the sound drum. Once you are able to get the belt past the plate you will need to move the belt guard out of the way on the front of the sound head. Just remove the two bottom screws and swivel it out of the way. Now just work the old belt off the pulley and work the new belt back on. Sort of like trying to get a chain back on a bike without taking the tire loose. After you get the new belt back on put the plate back in its position and put the bolts back on and tighten. If you had to loosen the arm, just adjust it back to it's position with the second belt in place then tighten the bolts for the arm down. Make sure you leave about a half inch of play in the belt. By this I mean once you have the belt on and the tension pully pushing against the belt there should only be about a half inch movement in the belt inwards or outwards. If you did not have to move the arm then you should be able to slip that second belt on without any problem.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 03-13-2005 02:58 AM                     quote: Wolff King Morrow Its about time I replaced the belts on these guys ..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  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 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.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 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  |  IP: Logged Wolff King Morrow Master Film Handler Posts: 490 From: Denton, TX, USA Registered: Feb 2004 posted 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.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 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  |  IP: Logged Wolff King Morrow Master Film Handler Posts: 490 From: Denton, TX, USA Registered: Feb 2004 posted 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!  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 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.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-18-2005 06:47 PM                     Steve, Cock, Shaft...... man, please watch your wording there..... . Mark  |  IP: Logged

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