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Topic: Simplex 35 Flaring
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Dave Macaulay
Film God
Posts: 2321
From: Toronto, Canada
Registered: Apr 2001
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posted 01-17-2008 12:35 PM
Aligning the vertical shaft:
There are 2 fixed gears that this shaft has to meet: the bottom drive and the intermittent. The shutter shaft can be moved a bit but this is not an easy job, so unless these three are way off find a compromise, then adjust the sprocket assemblies to suit.
1 - Loosen the upper and lower sprocket support mounting screws (from the film side). Move both of these away from the main shaft, increasing the distance between the drive gears - the top one towards the screen and the bottom one towards the lamphouse.
2 - loosen the vertical shaft bracket screws but leave them finger tightish. Now shift the bracket until the bottom drive gear, shutter drive gear, and intermittent drive gear are all meshing properly with just a tiny bit of "slop" between each gear pair - they shouldn't be mashed tight together but shouldn't have a lot of backlash either. Tighten the mounting screws and check the mesh through several revolutions of the main shaft - a slight bend in the shaft or out-of-round gears can bind the whole works up considerable, you want smooth running and should accept a slightly loose mesh at some point rather than a too-snug mesh. You may find that the three gears are not exactly aligned to mesh equally; Either the intermittent drive gear mesh is too loose or too tight when the drive and shutter gears are correct. So set it up so the tight one(s) are right and the other(s) are a bit loose, again you want to avoid a tight mesh.
The only way to adjust this for "perfect" mesh on all three gears is to mive the compensator (and shutter drive gear). I won't describe moving the compensator as this should be done on a bench by an experienced tech.
Once you have these three gears as you want them, move the sprocket assemblies to get a good mesh on their gears. This is pretty easy and again you want just noticeable backlash through several turns. The gear clearance tends to change when you tighten the mounting screws so check and adjust as required after tightening.
While you have the back off, have a look at what the shutter adjusting knob does. Set it so it's in the middle of the range and then adjust the shutter timing by loosening the shutter hub and turning the shutter plate on the shaft as described in the XL manual. Then you'll have the maximum adjustment available to get rid of ghosting.
If you can't get rid of shutter ghosting, and it seems stable and the knob will take it from top to bottom screen... you may have a "drive-in" shutter. The standard shutter should have 90 degree sections, a drive-in one has larger open sections than metal sections.
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Monte L Fullmer
Film God
Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004
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posted 01-17-2008 07:42 PM
quote: Eric Robinson
This is much easier to do on a Century though.
..which is baby stuff since you're dealing with a different make of projector, no oil issues and shaft layout..no comparison.
Dave's way makes the most common sense in aligning that assembly since you don't want to take out those upper and lower sprocket assemblies since they've got oil seals on the backside that needs replaced if you do.
Ian, to find out if your vertical shaft is out of adjustment: with the back door off, wiggle each gear and see if you've got either none, a little, or a lot of play per each combination steel and fibre gear and if so, then you can see the pattern on how that assembly is aligned - correctly, or incorrectly.
(..side help here ... "Oh, on the paper thickness, you put a piece of paper inbetween the gears, tightened down the set, then roll the gears to get the paper out to get your proper teeth spacing between gear sets. ALSO, there is the possibility that the head and soundhead isn't sitting square on each other, and by loosening the holddown bolts, run the projector and 'hug' the head and see if you can tweak the head laterally to get the two gears in square - which would quiet gear noise down considerably.....")
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