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Author
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Topic: GS1200 Take Up and Rewind Motors
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Graham Ritchie
Film God
Posts: 4001
From: New Zealand
Registered: Feb 2006
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posted August 23, 2006 09:08 PM
After reading Kevins experience regarding the relays, it brought back memories of a problem I had with the take up about 3yrs ago. I should mention I am not an expert on projectors, far from it! One night the take up juddered to a halt it had been playing up for a while but this time it finally threw the towel in. ![[Frown]](frown.gif)
After removing the projector rear cover I unsoldered the two motor wires, next I removed the motor assy from the frame, and removed gears and bracket thats attached to the front of the motor. I scribed a reference line along the motor casing, I then removed the two screws from the motor end plate and carefully dimantled the motor.
Basic parts are front plate, motor casing, the rear plate with its brushes, and the motor armature, at the end of the armature is what they call the commutator which is made up of segments, and its on those segments that the two brushes run.
I next cut narrow strips of 600 grade wet and dry paper you use for car body work.
Using those strips I carefully polished out the wear on the commutator, I then used a thin bladed knife "stanley" and very gently used it to scrape out any deposits from between the segments, finishing with a good wash of CRC Electra clean including the brushes etc.
Next I cut the ends of two cotton buds and using the cotton buds compressed the brushes, and slid the back plate and its brushes carefully over the commutator.
Using a strong magnifying glass I inspected the brushes, looking in particular to see how much spring tension was still remaining, and that the springs had not bottomed out luckily this was OK .
I then slid the complete armature with the back plate through the motor casing and through the front plate bearing, and using my reference line to align all the motor parts I refitted the two screws.
I also carried this work out on the rewind motor, in doing this I was surprised to find that this motor was far more worn than the take up. I guess this is due to the fact that when you press play the rewind is turning faster and at a constant speed than the take up.
One thing I did not do is to put any lubricant on the motor bearings, the reason for this is that in time it can work its way onto the brushes, any lubricant mixing with deposits will act like a cutting compound and excessive wear could occur, the motors were put together clean and dry.
Well as they say the proof of the pudding is in trying it, I ran the projector with a empty 800ft reel and using the reel I tried to make the motor stall, Next was to feel through the reel if the take up was smooth everything went well ![[Smile]](smile.gif)
I have had no problems although making a statment like that is tempting fate! I feel that cleanliness and good contact between those brushes and commutator is critical for trouble free running.
Well thats my wee story!
Kev could you please help me with a few queries I have, one are the take up and rewind motors interchangable, and during the production run were there changes made the reason I ask is that initally I fitted a new take up motor without success due to the excessive speed and torque I would still like to use it at some future date but am not sure what I am dealing with. thanks.
Graham.
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