Projector Bench

Frank Arnstein’s Pieces of Advice

Re the Cam Tank Module:

I suggest you don’t dismantle the cam tank but lubricate it by dropping light oil in through the special hole that is covered with a small plate and held there by Philips screw that you can see in Pic 1.

About 15 to 20 drops should be fine. This will soak into the felt pad inside to lube the cam inside as it turns.

There is indeed a clutch which interrupts drive to the internals. It is activated by operating the freeze frame lever on the side. Sometimes they get stuck and the clutch won’t move back to the drive position.

Then a small amount of Inox or similar penetrating spray to the shaft will restore the sliding movement of the clutch and it will drive again OK. Make sure it moves in and out when you activate the freeze frame lever.

This problem is due to not being slid on the shaft for a long time and the pulley/clutch parts get stuck on the drive shaft preventing drive.

See if you can free it up by spraying the Inox behind the pulley and work the freeze frame lever till you can see it working as it should.

Let me know how you go.

More on the Cam Tank Module:

The big grey metal washer with the Phillips head screw in it is part of the friction surface that drives the alloy pulley.

Over time, the shaft can get stuck and then it wont slide inside the pulley when freeze frame is activated.

If you spray between it and the pulley the lubricant should get to the shaft and free it and then it will allow the washer to move against the alloy pulley and again drive the cam tank.

Remove the Phillips screw if needed to remove the grey steel washer and get access to the internal drive shaft that has seized and needs lubing to free it again.

Once it is free, spray wash off the oil between the 2 friction surfaces as it may slip if still oily there.

Operate the freeze frame knob continuously till you can see separation occur and recur at the drive surfaces.

Then it should be fine again.

Good luck

The Freeze-Frame Lever:

The axial movement is achieved by the freeze frame plate sliding over and contacting a wedge shaped pulley just behind the 2 blade plate. This sliding plate moves the blade assembly over by riding the wedge and forcing it aside. This assembly slides back and simultaneously cuts the drive to the pulley and which then just spins in the neutral position.

You can easily remove the Philips screw in the centre of the grey drive washer to disassemble the parts to clean and lube the slides. There is a spring behind the blade so it will push forward the blade. Then all will be revealed to you.

As you say, the plate is not flat at the knob end and this ensures the plate does not flop around when installed as it is bent and provides some tension at the sliding screw to prevent slip and rattle. That’s why it needs some lubricant on the slot.

Have a look and let me know how you go.

Fitting of Worm and Fibre Gears:

I believe its true that “A small amount of gear lash is required to prevent abnormal wear.”

This principle also applies to the crown wheel and pinion in your cars differential. There needs to be slight clearance to ensure smooth sliding of the driving and driven gears in both directions. So only tighten the camtank when you can detect this backlash existing between the two gears.

In other words, the two gears should have some backlash which can be seen and also felt by hand when slightly rotating the worm gear both ways to ensure there is some slight gap between the fibre and metal parts. This should ensure no binding occurs, which would soon wear out the fibre gear. Of course some lubricant is also required to ensure free sliding drive.

So when setting this I would use my eye and the feel in my hands. Just make sure there is some slight gap between the two gears so they can slide smoothly over and against each other in both forward and then reverse. No binding is wanted and the backlash should provide the protection we want.

Hope that helps. Frank

Latching of Auto-Threading Mechanism:

To answer I have had to refer to a wrecked Eiki that I have here.

The reason the peg isn’t latching is because the sliding bracket part to the left of it isn’t moving over far enough.

The prime cause is usually the tightness of the shaft that holds the big black plastic auto thread lever on the other side of the machine. It has to be well lubed and fully free.

When activated, the lever should move right over till it contacts and raises the small black plastic piece that directs the film to the sound head rollers channel.

If it won’t go far enough then the shaft is still not free enough and it needs spraying or even dismantling to free the shaft in its hole.

There is a large slotted hole in the bracket to the left side of the peg. This slotted hole should fully slide to the limits of the slot. Make sure its free to slide both ways to their limit. Then the peg will drop into the hook. Don’t worry about the bend in the lever as it needs to be there or it may miss the peg. Lube it all with Inox or similar spray.

Also ensure that the shaft holding the film head roller is free as they often get tight and you get poor sound because it can’t push the film down properly.

It needs to be raised to clear the film when auto threading.

See how you go with that. Make sure everything that should move, actually does move freely.