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Topic: Brenkert Drive Shaft falling out

Barry Floyd
Phenomenal Film Handler

Posts: 1079
From: Lebanon, Tennessee, USA
Registered: Mar 2000

posted 11-07-2000 08:44 AM

I've been working on my Brenkert BX-60's and I finally got the "shear pin" in, but now when I turn the projector on, it will run for about a minute then the main drive shaft will begin to work it's way out of the machine, disengaging the projector from the soundhead.

When replacing the "shear pin", I removed the flywheel from the soundhead (RCA-9030), then took a wrench (counter-clockwise)to the drive shaft to back it out (about 1 1/2 - 2") away from the case of the projector.
When I was re-assembling everything, the drive shaft didn't screw in, it merely "slid" back into place.

The gear "floats" on the shaft, but the entire shaft will come completely out of the machine.

What am I missing??? I got down and looked thru the hole where the shaft came out of.. and you can see clearly all the way thru to the film compartment. All four of my Brenkerts are this way. But, this is the only machine where the shaft actually slides out by itself.

Shouldn't there be something "inside" to mechanically lock it in place?

The end of the shaft that is visible from the film compartment has a threaded hole in the end of it, but none of my other machines have anything screwed in there.

What gives?

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 11-06-2000 09:06 PM

On page 47 of the manual (diagram 9).
Is it possible the taper pin # X-1759 either fell out or broke off? It could be laying in the bottom of the oil sump compartment (bottom of projector).

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John Eickhof
Jedi Master Film Handler

Posts: 588
From: Wendell, ID USA
Registered: Jan 2000

posted 11-07-2000 12:42 AM

If you are talking about the fibre drive gear / shaft that has the oil cup and hex head, it is not threaded into the projector, it is held in by a set screw located at the back of the projector (or side facing lamphouse) You will see two slot head screws in the lower rear of the projector that srew in facing the screen. The upper one holds the intermediate drive gear (with a oil cup & bent tube attached) and the lower one secures the main drive shaft in. The main drive shaft has a tapered flat spot on it (if you pull it out, you will see this) The setscrew holds against this flat spot to adjust end play.
Hopefully, while twisting the shaft, you did not shear the setscrew off, if so, pull the shaft all the way out and insert a magnet to remove pieces. These set screws are long fillister head screws. See diagram #1 in your manual, the screw is P-1301 Good luck!
If you do not have a manual, I can supply one, email me. John

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Jeff Stricker
Master Film Handler

Posts: 481
From: Calumet, Mi USA
Registered: Nov 1999

posted 11-07-2000 01:19 AM

Barry, John has hit the nail on the head. There should be a flattend area on the drive that the set screw presses on.

That brings to mind another question. One of my drive gears has a "thrust bearing" on it. This is located at the end of the shaft between the oil cup and fibre gear. On the other there is just a flat washer. Any thoughts on this? I notice that the washer gets slightly warm after running a reel of film (it's getting proper lubrication though)...The one with the thrust bearing is cool. Brenkert manual doesn't talk about this.

Jeff

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John Eickhof
Jedi Master Film Handler

Posts: 588
From: Wendell, ID USA
Registered: Jan 2000

posted 11-07-2000 11:22 PM

Jeff, as normal practice in over-design,
real-crappy-apperatus (RCA) was known to over build things! With one major exception...the
projector drive gear assy. RCA / Brenkert found that the Brenkert machines needed more torque to get up to speed than other makes,
ie: Simplex / Century, Etc. Thus, the original projector drive assy (which you will find listed in the 9030/9050 book, not the BX-60 book) it is assembly #MI-9129-A
And includes the fibre gear, shaft, bearing, thrust washer (bearing race) steel pinion,
oil cup and screws for fibre gear. The thrust bearing is not listed as a seperate part. I may have a used bearing assy w/race if you are interested, please email me, I will check stock. I recommend it highly as it will reduce friction on start up and during
operation, thus lessening wear on the gearbox in the soundhead.

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Barry Floyd
Phenomenal Film Handler

Posts: 1079
From: Lebanon, Tennessee, USA
Registered: Mar 2000

posted 11-08-2000 07:43 AM

I got home last night... late. All of the major streets in downtown Nashville were closed (Something about a Presidential election or something).

I re-alligned the shaft - so the oil cup was straight up, tightened down the "set screw", and turned that puppy on. It worked !!!!

Comparing this machine to the one sitting directly next to it... this one is still a little harder to turn over by hand. It will turn over by hand, but not like the other one. The 1st machine turns over as smooth as butter - with no effort at all... almost as easy as my XL.

Since this machine has been sitting idle for almost 3 years, I removed the gear cover and sprayed the gear train with "Brenkert Projector Oil" - replaced the cover, and let it run for about an hour.

It is quieter now, and everything seems to be running fine, although it is still a little tight.

Thanks to all of you for your help!!!

Next Project: Locate the wiring diagrams from the sound head to the processor and exciter supply

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