Film-Tech Forum ARCHIVE: brenkert BX 100 questions

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Posted by Josh Jones (Member # 447) on 03-19-2001, 10:35 PM:

I bought 2 BX 100's and 1 BX 80 this weekend. After I scrounged enough oil from the other 100 head and filled the other 100, I fired it up. two small problems surfaced. The Intermittand sprocket isn't far enough from the case to reach the perfs in the film. The tech that said he last messed with the machines said the movement might be loose because he took them out to look at their condition. How do I correct this? also, when the machine is running, when you look at the intermittant case through the oil glass, it bobs up and down. there is also excessive play in the framing knowbs. How do you tighten it up?

Josh

Posted by Paul G. Thompson (Member # 655) on 03-19-2001, 10:56 PM:

Josh, I don't think the movement is seated properly. It may have just been put in, and that's about it. Go inside the gear case and check the clamp to make sure it is engaged in the movement. Compare it with the other machine you have. This could also be the cause of the bobbing. As far as imtermittent movement mounting is concerned, the mounting and clamping of the movement are both identical. There is a manual on Film-Tech that will show the part I am talking about. Page 40 of the manual, part number X1-1111.

The Framing mechanism is driven by a chain. Generally, the BX-80's and BX-100's are all kind of sloppy. Don't worry about that too much, if it is just the chain that is loose. You can observe that through the gear cover window how sloppy the the chain is. The gear that the chain is wrapped around is connected to X-1142 Vertical framing rod. As you check the chain for sloppyness, look at that rod and see if it is moving. If the rod is not moving and slop is present, don't worry about it. If the rod is moving and the slop appears to be there, then you may have a problem in the compensator. (That big clump of gears). The spline nuts could be worn out, or the rod may be disconnected, as well as the X-1170 Lower Framing link. It is kind of hard to explain this.

Put it this way - when you rotate the frame knob and when the chain slack is taken up, the Vertical Framing Rod should then move. And, so should the intermittent movement. You should also see some of the gears move in the compensator, also.

Posted by Josh Jones (Member # 447) on 03-19-2001, 11:19 PM:

while we are on the subject, the head only has half the oil its supposed to in it. from my understanding as long as the oil is very thin(around 6 or 7 weight) it can be used in the mechanism. someone suggested capella oil. can this be used?

Josh

Posted by Paul G. Thompson (Member # 655) on 03-19-2001, 11:23 PM:

WF 32 could be used in an emergency. But, that is about it - an emergency only! As soon as you get the right oil, give it an oil change.

Posted by Josh Jones (Member # 447) on 03-19-2001, 11:36 PM:

I just went out and fixed it. Thanks for the advice paul. I loosened the clamp and pushed it in a ways and couldn't push any farther. I had left the gate closed, oops. I opened the gate and it slid right in. ran a short piece of film and it runs smooth. If i get anbitious, that machine could be running reels by 2:00 AM

Josh

Posted by Paul G. Thompson (Member # 655) on 03-19-2001, 11:43 PM:

OK - cool. There is an index pin that also seated. The next time you pull a movement out of a Brenkert, you'll see that little alignment dowel. You will also see a little slot on the casting, too. I just wanted to point that out because I have known lots of people who didn't know that pin (or alignment dowel) was there.

By the way - fine shutter timing adjustment is accomplished by a big screwdriver used to turn a mysterious screw which is located to the upper-right of the upper feed sprocket. If I recall correctly, full-throw of that screw is about 9.5 turns. Since the movement was removed and re-installed, the shutter timing is way off.

Center that screw. Then remove your shutter shroud. The shutters ARE NOT (REPEAT - ARE NOT) timed by loosening the set screws that hold the hub on the shafts. The shutter blades are squished in the hubs, and there are two screws that do the squishing. Loosen them to position your shutter blades. Just as the intermittent indexes, the crossover of the shutter blades just occurs - in the middle of the optical axis of the aperature.

Since the gear train may be sloppy, several attempts may be necessary. However, do not hold one shutter blade while you move the other. That will place a burden on the shutter gear and strip the teeth off. Hold it by the hub only as you are positioning the shutter blade.

There is one more thing about a Brenkert you should know - the big screw at the intermittent sprocket is a LEFT HANDED THREAD!!!

Posted by Josh Jones (Member # 447) on 03-20-2001, 07:13 AM:

I ran a reel of film to see how she runs. the intermittant bob or "wiggle" is still there. it is bad enough to see the intermitant sprocket wiggle and shows up really well on screen. what should I do?

Josh

Posted by Paul G. Thompson (Member # 655) on 03-20-2001, 12:04 PM:

Josh, is this on the BX-100 or the BX-60?

Posted by Jeff Stricker (Member # 224) on 03-20-2001, 12:04 PM:

Hi Paul, Your comments about the adjustment just above the feed sprocket from your post above "By the way - fine shutter timing adjustment is accomplished by a big
screwdriver used to turn a mysterious screw which is located to the
upper-right of the upper feed sprocket" got me to thinking about my BX -40, which is a single shutter machine. I've never turned this setting, but just eyeballing it makes me think that it is an adjustment on the amount of engagement with the bevel gear that runs the shutter shaft. Will this provide fine shutter timing adjustment on this type projector? I did all my shutter adjustments by just slipping the shutter blade (when the two "squeeze" screws were loosend, of course) with good results.

regards, Jeff

Posted by Paul G. Thompson (Member # 655) on 03-20-2001, 12:18 PM:

Jeff, that is the fine shutter adjust on the BX-40 as well. Doesn't make any difference if it is a single or double shutter machine, as long as it is a BX-40, 80, and 100.

The BX-60 fine shutter adjust is through a plug in the front of the machine. Brenkert made a special tool for that, but if push comes to shove, a good quality screw driver will work if you are very careful not to jam the screwdriver into a gear or two...

Posted by Paul G. Thompson (Member # 655) on 03-20-2001, 04:02 PM:

For Josh and others who might run into this “Bobbing” problem on a Brenkert Intermittent:

Josh, as it stands right now, the first thing you should do is look at the manual for the BX-100/RCA-100 projector. This is available here on Film-Tech. Go to page 39 and 41, and print out those pages. I am going to be using these pages for the ease of understanding.

1. Remove the gear case cover from the projector. Grasp the movement and see if you can duplicate the slight bobbing by hand. While this is being done, refer to page 41 of the manual and see if you can see any movement in the X-1170 lower framing link as well as the X-3401 framing arm assy. If you can duplicate the bobbing WITHOUT those parts moving, then more than likely there are one or two things wrong. The first possibility is the X1-1111 intermittent holding clamp is not secure. Make sure the X-1114A screw is tight, and check to see if you can move that clamp. If it can be moved, it must be tightened by the intermittent holding clamp screw X-1112. Then tighten the jam nut P-154.

2. Referring to page 39, remove the intermittent unit from the projector. Inspect the alignment dowel p-1194 and make sure it is round. And not hammered flat. (a hex head screw) Referring to page 41, inspect the slot on X-4303 holding assy to make sure it is likewise not hammered excessively.

3. That will exhaust that possibility of the movement bobbing.

4. IF THE BOBBING MOVES THE X-1170 LINK, INSPECT THE SCREW X-1934 AND THE TWO X-1734 SCREWS FOR EXCESSIVE PLAY. If there is excessive play (there should be none to really speak of), chances are the wrong type of screw is being used. If there is no play, check the compensator cluster for a broken part.

5. When the framing knob is rotated, does it rotate too easily? Compare it with your other machine. If it does move too easily, then refer to page 39 and tighten the screw P-1275 until you can feel a normal drag when you rotate the framing knob. It might also be a good idea to remove the intermittent from the machine and see if the intermittent flywheel turns freely without binding.

In the process of these checks, I am confidant you find the trouble.

Bobbing of the intermittent in a BX-60 is caused by the framing sector gear being badly worn out. Providing, of course, the X-1111 clamp is securely tightened, and the alignment dowel is not damaged, along with the intermittent being nice and smooth without binding. The framing sector gear for the BX-60 literally not available in 1980, and therefore, I doubt if it is available today. I have shimmed them up with whatever was handy to remove the backlash.

If you still have the problem after you check all I have mentioned, (which I don’t think you will) let me know, and we can explore some more remote possibilities.

Posted by Josh Jones (Member # 447) on 03-21-2001, 02:12 AM:

Thank Gawd for MSN messenger service! Anyway, it turns out the pin on the lower link was not engaged in the movement's case, basically allowing it to go wherever the heck it wanted. Once I reinstalled it, the framing slack dissapeared and the picture stability is very good. I still have to experiment with gate tension, however.
Thanks to Paul for all his advice. I have to admit, these machines sure do look cool though

Josh