Film-Tech Forum ARCHIVE: Kinoton MP75 E Intermittent

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Posted by Randy Stankey (Member # 64) on 04-25-2012, 03:42 PM:

We have a Kinoton MP 75 E (running 8/70) which is tearing up film. Film tears up below the intermittent while running.

The intermittent makes a sqealing sound, similar to what you would hear if a bearing is going bad. It only makes this sound when the intermittent tries to take a step. Either if the motor is running or if you turn the machine over by hand.

If the machine is running the sqealing sound is constant. If the machine is turned over by hand, the sound is intermittent, only as the sprocket tries to turn.

If you put your finger (carefully) on the intermittent sprocket as it turns, you can feel it vibrate. It occasionally stutters, too.

If you put your hand on the intermittent drive motor, inside the back of the projector, you can feel a vibration there, as well.

This problem has occurred within the last 24 hours.
I operated all day yesterday with no problems. My coworker operated the first few shows today with no problems. It has only occurred during the last show.

The theater is down until this is solved.
The tech who services this theater is not available.

Our assumption: The intermittent drive motor has gone bad and needs to be replaced.

What do you think?

Assuming this is true, what is the difficulty level of replacing this unit ourselves? Both my coworker and I have experience to make repairs on other projectors but have never done something like this ourselves.

Posted by Pete Naples (Member # 761) on 04-25-2012, 05:43 PM:

The short answer is 'no'.

Physically replacing the motor is not too bad, but you need the correct interface, software and knowledge to set it up.

Lovely machines when running correctly, a steadier picture you will never see.

Posted by Randy Stankey (Member # 64) on 04-25-2012, 05:57 PM:

I was afraid of this.

The way I understand, the physical repair is virtually drop-in but the new servo motor has to be calibrated and that calibration takes an oscilloscope and a computer with proprietary software.

The scope I have. The computer I can get. The software and the know-how to use it is not available.

What are the potential problems if the unit is replaced but not calibrated?

Can we do the physical repair and wait for the tech with the software to arrive?

Can the tech talk us through the procedure via phone or e-mail?

Can we do the physical repair and run a loop of test film to know whether the machine is workable?

Posted by Randy Stankey (Member # 64) on 04-26-2012, 05:14 PM:

Got the servo motor changed. Projector is operational enough to present to the school group that's booked for tomorrow but it still needs work.

I think the reason for the failure was because the outboard bearing went bad. We couldn't get the bearing support off the shaft. It was frozen in place. The bearing still turned but it was all "gravely."

The servo motor, the bearing and the intermittent sprocket have all been replaced.

According to the manual, the intermittent sprocket needs to be 42.5 mm from the "main plate" but we can't figure out where the datum line for that measurement is.

We tried from the metal bulkhead of the projector. That wasn't right. We tried from the intermittent support casting. That didn't work either. In the end, we put a piece of film in the gate and aligned the intermittent by eye. That was enough to get it running but it's not perfect.

We need to know where the datum line is to get it right.

The intermittent is steady enough but it's not perfect. At the screen, there is between a quarter and a half in inch of vertical jitter. That's "okay." Just okay. It still needs to be improved. We need to get that sprocket aligned with the gate to cure the weave problem too.

So, how, exactly is this intermittent calibrated?

I have a scope. Do you connect it to the three pins on the bottom left corner of the servo drive control amplifer? Which pins are which?

We have a computer that can connect to the serial port of the drive control. I'm sure I can learn the software well enough to do the job. How can I get it?

The reason I'm asking is because the tech who services this theater isn't gong to be able to come to our location for several days. They are in Vegas.

Judging by the way they talk, they aren't fully versed in how to calibrate this machine, anyway. Or, at least if they are, they aren't talking very much.

If this is going to get done right, we're going to have to do it using our own resources.

Posted by Sam D. Chavez (Member # 1841) on 04-26-2012, 06:19 PM:

Did you call Boston Light and Sound?

I know Cardinal is here in Vegas.

Posted by Randy Stankey (Member # 64) on 04-26-2012, 09:11 PM:

No, but I'll suggest it.

After only having worked there for three weeks, I'm in a tough position. I want things to work right and I want to show that I can make things work right or, at least, find people who can help us get it right.

Today's exercise has helped further that but I think it's still too early to be telling people that they should do things.

The contractor who installed and services the equipment is from Florida. We're in Pennsylvania. Worse, everybody is in Vegas, right now. Monday is probably the earliest time when people will be available to really help out.

I spent some time, today, to study how things work and I think I'm starting to understand. A lot of things seem to work very similar to the way a Christie projector works, only better engineered.

I get the general idea of how the servo drive works.
(I damn well better! I just tore one out and replaced it! [Wink]

)
Given that I have only worked with it for a short time, I think I understand what needs to be calibrated: The step angle and the timing has to stay in sync with the speed of the film and the rotation of the shutter. The principle is the same as a gear driven projector but the servo controller looks at the blanking signal from the shutter to know when to tell the motor to turn. Then it reads the signal from the position sensor on the servo motor to know when it has turned far enough. Instead of gears and cams, it's electronic signals and motors.

The procedures for getting things to come together, I think I can work out. What I really need are the specs, timings and measurements.

Unless I have a 100% working projector in front of me to study, those things are pretty hard to work out without help.

I'll mention Boston Light and Sound, tomorrow, when I go back to work. [thumbsup]

Posted by Scott Norwood (Member # 30) on 04-26-2012, 11:15 PM:

You need to talk to BL&S, Cardinal Sound, or someone else who works on these regularly. There might be someone else closer to you who knows them, but I have no idea who that might be. The electronic Kinotons are unique machines, and your standard off-the-shelf cinema technician is probably not familiar enough with them to be helpful.

Good luck getting useful manuals for these. They seem to be pretty much un-obtainable.

Posted by Randy Stankey (Member # 64) on 04-27-2012, 12:23 AM:

I have a set of manuals for them but they aren't entirely helpful.

First off, they are translated from German and the translation is a bit klunky. Second, the information isn't all there or makes assumptions that you know things and glosses over certain points.

To remove the intermittent sprocket, the manual instructs you to remove the clamping collar from the outboard end but, in reality, there is also another one on the inboard end but the manual makes no mention.

To replace the intermittent sprocket, it says that it should be 42.5 mm. from the "main plate." I assume that means the bulkhead is the datum but, when I tried that, it came our wrong.

Similarly, the manual says, to calibrate the servo motor, you hook your oscilloscope to the control module. It shows where the test points are but it does not explain which test points are which. Okay, so one has to be ground and the other two have to be signal but which is which? It does not say.

Description of the software is just as vague, explaining about phase angle and timing but glossing over the fine points.

In terms of how the projector works, most anybody who knows how to work on more traditional projectors can figure it out. It's just these little details that the average person wouldn't know which will trip you up.

I'll figure it out because the gauntlet has been thrown down.

Posted by Phillip Grace (Member # 2262) on 04-27-2012, 04:03 AM:

Hi Randy. We have one of those machines, but it hasn't thrown that particular problem at us - yet. The intermittent movement has failed completely at least once. (Sounds like a steel tool box being dropped on a concrete floor). If your problem only appears late in the day it might be heat related. Just as a thought, you could check the liquid cooling system. I know the machine shouldn't work if the flow sensor is not rotating, but has it been disarmed? or is the chiller not working properly? Good luck with it!

Posted by Randy Stankey (Member # 64) on 04-27-2012, 10:05 AM:

The flow sensor works. I checked it when I changed out the movement.

It is a little, plastic cylinder spliced in-line with the water supply hose. You can look at it and see the vanes spinning when the fluid is flowing. The vanes do spin.

When the system was first installed, they did have a problem with the cooler. If the level gets too low, the pump churns the fluid, causing it to foam and reduce flow.

One of the first things I was told in training was to make sure that there is enough water in the tank. We check it every morning and we add distilled water about once per week.

I'm pretty certain that the main failure was because the outboard bearing on the intermittent shaft failed. It still turned but it felt like it was full of gravel. I'm sure this was a slow failure that put too much load on the servo motor, causing it to give up the ghost.

After replacing the servo motor, the projector runs much more quietly. In the time I worked there, the intermittent had always made a ticking sound as it turned over. After the replacement, the projector is virtually silent if there is no film in it. Turning over by hand, there is no sound. When running, the only sound is the motor. It's a bit weird to hear a machine run so quietly. I have never heard a traditional mechanical projector run so quietly.

The main issues we have, now are getting the sprocket and gate aligned correctly. I need to find the datum point for that measurement. You can't use the old steel ruler trick because the the feed and holdback sprockets aren't the same dimension as the intermittent.

I'm probably going to change the skids the next time I have the chance. (With proper study beforehand.)

The timing of the intermittent is tolerable. I think most of the steadiness problems are because the trap and sprocket aren't aligned properly. These are my main concerns.

I will keep the intermittent calibration on the back burner until the other problems are solved because it's probably pretty easy to royally fuck the projector if you get it wrong.

Comparatively speaking, trap and sprocket alignment are fairly academic.

Posted by Steve Guttag (Member # 268) on 04-27-2012, 09:06 PM:

Randy,

First off...forget about the O'scope thing...it is really just a troubleshooting aid, not an alignment aid.

When was your projector manufactured? It is important to know if you have an MDE drive or FPS drive...at first glance, they look identical. It will be easiest to see on the intermittent controller (the box mounted on the door that the intermittent motor plugs into.

You will need the correct software and a serial connection to adjust it. Ideally, you will want to go down by the screen and adjust it to perfection so there is no vertical bounce in the image. It can be done from the booth but it is harder, though not impossible. I will often use target film and place a line of the target right on the masking so if there is any vertical motion it will shimmer...one then merely adjusts the intermittent until the shimmer stops or is minimized. You may have to reframe during this process to keep the target line right on the masking/screen transition.

As to the lateral sprocket...don't worry about it too much...the white delrin runners will let you know that you have it right...check it with all three of your traps and verify that the teeth are not gnawing at the delrin...there isn't very much slop there. You have more slop in the perforations than in those delrin runners.

Remember, without reference test film of known quality, you may be trying to adjust for defects in the printing process that created your test film!

-Steve

Posted by Phillip Grace (Member # 2262) on 04-28-2012, 02:14 AM:

We went through a series of faulty chillers, and found out about the flow meter the hard way. (Nobody tells me anything!) As far as the worn bearing is concerned, other than through prolonged use, the machine might have been run with the lower skate tension wound up too tight at some stage. It is quite effective as a clamp, and will also reliably destroy any film in a single pass under those conditions. Before anyone asks, I found that out with junk film while setting up the 3 skates! [Smile]

Posted by Randy Stankey (Member # 64) on 04-28-2012, 10:59 PM:

It's good to know about the scope not being needed. That's just one more thing I don't have to worry about.

Since the 35mm trap is smaller than the 70mm, do you think that it might be a good idea to align it first? Just thinking about it, it would seem to me that the alignment for the 35mm would be more critical. Any small misalignment would be a greater error in comparison to the size of the picture. Thus, even if it is slightly misaligned the 70mm trap would be much closer to being true.

As I said, it was just a thought.

Also, something else I have been thinking about...
If the trap was misaligned before this incident, it might have made some previous operators tighten the trap in an attempt to steady the picture, thus putting more strain on the intermittent and causing it to fail prematurely.

Plausible?

Therefore, getting the trap and sprocket aligned correctly might be solving two problems at once. Do you think so?

Posted by Steve Guttag (Member # 268) on 04-29-2012, 12:07 AM:

I don't think it was trap tension that caused the failure...if the current exceeded parameters (from over tension), it would have shut down.

Again, don't over think the problem...with the power off, spin the sprocket by hand and visually inspect how the sprocket sits with respect to the three traps (guides)...make sure the sprocket is centered with the delrin. You won't have too much slop there to make any adjustments. Again, the teeth are notably smaller than the perforations so they are not going to be able to make much of a contribution to your lateral instability. The 35mm teeth are sized for CS perforations so they have even less affect.

-Steve

Posted by Sam D. Chavez (Member # 1841) on 04-29-2012, 12:03 PM:

Another clue as to whether the sprocket is close to lateral alignment is if the picture fits the aperture. If there is serious misalignment, the end of the frame will be short of the right or left aperture edge.

This presupposes it was correct before.

Posted by Louis Bornwasser (Member # 3063) on 04-29-2012, 05:35 PM:

You check vertical jump on any projector by removing the aperture plate and watching the "jump" on any sprocket hole. This eliminates the possibility of a bad loop. Louis

Posted by Sam D. Chavez (Member # 1841) on 04-29-2012, 07:54 PM:

Kinoton projectors with Delrin runners do not show the sprocket holes unless filed out to do so. Has to do with not melting the plastic parts.

Good advice but not on this projector.

Posted by Tim Asten (Member # 4051) on 04-30-2012, 05:49 AM:

How reliable in general are the E series? I am sure the picture is excellent, but I worry about all those electronics and sensors that keep everything in sync and that intermittant drive unit looks a little lightweight compared to your average Maltese Cross unit, and replacements are not cheap I hear.

Posted by Steve Guttag (Member # 268) on 04-30-2012, 06:07 AM:

In the past dozen or so years we have been putting in the "E" projectors, we have had to replace zero intermittent motors. We have had to change out about 4 MDE controllers, however...these were "repair/exchanged" .

The sprocket hole theory as a gauge of projector steadiness presumes that the perforations in the film were properly made, something proven false. There is skew when the perforators come down and this can cause motion in the image that the projector did not cause. Since most target film will be pin registered, it will appear that the perforations are moving slightly but this is not due to projector malfunction. It is actually the test film which has the defect. Depending on the vintage of 35-PA, one may have more or less motion in the target itself and the target will appear to be steady with respect to the perforations. Having the perforations measured with respect to the edge of the film will show the true culprit.

Posted by Randy Stankey (Member # 64) on 04-30-2012, 11:51 PM:

The sprocket is aligned as well as it can be without taking heroic measures. It is visually centered between the Delrin runners and does not hit anything it's not supposed to.

I already attempted to pull the aperture and look for the sprocket holes but, as mentioned above, that did not work. Instead, I rolled the framing up until the frame line was visible on the screen. Not perfect but, without test film or anything else, that was the best idea I could think of.

Until we can get somebody to come up and PM the projector using the correct software, we can get by.

Something I noticed today. When running, the projector produces a pulsation sound. If you listen, the sound of the film goes, "Brrr, Brrr, Brrr." If you look through the strobe of the projector lamp coming out of the gate to view the top and bottom loops of film as they run, you can see them changing size, ever so slightly. About 1/8 of an inch.

The picture is steady enough that an untrained audience member would not notice anything but, I can see the jitter in the picture and it roughly coincides with the pulsation sound of the projector.

Therefore, I am guessing that the system is in need of adjustment and the MDE controller is trying its hardest to keep the film steady but it is just not able to do the job.

Now that I think about it, the projector made this sound before the parts failed. It wasn't as pronounced but I do remember it.

Posted by Robby Golosino (Member # 6325) on 05-04-2012, 03:31 AM:

We have a kinoton fp50-A model here,for 8 whole years workin here,i have encountered what you have said only twice,i dont know if this helps man,coz i dont have any idea on mechanical structure of your projector...but this may help anyway i think,...have you seen some kind of a head of bolt there that can be adjusted by a flat screw that is holding at the whole sprocket?you may wanted to slowly turn it clockwise or counter to get the right positioning of teeth into perforations.too much pressure pulls the film forcefully,thus making it noisy,and too loose eats up your film between perforation thus making it blurry.hope it helps man,and sorry for my english,im not just used to it...im from philippines by the way..