Film-Tech Forum ARCHIVE: Are TA-10 Film Presence and Film Motion reliable functions?

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Posted by Gary A. Hoselton (Member # 3447) on 11-29-2019, 12:20 PM:

For some years I’ve been using two Component Engineering TA-10 Theatre Automation control boxes to operate two Simplex XL’s atop 5-Star soundheads in changeover mode, using only the Motor, Lamp, and Douser bypass switches and never turning the TA-10 on. I’ve mounted the TA-10’s on the front wall, one in front of each operator position, such that I can’t reach one from the other. I’ve long been intrigued by the Film Presence and Film Motion detectors on the FM-35 Film Monitoring System, attached under the soundhead, as a way to automatically close the douser and remove power from the motor in the event film breaks or the tail runs out of one projector when I’m busy with the other projector. Finally, I’ve found some spare time this Thanksgiving Day to think about it.
It appears that the TA-10 is designed for unattended single projector operation using a platter. With a TA-10 turned on and running a 30sec commercial thru its projector several times, at end of film motor shuts off and douser closes. However, seven seconds after depressing START, the douser opens (and closes on the other projector), which interferes with my manual changeover. Reading the Operators Manual, looks like I’d need to cut the run on the motherboard to Douser Close relay coil, and then wire from Event 3 Intermission thru an Output relay back to actuate Douser Close relay only at film break/end of film or loss of motion. Regrettably, this manual doesn’t include a schematic diagram of the motherboard, so I suppose I’d have to remove one and trace a bit—no fun.
Questions:
1. Are the Film Presence and Film Motion functions reliable enough to run all the time? Any surprises?
2. Is there an easier way to use these functions in changeover mode?

Posted by Randy Stankey (Member # 64) on 11-29-2019, 02:56 PM:

The FM-35 also has metal detecting cue sensors that are used to trip certain functions in the TA-10 or other systems.

Place a thin strip of metal foil tape either along the inboard edge of the film, the outboard edge or exactly in the center.

These foil strips only need to be about the length of one frame of film. For multiple, stacked cues they need to be about four frames of film apart.

You may combine inboard, outboard and center cues to achieve up to 7 discrete cues, depending on how your automation handles things. (There are 8 possible cue states if you count "No-Cue".)

The TA-10 does IB, OB and C cues, by itself. You'd have to tinker if you wanted to make it recognize IB/OB, IB/C, OB/C or IB/C/OB.

Three cues is plenty for 90% of the setups out there.

They are often used for "Lights-Up," "Lights-Down," and "End-of-Show" cues but there isn't any reason why you shouldn't be able to make them act as automated changeover cues.

I found the FM-35 to be quite reliable if they are kept clean.

If you use a soft brush of a Q-Tip to clean off the little windows underneath the horizontal plate, they'll operate without any trouble. If you let them get dirty, they'll start dropping out. (Not detecting film when they ought to.)

I have not ever had trouble with the metallic cue detectors, themselves. Just make sure that the foil cues are large enough.

When I first started, we were told to use very small cues. People used to blame the detectors when they didn't recognize cues. Later, I looked into the problem with the manufacturer and I learned that the cues need to be about as long as a frame of film to be 100% reliable.

I started doing that and never had a missed cue, since.

Posted by Brad Miller (Member # 2) on 11-29-2019, 06:48 PM:

The only problems I ever had with them was:

*The angle of exit off of the failsafe could sometimes make the failsafe think there was no film in it, and as such would shut the machine down. For platter use this was nothing more difficult than adjusting the return roller forward or backward a bit. This was a very rare thing though.

*The failsafe cannot properly run bleach bypass prints through it without being flaky on its sensors. A couple of examples that comes to mind are Seven and Payback.

For what you need a simple microswitch failsafe is more than suitable, but the FM35 should do just fine though.

Posted by Gary Wachter (Member # 5833) on 12-02-2019, 01:56 PM:

Keep a careful watch on the FM-35's tiny rollers. They have been known to quietly seize up and scratch the edges of the film.

Posted by Peter Hall (Member # 695) on 12-05-2019, 08:56 AM:

Hi Gary
The motion and presence detectors on the FM35 are pretty good however when they get old they can show phantom presence due to residual magnetism in the FM35. I had a client who used to remove the blocks and put them in a dishwasher, which worked well.
Re changeovers, we have done this by starting the second projector in interlock mode and applying a OPEN cue to the film. Lace up on 7, cue the START button off a tape on projector 1 and the cue on projector 2 will open the douser. I am assuming that the two shutters are interlocked together - if not you will need to put a STOP cue somewhere. It took a bit of playing but we did this a lot on sites with two projectors and non turrets (eg DP70, DP75s, early FP20s, Westars) and they wanted to run the adverts and trailers on a separate machine then change to the feature in scope.

Posted by Randy Stankey (Member # 64) on 12-06-2019, 12:27 AM:

Any problems with cue sensors malfunctioning or rollers seizing that I have ever seen can be taken care of by regular cleaning.

Clean them with a soft brush every day.
Use alcohol on a lint-free swab every couple-few weeks.
Take them apart and clean with Formula-409 every once in a while.
When reassembling, check for worn or damaged parts.

In every booth that I maintained, if they were cleaned like they are supposed to be, there were very few problems with FM_35s.

Posted by Scott Norwood (Member # 30) on 12-08-2019, 06:54 PM:

I was once told that there was some issue with early models of these and being able to detect film motion with B&W prints (which explains Brad's issue with bleach bypass prints, too). I have only personally worked with later versions, which work fine with both B&W and color prints.

Sometime in the mid-2000s, they switched to slightly larger rollers, which eliminated some film scratching problems that the earlier ones had. This is an easy upgrade if the rollers are still available.