Film-Tech Forum ARCHIVE: CNA 150 / FP-350 Cue Reading Problem

This is topic CNA 150 / FP-350 Cue Reading Problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=007641

Posted by Matt Hollis (Member # 2954) on 11-25-2005, 10:35 AM:

I touched on this problem in an earlier post, but since then it has gotten worse. Here is the setup:

12 Screen
Simplex Millenniums
Strong Super Highlights
CNA 150 Automation
FP-350 Cue Detectors
Strong AP3 Microwitch Platters

Anyways, these cue detectors randomly miss cues all the time. The weird thing is, sometimes they will miss the first cue and then read the second, but on the next show it will be opposite. This has caused problems for some time now. Plus, on a busy set like the 9:30 shows, if a movie on the other end of the building runs out without reading the last cue you get an alarm because the automation thinks it is still in the middle of the movie. We have tried:

Changing all cues
Cleaning out the cue detectors

Any other suggestions?

Here is what I think it may be but am not sure how to cure:

In the older days of the theatre, smoking was allowed in the booth. I believe over time, this smoke has ruined the cue detectors. I am not sure how to fix this though.

I hope you can help me solve my problem.

Matt

Posted by Gordon McLeod (Member # 33) on 11-25-2005, 10:50 AM:

There is a small roller directly under the proximity switchs make sure they aven't gotten bent away creating to big of distance between the prox and the film
Also make the foil slightly longer and also ensure that the film is not bouncing to much due to bad takeup tension

Posted by Ken Lackner (Member # 1002) on 11-25-2005, 11:17 AM:

Depending on what version of CNA software you have, you can try Cue Learn Mode. When in Learn mode, the CNA will memorize the cues, and then you change to Learned mode, and if the CNA does not receive a cue, it will execute it anyway because it has the cue stored in memory. You just have to remember to change to Learn mode every time you put a new print in that house.

I agree with Gorodon about the alignment of that roller.

There have been posts on here before about the same problem. I believe Brad posted another solution. Try searching for it.

Posted by Mark Gulbrandsen (Member # 72) on 11-25-2005, 11:18 AM:

Actually if you loosen up the mounting screws for the detector part you need to space it three film thicknesses fomr that roller to the cue proximity detector head. If these are triple cue detectors than be sure that both the back and front detectors are three film thicknesses. foil shoule be a minimum of 1" long. If this doesn't work replace them, or preferably with Kelmars.... Kelmar's never miss a cue!

Mark

Posted by Brad Miller (Member # 2) on 11-25-2005, 03:25 PM:

For what it's worth...

If the platter elevator has ever "crashed", the roller that supports the film up against the proxy detector is probably bent. The mere design of this failsafe should've said quite blatantly to put the detector on the inboard side, so even if this roller got slightly bent it would still be close enough to read cues, but instead the designers decided to put it on the end of the roller (outboard side) so it would be most susceptible to missing cues and help to create a Dolby Digital dropout, and even an analog lateral shift if the cue was not precisely aligned.

Try using Neumade Aucuta II tape. This is the only tape that failsafe really seems happy with.

Those are bandaids. The real fix is to junk the FP350 and replace it with a Kelmar. Just like Mark, myself and others have said, they NEVER EVER miss a cue.

The "cue learn" mode is just stupid and is just BEGGING for an unintentional cue to be executed when movies are swapped. Don't use it.

Posted by Gordon McLeod (Member # 33) on 11-25-2005, 04:16 PM:

I believe the sensor bosrd could be flipped to make it a inboard cue only
Also it is available with2 prox option to due a 3 cue function

Posted by Monte L Fullmer (Member # 2797) on 11-26-2005, 02:12 AM:

..my two cents in as well...

On the back of the FP-350's you have a terminal board. And the wires, somehow, love to work themselves loose, yet look like they're still attached on that terminal board.

Seen this many a times with these when complaints start up about missing cues. Snug up the screws to make sure wires are in tight and secure.

Yea, just get a damp rag and clean under the 350 to let the LED's do their thing sensing film travel since so much dust loves to stick under there.

Also, BIG thing: if you're running a movie for quite a while, replace your cues since they will tire out and crack (being of aluminum, especially if your putting them on the edge of the film lengthwise instead of across) and when they get to this stage, they lose their conductive properties for the sensors in the 350.

..thx-Monte

Posted by Ken Lackner (Member # 1002) on 11-26-2005, 11:01 AM:

quote: Monte L Fullmer
Also, BIG thing: if you're running a movie for quite a while, replace your cues since they will tire out and crack (being of aluminum, especially if your putting them on the edge of the film lengthwise instead of across) and when they get to this stage, they lose their conductive properties for the sensors in the 350.

I've heard this many times and I don't understand. I thought proximity detectors -- unlike the old style detectors that rely on physical contact with metal sensors -- don't care if the cues are cracked. [Confused]

Posted by Brad Miller (Member # 2) on 11-26-2005, 01:06 PM:

It shouldn't matter, but on the FP350 it just does.

Again I have NEVER replaced a cue no matter how old with a Kelmar cue reader.

Posted by Monte L Fullmer (Member # 2797) on 11-26-2005, 01:19 PM:

Yes, I understand your concern on this. It's basically called "signal strength": if the sensor doesn't pick up a good "signal" from the aluminum-be it of any form of length and being full of cracks which is like a irratic, thus weak signal strength, the sensor will not accept it as such.

And I've seen this happen with the SPECO 3Q units for Christie as well.

-Monte

Posted by Gordon McLeod (Member # 33) on 11-27-2005, 10:39 AM:

the proximity switch used I believe is a capacitive type that use a RF field that the metalic foil disrupts
Cracks in the foil can cause it to see multiple fields
Other types of proximity switchs are optical or inductive/magnetic
optical relies on the reflective nature of a shinny foil and inductive is the disruption of the magnetic field (not good around a mag track)
The best is the optical system that Imax uses that passes the IR right through the film and is blocked by a foil