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Topic: CP-500 looking for Projector 2

Rick Long
Jedi Master Film Handler

Posts: 759
From: Toronto, Ontario, Canada
Registered: Nov 1999

posted 05-21-2001 12:32 AM

It's been one of those weekends on call. The type where you go to a theatre to fix a fault, and hear the dreaded words "Oh while you're here.........".

The complaint was "the sound drops out during the trailers" - CP-500, Ashely amps, C-E basement reader, ect... Naturally, this was mentioned minutes before showtime.

The feature, "Mummy 2" was run using Dolby Digital, and (as I suspected) some of the trailers were optical only.

A click test proved that there was no sound in either the 04 or 05 formats. After a quick check to ensure that the voltage output to the C-E preamp was correct, (LEDS in the sound-head were on), I opened the CP-500 panel.

It took a minute to register (in my mind) but I noticed that the 661 optical pre-amp was looking at projector 2 (yellow led). Problem was, that this was a platter booth with only one projector.

Powering the system down and pulling and re-inserting the 661 card seemed to clear the fault (now reading projector 1 (red led)).

Has anyone else experienced this problem and what causes it?

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 05-21-2001 01:45 AM

On the back of the unit there is a small jack that looks like a serial cable connector. This is the motor start relay connection. It is supposed to tell the processor which of the two projectors is running at any given moment. If there is only one projector it is supposed to have a plug installed in it that has a wire soldered across two of the pins.
If this connector becomes loose or the wire(s) come undone, the processor won't be able to tell which projector is supposed to be running.

This is the first thing I'd check.

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Pete Naples
Phenomenal Film Handler

Posts: 1565
From: Dunfermline, Scotland
Registered: Feb 2001

posted 05-21-2001 02:54 AM

There was a field buletin some time ago (sorry I forget the nmber), it related to CP500 Random change over in optical format. Basically soem CP500 will change over without being asked, and moreover, the front panel will not display the active projector correctly. There was a mod to carry out the remove software control of change over. That said, I'm pretty sure that it was only supposed to happen when the link that Randy mentioned was NOT fitted. ie a change over house, or where the change over was used to mute.

Have fun!

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 05-21-2001 10:58 AM

The link is for motor sense and that is for digital changeover the opticle is still independent of that

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Pete Naples
Phenomenal Film Handler

Posts: 1565
From: Dunfermline, Scotland
Registered: Feb 2001

posted 05-21-2001 01:05 PM

Ae you are quite right Gordon, the only connection is that the optical change over connections are via the same backplane connector. Either something is shorting and causing our friends CP500 to change over, or the CP500 is doing it all on it's own, without being asked! It does happen, one of my installs suffered from this problem a lot until I carried out the mod in the aforementioned ( I still can't find the number) DOlby field bulletin.

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Pete Naples
Phenomenal Film Handler

Posts: 1565
From: Dunfermline, Scotland
Registered: Feb 2001

posted 05-21-2001 01:21 PM

Seek and ye shall find....

FB217

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 05-21-2001 02:45 PM

FB-217 Comming right up!

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Rick Long
Jedi Master Film Handler

Posts: 759
From: Toronto, Ontario, Canada
Registered: Nov 1999

posted 05-21-2001 04:10 PM

Really appreciate the help guys, thanks.

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