Film-Tech Forum ARCHIVE: CP500 Dolby Digital Strange Problem

This is topic CP500 Dolby Digital Strange Problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Lyle Romer (Member # 1266) on 10-20-2006, 09:12 PM:

A CP500 stopped playing Dolby Digital. Looking at the "internal DA-20" the error rate was "F" and the "corner found" LEDs were flashing randomly. When you cover the lens on the reader, the "corner found" LEDs just keep flashing randomly and don't turn off like they would normally do. Tried resetting the processor to no avail. Any suggestions on what might cause the random flashing? Some kind of software corruption maybe?

Posted by Robert Minichino (Member # 3495) on 10-20-2006, 09:44 PM:

I'd first think it might be a reader or cable issue causing random video signals to be detected. Just my $0.02.

Posted by Demetris Thoupis (Member # 833) on 10-21-2006, 01:38 AM:

CAT 670
Video Aquisition board. If this is a multiplex and you have another CP500 available try swapping it. I recall once it gave us a big hustle as everything was set up ok but we could not get Digital playback. Swapped that card and Walla!
D

Posted by Frank Dubrois (Member # 3042) on 10-21-2006, 01:50 AM:

I would suggest the same....Video Aquisition board. When you cover the LED the lights dont change what their doing? Do they go out at all when you cover the LED?

Posted by Lyle Romer (Member # 1266) on 10-21-2006, 08:53 AM:

When you cover the reader LED, the "corner found LEDs" just keep randomly flashing. It seems to be 2 LEDs at a time in each set. I was trying to notice a flash pattern but it seems pretty random.

Posted by Paul Carey (Member # 2241) on 10-25-2006, 08:21 PM:

It may not be this, but try checking the power supply to the reader. We had a really annoying problem with our system lossing Digital randomly. After checking almost everything, it turned out to be a duff transfomer which had a fluctuating voltage which was screwing the reader up.

Paul

Posted by Chad M Calpito (Member # 3736) on 10-29-2006, 04:38 PM:

Currently, I also have a strange problem with the CP500 unit in Theater #1. The Dolby Digital Processor doesn't switch to Dolby Digital. When I press the Dolby Digital button, the system says "Not Ready". This has happened with two different prints. So, I can't quite figure it out. The one in Theater #10 works great, which is the same unit. I tried the other selection, Dolby A-Type with a volume setting of 6.5 so customers won't have to complain about the sound being too low. The movie I am playing in #1 is "The Prestige". So, any ideas would be helpful.

Posted by Louis Bornwasser (Member # 3063) on 10-29-2006, 05:11 PM:

First of all, use Dolby SR as a back up, not "A" since that hasn't been used in 20 years.

"Not ready" could be any problem in the DA-20 part of the processor or any part of the reader & cable. Louis

Posted by Frank Dubrois (Member # 3042) on 10-29-2006, 10:37 PM:

You might want to check the voltage in the readers LED. My past experience has been if it wont switch into digital, its because the reader isnt able to read the print correctly. Could be LED, could be reader alignment. When the print is playing, do you see the 32 green LEDS on and steady? (I think theres 32..4 rows of 8 or possible 4 rows of 6) I dont remember. If you can't get the processor into digital, my guess is that those little green LEDS are blinking and flashing like crazy....at least, thats been my experience.

Posted by Steve Guttag (Member # 268) on 10-30-2006, 09:48 AM:

Frank is probably much closer on this one especially if Dolby-A is a better alternative.

If the LEDs have faded (as they do the moment they are turned on)...then the Digital audio will fail to a reduced level analog. The Dolby SR circuit will treat this reduced level more like noise than signal and further reduce the level and introduce "pumping" to the sound.

Steve

Posted by Chad M Calpito (Member # 3736) on 10-30-2006, 10:31 AM:

While the movie "The Prestige" was playing, I opened the Dolby Digital Processor front panel and I did notice that a letter "F" was being displayed. Also, I did notice some green lights, and it appeared that some were steady, but, I could be wrong. Anyway, I ran the movie once in A-Type and once in Dolby SR. During the last show last night, I turned off the Dolby Digital Reader and ran the print in Dolby SR and increased the Volume setting. Anyway, I left a note in my Log book for my technician to work on it. Hopefully, he will get to it today, since Projector #9's motor quit in the middle of the last show of "The Departed". Well, I will stop there so I don't get off topic. But, if he doesn't, any suggestions would help and I will see about working on it tomorrow. [Smile]