Film-Tech Forum ARCHIVE: Need Dolby DA20 Help

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Posted by Thomas West (Member # 7810) on 08-11-2013, 05:59 PM:

I'm new here, I run projection in an old Art Deco theatre with two auditoriums (the smaller one is in the building next door). I'm having a sound problem in the smaller room. It has a Dolby DA20 with a CP200 in the rack. This room used to have digital surround, but last summer the DA20 was moved to the main theatre and a "new" one was installed in the small room. The problem is that since the change was made, there is only analog sound coming from the speakers behind the screen. When the movie is playing, the Dolby reader is on and the DA20 shows a number in it's window. Under CP Status, neither the Digital nor Analog LEDs are lit. Format number 10 is selected on the CP200. The manual says that if neither the digital nor analog LEDs are lit on the DA20, the wrong format number is selected on the CP200. Can anyone help me with this?

Posted by Paul H. Rayton (Member # 1817) on 08-11-2013, 07:14 PM:

First question: is the DA20 set to communicate with a CP-200? If it was brought in from a different screen, and was not working into a CP-200, it might be set for some other processor (CP-65 or others of its ilk). There is a rotating switch behind the DA20 cover on which you select the destination processor type. You might confirm that first.

Posted by Thomas West (Member # 7810) on 08-13-2013, 08:02 PM:

Paul -
I can confirm that the Cinema Processor Type switch on the DA20 is set to 3, which according to the manual equals CP200.

Thanks,
- Tom

Posted by Thomas West (Member # 7810) on 08-18-2013, 02:17 PM:

If no one here can help me with this issue, can anyone please direct me to a site that might be able to help?

Posted by Sam D. Chavez (Member # 1841) on 08-18-2013, 03:47 PM:

Thomas,

First things first.

You state a number is displayed on the DA20. What is the number, 1, 2, 5, F?

On the left most cards of the DA20, there are 670, 671s, 673 and 675 cards among others. Is there any activity on the 671 cards when running film?

On the 611 card on the right, is there audio signal presence on the little green LEDs?

If no activity on the 671's, just a wild guess but when the current DA20 was installed if the video cable was plugged in with the reader and/or DA20 was powered up, the CCD in the reader is blown or the DA20 front end is blown up. The best visual indication with no test equipment would be lack of activity on the 671 cards and an F as in failed in the DA20 display. If you are getting a good steady number the audio is being processed but not getting out of the DA20 for some reason.

There should be logic lines connected between DA20 and 200. Also audio out, both cables are DB25. Make sure the audio out and logic line are not interchanged.

That's a start. Write back when you have more info.