Film-Tech Forum ARCHIVE: Dolby Jumping From 7 to Fail

This is topic Dolby Jumping From 7 to Fail in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jason Setzer (Member # 3949) on 09-20-2006, 10:58 AM:

Our biggest auditorium is equipped with SDDS/Dolby digital/SR. The last 2 movies we played in that theatre did not have a SDDS soundtrack, so it has been running in DD.The problem is that the the reader is constantly going from 7 to fail. The flyweel inside the Digital reader is making a funny rubbing style sound [Eek!]

. Can anyone help.

Posted by Demetris Thoupis (Member # 833) on 09-20-2006, 11:02 AM:

First of all welcome to the club!
The first thing you have to do is call your service technician to come and check the reader because it sound like it is not allinged properly or has become missalinged for some reason. You fail to mention the model of the reader,projector and your processor which can help lads here to help you out in finding the problem.
Best Regards
D

Posted by Jason Setzer (Member # 3949) on 09-20-2006, 11:21 AM:

Equipment:

Projector: Century

Sound: SDDS 3000
DOLBY DA20
DOLBY DIGITAL READER 701

WE ALREADY HAD THE ALIGNMENT CHECKED AND IT WAS CORRECT. I THINK THE ISSUES LIES WITHIN THE SOUND DRUM/FLYWEEL. THIS ISSUE JUST OCCURED WITHIN THE LAST 2 WEEKS AND THIS PARTICULAR THEATRE HAS ALREADY RAN STRONG IN DOLBY DIGITAL.

Posted by Frank Dubrois (Member # 3042) on 09-20-2006, 01:01 PM:

If you arent comfortable removing the back cover (assuming its a 701 penthouse reader) then you'll have to call your tech again. Sometimes just by looking at it, the problem becomes obvious. If your not comfortable looking into it, then hang around when your tech shows up. Watch what he does.

By the way, have you checked out the manual? If you dont have one, the manual for this unit is here on the site.

Posted by Brad Miller (Member # 2) on 09-20-2006, 02:27 PM:

The obvious question...has ANYTHING changed in the last few weeks? Has ANY service been done or anything at all?

Also have you tried a different print?

Posted by Demetris Thoupis (Member # 833) on 09-20-2006, 02:29 PM:

I once had an issue at a cinema with a faulty CAT 670 card on the DA20 unit. Everything checked out fine on the allingment but the card had a problem and could not decode. If I am not mistaken is the video aquisition card. For starters you can try swapping it with another working DA20 unit (that card) if you have a multi cinema venue.
Best regards

D

Posted by Jason Setzer (Member # 3949) on 09-20-2006, 03:15 PM:

We have tried 3 movies in here that have strong readings in other theatres . They all have the same response. I know how to align the Dolby LED so I know that isnt the problem.

As far as the DA20 unit the rest of our 10 screens and IMAX are equipped with the 5000 series.

We do most of the servicing in house as we only have 25 screens through our 4 theatres (unless it is outside our knowledge base).

As far as the manual goes yes we have the manual and it does come in quite handy.

Brad there has been no changes at all the in last 3 weeks except that I replaced the SR led, realigned the SR and did an A-Chain alignment(BACP). But I don't think that would have anything to do with the Digital.

Posted by Demetris Thoupis (Member # 833) on 09-20-2006, 03:26 PM:

You mean you have CP500 in the other houses? If so the Cat 670 is the same. Try swapping it and see how it goes. anothe suggestion would be to exchange the reader from another screen the CAT 701 and see what happens. Its a matter of trial and error to see the real problem. I don't know any 5000 series [Confused]

Posted by Richard Fowler (Member # 893) on 09-21-2006, 03:51 PM:

"Rubbing sound" could also be bad bearings on the CAT 701 sound drum. The drum shaft has a spring behind the flywheel to take out side play, which if missing or not allowed to keep the shaft in "tension", will give you playback problems...had this problem a few weeks ago at a premiere.

Posted by Jason Setzer (Member # 3949) on 09-21-2006, 05:34 PM:

Flyweel was loosing tension, which was causing the reader to read strong then fail. Thanks Guys!