Film-Tech Forum ARCHIVE: Nearing the end of my rope- Dolby SRD troubles, HELP!

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Posted by Aaron Sisemore (Member # 145) on 11-06-2003, 06:42 PM:

OK I have been getting the calls since yesterday on the following problems:

Location #1: Dolby CP500; Simplex 5-star with Kelmar SRD/analog LED basement reader- From reports I have been given, prints have been running just fine until yesterday, when 'Matrix Revolutions' opened. The complaint is that the film is dropping out of digital constantly. A new print was obtained, and as of this writing they are a couple reels into the first show and the trailers prior to the attachment played fine, but as soon as the attachment hit, the error rates have been 6-F-7-F with many reversions to analog. Reports I have been given also say that the movie that was in that auditorium previous to Matrix ('Mystic River') played fine in SRD.

Location #2: DA20, Cat 700, CP65; Century projector- I was at this theatre on Tuesday for regularly scheduled maintenance and received reports that the digital problems had gone away in recent weeks (more on this later, it may or not be relevant). The ONLY thing I did to the DA20 was replace the front cover (which was off for troubleshooting purposes, per instructions from Dolby). To my knowledge, the film playing Tuesday (Brother Bear) played flawlessly. Come Wednesday, first show of 'Matrix' plays and voila! massive amounts of digital reversions and error rates in the 5-F-6-F-7-F ranges... BUT WAIT....THERE'S MORE: This same theatre playing the same print of Matrix ran from what was reported to me by the staff for the second show without EVER reverting... Then the late show played and the reversion hell was back- to include a few times where the film dropped from SRD to SILENCE!!!!!!! [Mad]

This location also got a new print of 'Matrix' and as of this writing it is playing OK but the thing hasnt played all the way thru yet.

This location has been having sporadic problems with the SRD in both of the two SRD houses they have (the other two are SDDS and DTS) and they have had prints go into reversion hell (one of which [Bruce Almighty] I heard the revisions myself)- Lonny Jennings came down and hooked up the laptop and scope and we ran the SAME PRINT OF 'BRUCE ALMIGHTY' and there were ABSOLUTELY ZERO REVERSIONS, with error rates between 1 and 4!!! From what I can remember the print played just fine... Until this EXACT SAME scenario happened again several weeks later with 'Hulk'...

I am beginning to tire of the bitching from both upper management and theatre managers that assume that I have the 'magic bullet' to make things work... My supply (and Dolby's in the latter case) of ideas and fixes is running dry and I am beginning to believe that an exorcism is in order on both these places, especially the latter one!

SOMEBODY PLEEEEEEASE HELP!!!!!!

-Aaron

Posted by Gordon McLeod (Member # 33) on 11-06-2003, 06:49 PM:

Wild shot is there a possible threading problem IE tension on the damper in the reader
If it is incorrect it would cause jitter that would drive the error ate up to silly revisions

Posted by Daryl C. W. O'Shea (Member # 1303) on 11-06-2003, 06:50 PM:

The sypmtoms would point me towards dying LEDs. I've had similar things happen with a pair of weak LEDs. This'd be especially likely if you'd installed or adjusted both LEDs around the same time.

Oddly enough, I had the same experience you describe with a print of Bruce Almighty.

Posted by Aaron Sisemore (Member # 145) on 11-06-2003, 10:27 PM:

quote:
The sypmtoms would point me towards dying LEDs. I've had similar things happen with a pair of weak LEDs. This'd be especially likely if you'd installed or adjusted both LEDs around the same time.

The Kelmar reader had an LED change this spring (when 'Phone Booth' was out), I would assume they are still in good shape.

The other location has a Cat 700 reader, no LEDs- and yes it had a brand new bulb put in it just prior to the Bruce Almighty incident.

Update: Both locations with the new prints STILL revert with error levels in the 7-F range. I did what I could at location #1 to get it back, but couldn't get it to improve.

AAAAGGGGHHHH!!! [Mad]

-Aaron

Posted by Steve Guttag (Member # 268) on 11-06-2003, 10:51 PM:

Aaron,

Two things...have you put your scope on the DA-20s? That is what is the video level for the various readers? You really want to shoot for 4V p-p on the Whiter-than-white burst (when it is reading the perforation).

On the 5-star...press down on the pinch roller just a bit and see if that steadies it out. One of two things happen with the Simplex (and particularly the 5-star) soundheads...The pinch roller MUST BE CLEAN. Scum on the roller will make it start to bounce (not really perceivable to the eye). When this happens, you vertical jitter on the Dolby Digital track will be too rapid and you will get the higher errors and Fs.

The other thing on the 5-Star is if the damper roller has too much spring tension on it, it will pull up on the pinch roller and defeat part of what it is doing...make sure that isn't happening.

Steve

Posted by Manny Knowles (Member # 1171) on 11-06-2003, 11:10 PM:

Conveniently, SRD jitter manifests itself in the upper-right portion of the scope traces. If it is jittering, then you have jitter.

Posted by Bill Gabel (Member # 1105) on 11-07-2003, 09:34 AM:

We had a small problem with one machine here. That on two prints that ran, that machine would revert to SR for a few seconds on the startup and revert a few times during the reel. (No it was not a bad reel) On both prints I had sound editors present. And both prints had been screened at other locations , fine. I have Kinoton basement readers on my Magna-Tech PR-135 machines. We had Dolby NYC here yesterday to work on it. They found the tension was off a bit, so the flywheel was not getting up to speed on that machine. So it would drive the error rate up and revert. It ran steady on all shows yesterday. I ran 21 reels and it ran fine with 3's & 4's on the CP500.

Posted by Rick Long Jr (Member # 541) on 11-07-2003, 11:04 PM:

Something you may want to try is simply reseating all of the cards. 90% of the time, this does the trick with CP-500's, but it could be a faulty card as well. If you can, try swapping the digital sub-system with another screen and see if the problem moves. If so, then do it one card at a time to isolate the problem. This is, of course, if you get lucky, and the problem appears while you're there.I've found the CP-500's can be flaky. The CP-650 is MUCH better with regard to how the digital performs.