Film-Tech Forum ARCHIVE: Issue with Smart Mod V

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Posted by Rich Ferrando (Member # 2056) on 12-08-2003, 01:21 AM:

Hi, kids- I'm new to the forum (and still somewhat green as far as the booth is concerned, but I like to think I'm learning fairly quickly) and I have a bit of a technical issue with our sound processor that I'd like to try to resolve.

The booth in our main house is equipped with the following lovelies:
USL's BACP DSTR-20 Dolby penthouse reader
Component Engineering FM-37 cue detector
Component Engineering basement reader for Century
Component Engineering TA-10 Automation (I believe - will double-check that)
Dolby DA-20 processor
Smart Mod V processor

The digital sound was installed about 6 months ago. However, since the installation, we've been getting an issue with the processor automation:

At the end of a film, everything goes the way it should - the end cue brings the house lights up to full, closes the douser, and switches the Smart processor to "Music." However, as soon as the start of the tail runs through the projector, the Smart processor switches to "Stereo," and thus all that lovely audio garbage at the end of the reel is heard, loudly, in the house. It remains on Stereo after the motor shuts off as well. This issue only occurs with the processor in Digital mode - in SR mode, everything works beautifully.

Also of note - the Smart processor starts up in Stereo mode, not in Music mode (the manual states that the processor should default to Music on startup.)

Any ideas on what might be wrong, and how to fix it?

Posted by Manny Knowles (Member # 1171) on 12-08-2003, 02:54 AM:

I have to admit I've never checked out a MOD V or the BACP reader but, still, it is possible that your SRD reader is re-engaging the processor which then defaults to analog when it loses data.

If that is indeed the case then you might try moving your "kill" cue closer to the tail. (I usually kill the show in the middle of the blue MPAA band.) If that doesn't work for you then you have two options:

(1) Remove those tails and use a drag-strip in place of it; or
(2) Configure your system so that it functions properly. [Wink]

What's a drag-strip? It's stock film -- blank & silent -- perfect for attaching to the tail of your shows so that you don't drag the actual film on the floor after tail-out.

Posted by Oscar Neundorfer (Member # 458) on 12-08-2003, 06:49 AM:

Hi Rick,

Welcome to the forum!

The MOD V should start up in music unless something else is telling it to go to stereo. If anything external (like an automation) is grounding one of the format lines, then the music default will be overriden. Another possibility is that for some reason, this MOD V has been modified to start in a stereo format instead of music. Check by removing all automation connections and DA-20 connections from the MOD V. Now power up the MOD V and see if it comes up in music format. If it comes up properly in music with these connections removed, then something external is overriding the default start-up format. If it still comes up in a stereo format with these connections removed, then something is wrong with the MOD V (or it has been modified to do so).

You can call SMART at 1-800-457-6278 and ask for service. We will be happy to figure out what is wrong and send you replacement parts.

As to the other problem of reverting to stereo after it has switched to music, my guess is that something external is causing that. Either the automation or the DA-20 is (for some reason) grounding the stereo format line after it has previously switched to music. Make sure the automation is programmed correctly and that no extraneous cues are on the film or that the cues are in the wrong places. (see Manny's post)

Posted by Rick Long Jr (Member # 541) on 12-08-2003, 10:11 AM:

The DA-20 is smart enough to know it shouldn't switch to analog after the processor has gone to non-sync. But if it doesn't know the processor has gone to non-sync, it will switch to stereo and you'll hear the tail run through. I'd bet the auto interface between the Smart and the DA-20 needs to be checked. Chances are the non-sync command isn't making it to the DA-20. What position is the CP selector switch on the DA-20 in?

Posted by Marc Jones (Member # 29) on 12-08-2003, 12:12 PM:

just curious could the position of the cue tape cause this , if it causes the dolby DA 20 tho fail and revert back to stereo.

If this was the case couldn't you remove the cue tape and manually select nonsync when needed and see it still happens.

Posted by Rich Ferrando (Member # 2056) on 12-09-2003, 10:40 AM:

Thanks a lot, guys! I really appreciate it!

I'll take a look-see tomorrow and keep you posted.

Posted by Michael Schaffer (Member # 1204) on 12-09-2003, 08:56 PM:

How does the Auto Digital feature influence the automation with a MOD V? What processor type do you configure the DA-20 for with the MOD V?

Posted by Gordon McLeod (Member # 33) on 12-09-2003, 09:14 PM:

I set the DA20 for a CP65

Posted by Rich Ferrando (Member # 2056) on 12-10-2003, 05:30 PM:

Okay, here we go -

I did a quick check of the MOD V and DA-20 today. First thing I noticed was that the DA-20 was set for a CP55. So, I first tried adjusting to the CP65 setting as Gordon suggested, after which the MOD V to switch to SR, and the DA-20 no longer aknowledged a digital signal. Thus, I switched it back to the CP55 setting so that the DA-20 would pump digital again.

I checked the connections on the rear panels of both components. Under the Automation for the MOD V, the only connections are to the Ground, SR, and Music.

The DA-20 and the MOD V are connected via a DB25 cable, which is "split." Essentially, the single DB25 Digital Input connection on the MOD V has two cables running from it - the first goes to the Audio Output DB25 connection on the DA-20, the second to the CP Sense DB25 Input on the DA-20.

When the first show ended I was going to attempt to unhook the DA-20 and Automation connections to see if the MOD V would start-up in Music mode, but around that time a pressing issue occurred (lamphouse randomly shut down during a film) that kept me occupied the rest of the day. I'll test that out tomorrow.

Anywho, does this configuration sound kosher, or is this just completely wonky?

Posted by Gordon McLeod (Member # 33) on 12-10-2003, 07:19 PM:

very odd I always used the cp65 setting
when all the cables were removed did the mod v boot up correctly to music
If so it is possible that the film runout on the TA10 is wired to hold the modv in sva by mistake

Posted by Rick Long Jr (Member # 541) on 12-10-2003, 08:22 PM:

I believe it is as I suspected. The non-sync trigger is not making it to the DA-20.
Looking at the pinout for the DB-25 on the Mod-5 provides auto trigger pins for ground, digital, and SR(or A), but NOT for non-sync. With the DA-20 in CP 55 mode, the sense/control connector triggers pin 8 for digital, pin 2 for SR, and looks at pin 7 for non-sync. You should be able to simply connect a wire from the music terminal on the Mod-5 auto interface to pin 7 on the Sense/control D-sub. THere may be extra conductors in the existing cable. Probably something you may want to get the tech back to fix, unless you have the necessary experience (and will get paid for it [thumbsup]

)

Posted by Rich Ferrando (Member # 2056) on 12-11-2003, 12:03 AM:

The head engineer for the company will be out in a few weeks to install digital into our other two houses, so before I go ripping things apart, I'll consult with him first, because I simply don't have the necessary know-how yet. 'Tis better to be safe than stupid in this case. [Wink]

Thanks for the help!

Posted by Oscar Neundorfer (Member # 458) on 12-11-2003, 07:53 AM:

Rick Long is correct in his assessment of the connections between the MOD V (DIGITAL INPUT DB25 Connector) and the DA20 Control connector. Only digital and SR pins are provided, but NOT non-sync.

If the interface cable is one supplied by SMART, then the processor selection switch on the DA20 must be set to the CP55 position.

It is easy enough to provide an extra wire between the MOD V AUTOMATION connector MUSIC terminal and pin 7 of the DA20 CONTROL DB25 connector. This may be all it takes to solve the problem.

However, the lack of this non-sync connection to the DA20 has not proven to be a problem over the years. Or if it has, then it has NOT been reported to me. (I used to think that no news is good news. I have changed my opinion on this to think that no news is really trouble brewing!)

Please correct me if I am wrong (since I have no real booth experience), but it seems that the DA20 should have already reverted to SR by the time the automation has sensed the end of show cue. At that point the automation should switch the MOD V to MUSIC format. Since the DA20 has already reverted, then there should be no problem of going back to SR format on the MOD V. It would seem that moving the end of show cue a bit would allow the DA20 to revert before the automation switches to music format. The correct timing and sequence of events is essential.

To digress a bit, this scenario was always a problem with DTS because it would take 3 to 4 seconds after the DTS lost timecode to revert back to SR. So the reversion would occur AFTER the automation had switched the processor back to non-sync, and then the processor would be switched back to SR. I always thought that the DTS should KNOW the last timecode reading on any given print and should NEVER revert to SR after the last timecode had been read. I guess this was just too simple a solution.

Posted by Michael Schaffer (Member # 1204) on 12-11-2003, 11:52 AM:

[Confused]

If correctly configured, DTS pulses the main processor to non-sync by itself. Sometimes there were problems, for instance with the CP500, because most installations use SK7 for non-sync while the automation interface board for DTS typically was jumpered to SK8. So the automation would switch the CP500 to SK7, then DTS would switch it to SK8. But that problem could easily be solved by moving the jumper on the interface board to the SK7 position.

Posted by Oscar Neundorfer (Member # 458) on 12-11-2003, 12:06 PM:

Michael,

If I am correct,the original DTS-6 would only select digital or optical stereo. There was, as far as I know, no provision to select non-sync (except MAYBE when used with a CP-200, but I am not sure).

The DTS-6D could select any format, but my understanding was that this would happen ONLY if the discs had the necessary information about which format to select. I may not have this right at all, so please correct me if I am wrong.

Posted by Daryl C. W. O'Shea (Member # 1303) on 12-11-2003, 12:08 PM:

If I remember correctly you've got it right Oscar. A software update a ways back now fixed the 6D's problem with ending the show nicely.

Posted by Gordon McLeod (Member # 33) on 12-12-2003, 09:46 AM:

the unawnsered question still also remains why does the processor wake up in a film format not nonsync

Posted by Rich Ferrando (Member # 2056) on 12-13-2003, 12:25 AM:

We put a new film into the house with the MOD V today, and it does even more "jumping" between formats with this one. I'm going to try moving the end cue back a few more feet tomorrow, and also try pulling the automation and restarting the MOD V to see what mode it starts in.

But, essentially, this is what happens now: end cue goes through, MOD V switches to Music for approx. 5 seconds. Tail begins running through, MOD V switches to stereo for a split second, then to Digital for aprrox. 1 second, then back to Stereo just as the tail finishes running through, and remains on Stereo when the projector shuts down.

It took me two shows to figure out exactly what it was doing, since the switching happened so quickly. Semms to me that the cue placement must have something to do with it, since the details of the issue have changed between the last film and this one.

Posted by Daryl C. W. O'Shea (Member # 1303) on 12-13-2003, 08:33 AM:

Not all tails have digital on them, some have digital all over them, and others have bits of digital here and there. That would explain why it has changed with the new print.

Like Rick said, you've got to be missing the non-sync line to the DA-20. Fix that and your tail-out problem goes away.

Posted by Rich Ferrando (Member # 2056) on 12-13-2003, 04:50 PM:

Yup - I think Rick's definetly right on this. I pulled the connection from the DA-20 today, and, indeed, the MOD V started up in Music, just like it's supposed to. I'll have a talk with the company engineer when he comes out, and maybe he can string an extra line from the music auto-interface to Pin-7 on the CP control on the DA-20.

Thanks a lot for all the help, guys! I really appreciate it!