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» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » CP-65/DA20 not falling back to analogue automatically (Page 1)

 
This topic comprises 2 pages: 1  2   
Author Topic: CP-65/DA20 not falling back to analogue automatically
Andy Patterson
Film Handler

Posts: 4
From: Soho, London, UK
Registered: Jan 2012

- posted 09-14-2012 12:50 PM      Profile for Andy Patterson   Email Andy Patterson   Send New Private Message       Edit/Delete Post 
Hi,

We recently had our two FP20s replaced with a digital projector and a single Century film projector. The wiring from the old Proj. 1 was simply reconnected to the Century, only since the change the Dolby set up will no longer automatically drop back to analogue if the digital sound is interrupted, as it used to.

All of the channels on the CP65 work as usual when selected manually. However if it's on Digital 10 and I block the light from the digital sound head the sound just cuts, and the green 'Digital' LED on the DA20 remains on (where it used to change to the yellow 'Analogue' LED).

I've attached an image as there are a few seemingly home-grown adaptations, the righter-most of which used to turn on or off the function I am enquiring about.

I have checked the multi-pin connector on the back of the DA20 and it is seated correctly, nothing was touched on the sound rack during the install.

Any ideas?

Thanks,

Andy

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

- posted 09-14-2012 02:06 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Is the flat control cable plugged in Da20 to CP65?

If so, is the rotary switch on the front right of the DA-20 in the correct position?

My memory of that combination is old, but I think the light on the da20 should change upon reversion. If not, something is wrong (switch) or broken in the DA20. louis

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

- posted 09-14-2012 03:28 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
If you previously had two projectors you must have had motor sense relays and a changeover device that is no longer needed.

When going down to one projector you need to eliminate projector 2 relay and can jumper out the DA20 db9 pins so the projector is hardwired to proj. one.

This is where I would look first.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

- posted 09-14-2012 04:02 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Good catch, Sam.

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 09-14-2012 05:41 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
^^^ What Sam said.

Jump pins 1 and 5 of the DB 9 motor start connector together. [beer]

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

- posted 09-14-2012 08:16 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
Why would this matter? The projector 2 relay will (should) never close as long as there is no projector 2, and the projector 1 relay will (should) only close when projector 1 is running, which should work fine. As long as everything is wired correctly, there should be no problem with running one projector only. It's done all the time in booths that have two projectors and a platter.

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 09-14-2012 09:37 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
Scott, it matters because as stated in the DA-20 manual, If a motor start signal is not applied the DA 20 will never revert to analog because without a motor running it is presumed that an analog signal is not available. Doesn't matter if it is a single or two projector setup.

On two projector setups for changeovers the motor start is also used to start the DA-20 in looking for valid Dolby Digital Data prior to the changeover command.

Jumping the terminal I mentioned forces a "Motor Start 1" at all times. The DA 20, CP500 and some CP 650's ship with a connector and that jumper from the factory.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

- posted 09-15-2012 02:10 AM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
quote: Tony Bandiera Jr
Scott, it matters because as stated in the DA-20 manual, If a motor start signal is not applied the DA 20 will never revert to analog because without a motor running it is presumed that an analog signal is not available. Doesn't matter if it is a single or two projector setup.
Right, but as long as the M/S relay is still properly connected to projector 1, this condition will still be satisfied.

Or is the assumption that the installer didn't do this?

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

- posted 09-15-2012 06:47 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
The digital installers either dont know or dont care.
"Butcher jobs" on the 35mm. Most of the calls I get these days are vandalism on 35 by the "fast install,one foot in the car" digital installers.

btw: So far, I have NEVER seen a CP750 B-chain performed. They claim it isn't needed. Louis

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

- posted 09-15-2012 08:55 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Wow Louis! I want to FRAME that post! [thumbsup]

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

- posted 09-15-2012 10:23 AM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
quote: Louis Bornwasser
btw: So far, I have NEVER seen a CP750 B-chain performed. They claim it isn't needed. Louis
And I thought that an EQ done in 15 minutes was the worst ever.
How sad.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

- posted 09-15-2012 09:00 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
Even if the EQ stays flat, they still need to set levels for everything, at which point, the installer might as well just do the EQ, anyway, since necessary the equipment is already set up. What is the D-cinema equivalent of cat. 151, anyway?

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 09-15-2012 09:23 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
quote: Scott Norwood
What is the D-cinema equivalent of cat. 151, anyway?
Ummmmmmm, you do know that CAT 151 is/was a test film designed for subjective testing of center/surround balance, right? You don't use it to set B-chain levels with. In fact NO test film is or was intended for use to set B-Chain levels or EQ..that is what the CAT 85c card and the current processor's built-in pink noise generators are for. [thumbsup]

To answer your first part of your post, I don't think ANY technician on here has ever encountered a room where the EQ would stay flat, with the extremely rare exception of a room feeding the output of a CP-750 into the analog inputs of another processor. In fact, the few installs I am familiar with that have both a film processor AND a CP-750, they do the reverse and feed the output of the film processor into the analog inputs of the CP750, as the CP 750's B-Chain facilities are better than most older processors anyways. In those cases the EQ's of the film processor are indeed set flat.

quote:
btw: So far, I have NEVER seen a CP750 B-chain performed. They claim it isn't needed. Louis
Whoever "they" are need to be outed on this forum and have their hands and legs broken, then subjected to endless hours of Justin Beiber music played in headphones at 110db (with no EQ) until their ears bleed. [Mad]

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

- posted 09-15-2012 09:45 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
quote: Tony Bandiera Jr
Ummmmmmm, you do know that CAT 151 is/was a test film designed for subjective testing of center/surround balance, right?
Right. But it's still part of the process, I assume as a sort of sanity check for surround levels. What is the D-cinema equivalent of this?

And I'm not suggesting that leaving the EQ flat is a good thing...just that if an installer is dumb enough to do it, he still needs to set the levels correctly for each channel.

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 09-15-2012 09:51 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
Well I would disagree with you on the sanity check part as if you do a proper A and B chain CAT 151 is a waste of time. [thumbsup]

There is no D-cinema equivalent to 151, and what value would checking only the center and surround have anyways? (Remember that 151 was mainly designed to make sure the CAT150 matrix was working properly.) You need to check ALL of the channels, and Dolby Servers (others most likely do as well) come pre-loaded with channel ID and "check" clips. You use them to make sure all the channels are speaking from the right places and that subjectively the overall tonal balance is the same. But they are NOT used to set levels or EQ.

IMHO, the content for channel and sound checks on the server are the equivalents of the 1011 Channel ID test film, and the output of the server itself is the D-Cinema version of the A chain. In film, level and EQ of the A chain was made adjustable due to the variety of optical reading methods and to account for aging of illumination and/or optical focus drifts. Something D-Cinema doesn't have to deal with.

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