Film-Tech Forum ARCHIVE: Calibrating DD readers without tools

This is topic Calibrating DD readers without tools in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Antonio Marcheselli (Member # 373) on 08-23-2002, 06:20 PM:

Hi everyone.

Let's suppose that you have a DD reader that is not working properly but probably with a good LED.
I know that an oscilloscope is required but is there a way to adjust the reader without it just using, say, meter and DRAS10?

I know that it wouldn't be a good job and that a good tech will spend just few minutes calibrating a DD reader with an oscilloscope.
But I'll appreciate any suggestions from your side on this!!

Bye
Antonio

Posted by Manny Knowles (Member # 1171) on 08-23-2002, 09:08 PM:

Antonio:

Please...get the right tools and do the job completely and correctly the first time. Analog is your backup if your DD equipment is not working.

But you already know all of this.

~Manny.

Posted by Michael Schaffer (Member # 1204) on 08-23-2002, 10:14 PM:

Antonio,
it shouldn`t be too difficult to borrow an oscilloscope, for instance from an electronics repair shop. In my experience, a small batch of free tickets is always very helpful.
Michael

Posted by Steve Guttag (Member # 268) on 08-23-2002, 10:15 PM:

The answer is yes, you can do a credible job with just the puter and DRAS but I'm not telling how cuz as Manny claimed...get the proper tools and do it right. Just because you can, doesn't mean you should.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Randy Stankey (Member # 64) on 08-23-2002, 11:55 PM:

Just shut the player/reader down and run in analog. Call the tech and have him do it or, if you don't have anybody to call, get the tools to do it right.

I have been called to many-a-theatre where people were tinkering with stuff with the best of intentions but they turned a five minute job into an hour's work because of lack of proper tools. Who knows, maybe your tech will tell you top go ahead and work on it. Let me tell you, though... nothing pisses a guy off more than having to undo somebody else's mess before you can do his own job.

Posted by Steve Kraus (Member # 476) on 08-24-2002, 12:25 AM:

DRAS can only tell you what the processor is "seeing" from the film image being scanned into memory and analyzed. When something isn't right it may not always be apparent WHY it's not right. You may be able to zero on on some adjustments between the software, what you see on the decoder displays, and trial and error but it really helps a great deal to see the actual signal on a scope. Since a scope is a relatively common piece of test gear it doesn't make much sense to fool around without it, like you might be inclined to if some sort of exotic or proprietary instrument was needed.

Posted by Antonio Marcheselli (Member # 373) on 08-24-2002, 04:08 AM:

Thanks guys,

I hope that my manager will have a tech on it because Proj 2 has big problems with DD. Since the theater has no long life, I hope so! This is why I asked for no-tools adjusting!

Bye
Antonio

Posted by Antonio Marcheselli (Member # 373) on 08-26-2002, 06:42 PM:

Ok, let's suppose I have an oscilloscope.

Is there a document that explain exactly how to calibrate a DD reader? I mean, on the Dolby manual there is the procedure for the Dolby cat 700 reader. I have a Cinemeccanica reader (red LED).
Where can I found detailed instruction? Can anyone post me some help? I saw a tech calibrate one reader and I understood what has to do. But I wonder if there is some wrote "official" instructions.

Thanks in advance for your help.

Antonio

Posted by Mike Babb (Member # 1379) on 08-26-2002, 11:12 PM:

It's probably available in other places but there's definitely a section in the CP500 manual download on this site that tells how to align it.

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Mike
Drive-In Records
www.driveinrecords.com

Posted by Antonio Marcheselli (Member # 373) on 08-27-2002, 03:59 AM:

Mike,

Thanks for your reply.

I've read the CP500/650 alignment procedure. I know what has to do but I don't know exactly how the Cinemeccanica's reader works! For example I downloaded the CE reader's instructions and they are very clear. For example they explain hot to move the led forward/backward to achieve the maximum brightness. I do not know how to do the same (mechanical) on the cinemeccanica's one! I can try, but I wonder if there is something wrote like CE.

Bye
Antonio