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Topic: Error with 69T

Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-17-2000 05:04 PM

Hello everyone,

A friend of mine performed a Dolby tone level adjustment and a CP500 return with the follow error message: "input level out of range".
I think that Dolby LED or led's transformer has something wrong...
What do you think?
I would like to try if normal level can be set manually and download the EQ to find out what gain is actually set.
Pls note that DOlby is actually working.

Thanks!

Antonio

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Steve Guttag
We forgot the crackers Gromit!!!

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

posted 10-17-2000 05:13 PM

Dolby's auto level in the CP-500 isn't perfect. You are almost always better served to do it manually and look at the Cat. 222SR/A card for the level (if so equipped). If you tried to use the auto level again, it might just work this time, it is flakey at best.

Steve

------------------
"Old projectionists never die, they just changeover!"

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Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-17-2000 05:27 PM

Thanks Steve.

Yes, usually I have to perform Dolby level two times because I note that it set right and left channels to different levels...
To set it manually: should the two Green leds have the SAME intensity? I wonder this because I've noted that Dolby auto level set the lower led brighter than the other one...

Should I have to set them with the same brightness manually??

Bye
Antonio

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John Wilson
Film God

Posts: 5438
From: Sydney, Australia.
Registered: Dec 1999

posted 10-18-2000 05:12 PM

I suggest you never use the auto setting. It's very unreliable. The LCD readout on the front panel on manual will give you (on ours, anyway) the same reading as the green lamps in the rack. So really, you could use either.

I use the lamps in the rack.

A manual adjustment will also give you an idea of where your levels are coming from and going to so you can get some idea of the wear and tear of your soundhead. The auto setting just does it and leaves you guessing.

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Rory Burke
Expert Film Handler

Posts: 181
From: Burbank, CA, USA
Registered: Jun 2000

posted 10-18-2000 05:56 PM

In my experience when auto calibrating the 69t and you get the singal out of range error, there is more with your system than just a simple dolby tone problem. First, you should not rely on the auto cal (manual adjust is always the best route) feature for the following reason. It never quite matches the SR/222 card's display. It might look in perfect alignment on the LCD display put opening and looking at the 222 card/s might reveal something different.
Now as for you signal out of range problem.....simple....you must redo your entire a-chain. Something is physically out of alignment for dolby tone not to align properly even while using the auto-cal feature. Start with some slit illumination test film to ensure that your LEDs(the begining of the "a-chain") are properly centered with the camera and the film. Then use your tone, cross talk, buzz track, and pink noise test loops using an oscilloscpe for the best results(is there another way?) If you rely on just dolby tone to check on the performance of your analog system, you might be misled and mistaken.
Here is another tip........ When adjusting levels for dolby tone on a CP-500 if the gain adjustments are higher than a little more than one third of their total output....recheck your a-chain as you could be overcompensating for a physical alignment problem electrically.

Rory

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Ari Nordström
Master Film Handler

Posts: 283
From: Göteborg, Sweden
Registered: Jan 2000

posted 10-19-2000 04:01 AM

>>Here is another tip........ When adjusting levels for dolby tone on a CP-500 if the gain adjustments are higher than a little more than one third of their total output....recheck your a-chain as you could be overcompensating for a physical alignment problem electrically.<<

Or the the exciter lamp voltage could be too low, or the lamp could be old & slightly blackened.

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