I'll be the first one to say that I am a projectionist, not a projector technician. However, I do try to deal with problems myself before freaking out and calling a tech. (After all, why bother them for something minor that I can handle on my own?) I'm fairly sure that I will have to call a tech for this one, I just want to see if there is anything else I could have checked and/or done before making that call. My SRD is not working.
The Digital Soundhead is a Cat. No. 700, and the SRD digital film sound processor is a Model DA20.
I'm not sure if the problem is with the reader or with the processor. But on the soundrack where a number (or sometimes an 'F') is displayed while a film is running in SRD, instead there is simply a '-'. Short, flat line.
I've already checked for blown fuses and loose wiring. All was fine.
The bulb in the soundhead is working fine, not burnt out.
All appropriate lenses are clean, and everything ought to be properly aligned (being at least a good 5.5 feet off the floor, directly over a beastly Century JJ2STA projector head, keeps things well out of harm's way as far as getting 'bumped' and misaligned!)

Mind you, I have no test loops, or hardly anything else in the way of equipment for running tests. And too, my knowledge of electronics is minimal.

I appreciate any advice that will get tossed this way.

~Gracia

In these days where everything has an SRD track on it perhaps this one does not.

Is this the same on all prints and trailers or just one title?

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The Dolby Digital, SDDS and analog/DTS time code tracks all have separate light sources on the printer, so one can fail even on "quad" format prints.

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To all you other wise-guys, yes, the prints that I have run on the machine do have the SRD track! I know to look for Dolby's 'double d' logo in the gray shaded areas, and I can see it just fine without a magnifying glass!
Highlander: Endgame and The Way Of The Gun have both run on that machine. And Endgame was running in digital for a few days before the digital went the way of the dodo!
I may be a lot of things, but I am not silly enough to run a print without an SRD track on my machine with the SRD reader and expect to get digital sound!

~Gracia

If you have tried another print which you know to be OK without success, then all I can think of is the following:

1. Exciter bulb on the way out. I know you said it's not blown but the light from halogen lamps gradually deteriorates during their lifetime. Just as you have to keep resetting the gain on an SR analogue (incandescent) exciter over the course of its lifetime to compensate for the reduction in light output, the same problem with digital will show itself as a gradually increasing error rate. Has the error rate gradually been getting worse on that reader over the last few days or weeks? If so try changing the lamp. If it's been in for over a year, then personally I'd change it anyway.

2. Optics (exciter and/or CCD) dirty. I know you said they were clean but there's nothing to lose by trying the following. Take a compressed air spray, pointing the jet laterally across the exciter lens and the CCD (metal tube next to the scanning drum), and give a brief squirt. Do not point the nozzle straight at it as the force of the air pressure could cause damage.

At this point, I'd give up and call an engineer, because unless I'm being really stupid and missing something, the only other possibilities are:

3. Optics and/or CCD have become misaligned. Have you had a platter wrap recently, or has the Cat 700 been knocked for any reason? If so this could have happened. You need to call an engineer to fix this - there's nothing you can do about it yourself.

4. Internal fault within the DA20 - ditto.

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