I hooked it up to DRAS and checked it out. Turns out the reader was a bit out of alignment but the print was also marginal quality.

Once I got it going good I left the thing hooked up when the movie started.

The test film got a score of 65-70 on the focus reading. (The best this machine has ever gotten.)
When the trailers started the focus went down to 50-60. Still not bad for this machine. The error reading was between 4 and 5.
When the featre started the focus went down to 40-45. The error reading went up to 5 and 6. When a splice would go through it would be on the verge of dropping out.

Judging by that I'd say that the print was marginal quality. That's what I put in my report anyway. I guess what you just said validates my report. (Unless there's something ELSE. )
 

The first thing I always do when I get a report of problems with a Dolby unit is check the LED levels. Since you don't have LEDs in yours that's not the case. BUT the lamps in yours could be getting old. When's the last time they were checked or replaced? That's a quick and easy way to find out what the problem is. If you replace the lamp and there's no change, you haven't done any harm. You have even done your tech a favor by eliminating an easy problem.

Another thing you could check is the cleanliness of your optics. You are probably pretty scrupulous about this but it couln't hurt to get a Q-Tip and give it a whirl.
 

What I've been doing is taking a piece of brand new film and running it through several Dolby Readers and finding the average readings I get. Then I take a fine-tip Sharpie® marker and write those numbers on the strip of film. When I do an alignment I can look at the numbers I get and know whether I've gotten it as good as it can be.

That piece of film will be used ONLY for Dolby alignments until I think it's getting too worn out, at which time I'll use it for something else and get a fresh piece for Dolby.

Sometimes I think I ought to use the Pink Noise film. It might have something to do with the background color of the film. (Red light & green film, y'know.) I just think Dolby ought to make a special test film on clear base just for Dolby reader alignment.
 

When I align using the Dolby tone and p/n loops, the errors generally sit between 3-5 on regular prints.

I'm certainly going to give it a try. I have one Dolby System that just doesn't seem to want to behave itself. (Christie basement & DA-20 )
I do the base alignment with the scope, moving the "cell" in and out to get the highest output. There is just this one spot where it'll read right. If I move it just a fraction of a milimeter either way I lose it. Instead of getting a nice smooth trace with little ripples across the top I get these huge "mountain peaks". When I do get a good trace it'll work but the magnification reading on DRAS reads 108%. It seems to me that the "zone" should be bigger, allowing me to adjust the magnification to between 99% and 101%. Once I get that part set up I can get the rest of the alignments right but I never get above 70 on the focus. Other units I work on get readings that are consistently in the high 80's.

I have put on the O-ring sound drum, new bearings and the new lens. I fiddled around with flanged rollers on both top and bottom lateral guides. There is a new LED and a new regulator. I have changed all the belts and cleaned all the crud off the grears and pulleys. The best readings I can get are in the 4-6 range. Some of my other machines are running at 4 and below. This one's just got me totally peeved off.

At this point I'm willing to try just about anything.
 

Now I didn't think about the fan or the wattage of the lamp. It IS a large lamp (6K). What about the lamp heating the film? I didn't consider that. Next time I go take a crack at it I'll be sure to disconnect that fan. (Is it really all that necessary, even on a big lamp like that?)

The problem is when I do that first, basic alignment. You move the "cell" around till you get the best picture on the scope. I can get a good light output but when I do it's at 108% mag. If I try to move the cell closer to get a smaller picture I lose the light. The trace on the scope just collapses into nothingness.

Now here's the kicker! I was just at that theatre this evening. Prints are all moved around and there's a print of Fast & Furious in there now. The readout on the DA-20 is showing an average of 3 to 4 with occasional spikes as far as 2 and 5.

At this point I'm just going to leave well enough alone. I know I'll be just falling asleep one night and it'll hit me... AHA!!!
 

DRAS is only a "readout" program. It will show you how the system is performing but there is no way to make adjustments with it. Those adjustments need to be done by tweeking the reader itself. Furthermore I wouldn't dare make adjustments to a reader with DRAS alone. I have been shown that there are times when the software will say one thing and the scope will say another. I have been told, on no uncertain terms, to trust the SCOPE first. Once you have the system set up and running by using the scope, DRAS can be used as a quick check to tell you how things are holding out between "full" alignments.
In one sentence... Use DRAS as an indicator, not an adjustment tool.

If you have the CP-500 software, beware, you can make adjustments to the system and you WILL F*** things up if you aren't careful. If I came into a theatre to "fix" a CP-500 that wasn't working right and I found that somebody had been hooking up a computer to it and had messed up the parameters, you can bet heads would roll!
 

Somebody decided that the reason they were having such a hard time getting a fix on the Dolby track was that the film was slipping on the sound drum. In order to "fix" that they cut a groove around the inboard edge (circumference) of the drum and inserted a rubber O-Ring in the slot. The idea is to give the drum more traction.

But, Hey! I just do what the boss tells me to do...
 

RORY