Film-Tech Forum ARCHIVE: DA-20 How to set the A-Chain

This is topic DA-20 How to set the A-Chain in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Bill Langfield (Member # 818) on 08-25-2004, 03:49 PM:

Ok, this a lame question, the topic and subject matter will proberly need editing.

But at this point in time Im not in a postion to read a manual or do a FT search (which I DID try last night) and Im tired as hell. (its 7am, and I just finished a double, thank god I have today off, plus watching the Olymics, most good stuff is not here till 4.30am. Then there has been this crap on the radio all night about a UFO travelling over most of this state - No doubt just a high up comet)

Oh the DA-20 and my A-chain question.

Is there a way of working out how to set the 'levels' without an osiloscope? Is there any levels to adjust? Can I do it with a DMM?

If I lace through the cat 700 reader, I get the F.
If I bypass the reader I get '-' , so the DA-20 must be seeing something.
If I turn the reader off I get the '-'

So Im GUESSING the thing is working but just not getting a strong enough (video) signal somewhere on the chain.

The 'tech's' decided it was 'just' the power supply, which I agreed with, because when turning it on, all the LED's, and mean all of them, just flashed on and off like a light show. With the new power supply everything looked OK, but the thing still doesnt work, as described above.

Posted by Kyle Watkins (Member # 986) on 08-25-2004, 05:18 PM:

Have you replce the bulb, and if no messed with the aligment can turn up the voltage by the control on the inside the back cover. I done it this way( not the recomeded way) until i got my self a oscillscope.

Posted by Aaron Sisemore (Member # 145) on 08-25-2004, 07:18 PM:

quote: Bill Langfield
Is there a way of working out how to set the 'levels' without an osiloscope? Is there any levels to adjust? Can I do it with a DMM?

There are no user-adjustable items on a DA20 ouside of automation control and delays, and nothing that would affect the way the reader operates.

Take out the bulb. Look at the reflector, it should be mirror-clear. Regardless of how bright it is when lit, if it has ANY fogging of any type on the reflector, chuck the bulb and install a new one (GE type EPT or Osram type EXZ are preferred)

If you haven't monkeyed with any of the lateral, focus, or azimuth adjustments on the reader, things should come back to something resembling normal after the bulb change.

If you have tinkered, a tech call (with a scope) will be necessary to properly rectify the problem.

-Aaron

Posted by Chris Hipp (Member # 1788) on 08-25-2004, 08:57 PM:

I went from F to 0, 1s and 2s just from changing the bulb. definitely do that first

Posted by Dean Kollet (Member # 1789) on 08-25-2004, 09:11 PM:

when u get an F or when you get the - do the Green Digital and Amber Analogue LEDs light up?

Posted by Mark Gulbrandsen (Member # 72) on 08-26-2004, 10:43 AM:

"I went from F to 0, 1s and 2s just from changing the bulb."
_________________________________________________________________

That only happens in Texas! Since SRD has appeared I've only ever seen one print with one reel of zeros, the other five reels had 2's and 3's and that was a world premiere print I ran a couple of years ago. Typically we see 3's, 4's and 5's in this part of the world, many brand new prints even run through with solid 6's.

If you're still having trouble after you change the lamp one thing to check is the four rows of green LED's under the front cover. All should be lit evenly and all should stay on 95% of the time, a couple of LED's blinking quickly is acceptable and is just an indication of normal errors. If they are all out or all blinking rapidly then a tech will be required to reset the reader, or diagnose whats wrong with the DA-20. Also check the edge of the lateral guide roller, see if its shiny alumnium colored instead of the nice Black hard coat it is supposed to be. I have seen many worn ones lately and that requires a re-alignment of the CCD camera board to compensate for the wear and resultant lateral shift of the film. When you have the back off to change the lamp its also a good idea to check the white molex's on the power supply board as almost all 700's around here have had(or would have soon had) failure of the Molex connectors. Just remove the connectors from both the board and the wires and solder the wires directly to the board. If you do this you will likely never experience a failure of a CAT 700 power supply..... Unless of course lightning is your enemy....

P.S. Bill,
It is normal for all four of the rows of green LED's to blink rapidly when no film is threaded in the film path. Both the DA-20 and CP-500 will exhibit this. Cover the camera lens or light source and the blinking will stop.

Mark @ CLACO

Posted by Darryl Spicer (Member # 711) on 08-26-2004, 11:24 AM:

I agree it must be a Texas thing. I pretty much see 3's 4's and 5's on our unit.

Posted by Tim Reed (Member # 137) on 08-26-2004, 01:11 PM:

quote: Mark Gulbrandsen
That only happens in Texas! Since SRD has appeared I've only ever seen one print with one reel of zeros

Must be the way you all are setting them up. I routinely got 0's (on trailers, yet, running Cinemeccanica V5 basement readers), when I was doing the service thang in Boston.

Posted by Brad Miller (Member # 2) on 08-26-2004, 01:20 PM:

Mark, I only see 0-1s at theaters that run cleaners with FilmGuard. We ran 0-1s on Christie P35GPS basement readers in Colorado, so it's not just a Texas thing. I think it's more of a film handling issue. If there is ANY shedding of the print, the track will read higher with each pass of the film. This isn't an absolute blanket statement, for older well worn projectors (V5s, Centurys, etc) are pretty gentle on film as well, but even with that virtually everyone reports the error scale gets knocked down a couple of points on used prints once they are passed through FilmGuard.

Start keeping score next time you see a high error rate and let me know what lab you see it coming from. There is a pattern. Still a high error rate is "3".

Posted by Chris Hipp (Member # 1788) on 08-26-2004, 01:29 PM:

quote:
That only happens in Texas!

We had a print called "a day without a mexican" I do not know if it was a very big release or not. I kid you not, the entire print ran and never got above a 1. This was with two readers but one prcessor (on a roll around cart), did the same on both.

Of course, Brad said he did some of the sound install at my theater and that could be why. [Wink]

Posted by Brad Miller (Member # 2) on 08-26-2004, 01:58 PM:

Nope, the auditoriums I did were all SDDS, one or two of them were definitely SDDS-8 to my recollection.

Posted by Mark Gulbrandsen (Member # 72) on 08-26-2004, 03:26 PM:

I guess I would agree Brad except that I've actually tried using some of those actual films to tweek the readers down to perfection. It just is that bad around here. One of the funny things is that the film that was running all 6's was with a BACP reader on a DA-20 so one can imagine that with a CAT 700 and CP-500 that it wouldn't have played back at all. I will make a log though as I go around and we'll see if it proves or disproves anything. I also agree that 3 is a high error rate and is what I used to see back in the Midwest area and out here when I first got here. Its gotten really bad in the last few years though. Thats why none of our customers really want to buy SRD any more. I have not noted any unusual projector problems either and I service such a wide variety of macines out here and see this happen in many places.... on Christies, on Simplexs, Centurys, Norelcos etc. I do see an ocasional low error reel in a print but its never consistant through the entire print. Now perhaps you can more understand why I've pretty much abandoned SRD.

Tim, It was about the time you were laid off that the prints started reading high error rates out here. I really can't see that its the setup I'm doing wrong because I do on occasion see a very low error rate. Geez, I've setup hundreds of these things over the years.

Mark @ CLACO

Posted by Ferdinando Innocenti (Member # 2477) on 08-26-2004, 04:46 PM:

Bill,
if you like, you can download Windras, a Dolby software that gives you the opportunity to watch at the quality of the print and the alignment of the reader.

You need a PC and a M/F DB9 cable (pin to pin); if you are not sure, it's better not to modify the reader alignment, but it is possible to reach a not so bad result with it.

But scope is the best for perfect digital reading!

Ciao
Nando

Posted by Dean Kollet (Member # 1789) on 08-26-2004, 08:09 PM:

I'm going to that Dolby Training Seminar and they said to bring a cable with my laptop, is that the cable? Can I also use it for SDDS?

Posted by Tim Reed (Member # 137) on 08-26-2004, 09:01 PM:

quote: Mark Gulbrandsen
Geez, I've setup hundreds of these things over the years.

Mark, yes, I know you have. I was just ribbin' ya. [Wink]

Too bad the QC has denegraded since I've been out of the loop.

Posted by Brad Miller (Member # 2) on 08-26-2004, 10:08 PM:

Dean, yes same cable assuming you buy a null converter to put on one end of it for using with SDDS. Otherwise just buy two cables and mark them DOLBY or SONY.

I think Mark has been smoking some of that I-30 stuff. I haven't seen SRD track printing quality get better or worse over the years. It's always been fine.

Posted by Mark Gulbrandsen (Member # 72) on 08-26-2004, 10:29 PM:

There's no I-30 here, just I-40 and I-15!

Mark

Posted by Dean Kollet (Member # 1789) on 08-26-2004, 10:33 PM:

excuse my ignorance....but what two cables do I need? like part numbers or specs....male/female/which sides/etc

Posted by Daryl C. W. O'Shea (Member # 1303) on 08-26-2004, 11:19 PM:

Dolby: Straight thru 9 pin serial male to female.

DTS & SDDS: Cross over (null modem) 9 pin serial female to female.

You can buy them at any computer shop, Fry's, Best Buy, whatever. Or you can make your own.

Posted by Dean Kollet (Member # 1789) on 08-26-2004, 11:51 PM:

same cable for DTS and SDDS?

Posted by Robb Johnston (Member # 239) on 08-27-2004, 12:41 AM:

except for a null modem on the SDDS (both 2000 and 3000 and 3000 reader calibration)

Posted by Ferdinando Innocenti (Member # 2477) on 08-27-2004, 01:02 AM:

Dean,
the cable is not the same for SDDS: for Dolby connections it's a pin to pin cable (1 to 1, 2 to 2, and so on), for Sony connections is a null modem cable; loook at here for a scheme: http://www.loop-back.com/null-mod.html

Ciao
Nando

Posted by Josh Jones (Member # 447) on 08-27-2004, 03:16 AM:

We run late run art stuff up here, used to track 5-6 regularly. used beat up print of The story of the weeping camel is tracking 0-1-2 here, with film guard of course. I also noticed a difference at the house when I started using the stuff.

Meanwhile at the plex, the lowest I see is 3, many are hovering around 6.

Josh

Posted by Michael Schaffer (Member # 1204) on 08-27-2004, 03:44 AM:

To add to the confusion, for the SDDS processor you also need a gender changer for the null modem cable.

Posted by Mark Gulbrandsen (Member # 72) on 08-27-2004, 07:48 AM:

You guys and all your cables [Roll Eyes]

. All you really need is one straight through serial cable and a null modem adaptor that you can buy at Rat Shack. This makes for less of a tangle in your sound case.

Mark @ CLACO

Posted by Ferdinando Innocenti (Member # 2477) on 08-27-2004, 10:39 AM:

Mark, sorry for my English: "straight through serial cable" is the right way to describe a "pin to pin" cable?

Thanks
Nando

Posted by Mark Gulbrandsen (Member # 72) on 08-27-2004, 07:52 PM:

Fernando, No need to appologize for your English. Its actually VERY good! "Straight through" is just another way to say it. "Pin to pin" is also good.
I have to wonder how many people in other countries are worried about posting here because thay may think their english is bad but in reality it is very good.... I'd bet there are many!
I would like to see more people from other countries post here.

Mark @ CLACO

Posted by Bill Langfield (Member # 818) on 08-31-2004, 04:50 PM:

Thanks for the tips, the one's that stand out are the 'Replace the bulb, I went from F. to 2-3' or something like that.

I said to the 'tech', "I have asked some 'friends' about it and they suggested replace the bulb." He just says "no, it was the power supply, I tested the voltages" - whatever that means. (I don't know at that point if he was refering to the da-20 or the cat700). I said "well its not working". As far as he knew the thing was fixed. But everyone was bypassing it and had the cat 700 turned off.
I'm cutting very long story short here, believe me.

Only 1 of the 30 screens (spread over three close locations of the same company) has a cat700, the rest are basement, oh 2 are DTS (dont ask) on Vic5's.

Problem, we have no spare bulbs, so I had a look at the bulb currently in the reader, I couldn't really see any fogging or dis-colouring, and having no new bulb to compare it to, I decided to rotate the lamp 45 degrees and also make sure it was seated properly. (Hmm, I know where to get a new bulb, YOU reading this BRETT?? - Better hide the spares)

Next session all I was getting was the '-' and thought F&*k, and thinking at reboot all I'll get is F.

But WHOA at reboot, it was coming in at 6. jumping to F then settled to 5.5/5.0 or even as low as 4. However it would flash to F. for a milisecond too many times my for liking to let the show actually run in SRD.

Next session it started '-' again, but after a re-boot sat on nice 4-5, but still jumped to 6. then f. at times.
(The print was a quite new Peter Sellers, not a 9/11 that I don't think anyone can run in SRD anymore)

One note though, the tiny LED's on the DA-20 in the top right (L-C-R-LS-RS-SW) barely ever flash, all the other DA-20's (with basement readers flash like crazy), is that another indication the bulb is at fault?

So the new bulb idea sounds right to me. If only I could convince the 'tech' of that.
The rebooting it (the DA-20) each show seems strange though.

I'll do more research, when I'm next there to put a in new bulb. (hello BRETT - Hide 'em mate)

Posted by Brad Miller (Member # 2) on 08-31-2004, 05:42 PM:

Yes Bill, change the bulb. The worst thing that could possibly happen is that it did not fix the problem and you now have a spare. oooooh, what a horror!