Film-Tech Forum ARCHIVE: DA20 cutting out

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Posted by Jack Ondracek (Member # 1466) on 06-17-2004, 11:18 PM:

CP65
CAT701
DA20

I just replaced the power supply on this today, since it was a culprit earlier. It ran for an hour, then cut out and did not revert to SR... stayed in digital, no sound. Voltages are fine.

Any suggestions from the tech people here?

Thanks

Posted by Paul G. Thompson (Member # 655) on 06-18-2004, 01:15 AM:

Jack, I wish I would have stuck around there a little longer. Maybe we could have figured it out.

By looking at your setup, I don't think you had an overheating problem. What are all the green LED's acting? Does it all look normal? Did they lock up, go out, or what?

One thing you could do....shut the power down and re-seat your cards - one by one. When you pull them out, inspect the edge connector for corrosion and foreign deposites that could make a bad connection.

That's all I can think of. It could be a board failure, but which one - I flat don't know.

However, one thing comes to mind. You did mention the Molex plug on the power supply showed signs of overheating if I recall correctly. Did you inspect the condition of the pins for corrosion, and is there a chance the plug may have gotten hot enough to ruin a solder connection? Worth looking into... [Smile]

Edited for typo and to have the post make more sense.

[ 06-18-2004, 02:37 AM: Message edited by: Paul G. Thompson ]

Posted by Ken Layton (Member # 133) on 06-18-2004, 01:46 AM:

Try cleaning the card edge connectors.

Posted by Mark Gulbrandsen (Member # 72) on 06-18-2004, 03:07 AM:

There are no edge connectors in the DA-20. Just large milti- pin plugs on the ends of the pcb's that plug into the mommie board. Cleaning them is definately NOT necessary!!

Be sure the problem is not in the digital scanner first. Simple to check... just put a scope on the DA-20 video test point and trigger the scope from the clamp t.p. below that. Be sure there is about 3 to 4 volts of video p to p..

Very few of the DA-20 supplies actually fail, its usually the molex connector that gets crispy! I get rid of the Molex's and solder the wires directly to the board. Never had a failure after doing it that way.

Mark @ CLACO

Posted by Paul G. Thompson (Member # 655) on 06-18-2004, 03:13 AM:

Oops....sorry, Mark. My bad. [Frown]

Hey Jack...if that drives you nuts, let me know. If you don't have a scope, I can bring mine down and we can try what Mark suggested if you so desire.

Mark, is that a possibility that the fried molex connector did damage the pins on the board? Maybe burned up a solder connection?

Here is another possibility, although it might be a shot in the dark. Can you monitor the output of the DA-20 separately before it interfaces with the CP-65? Maybe the DA-20 is working OK, and the signal is being dumped by the CP-65. Just a thought.... [Smile]

Posted by Jack Ondracek (Member # 1466) on 06-18-2004, 03:26 AM:

Thanks for the ideas, everyone. I'll check on it tomorrow. I probably should have noticed whether the cards locked up, since that was what was going on before. However,the last problem was in the 5v supply, so this may be something different.

Paul... glad to see you made it back home ok. I actually changed that supply after you left. Darn box dumped on Cheryl after I headed to the Drive-In.

Mark is right... no edge connectors on those cards. That was something I looked into on the last go-around, when the Molex connector really was the problem.

Mark... if the 701 was a problem, wouldn't that show up on the error readout? I'm pretty much always in the 1-3 region.

The current power supply just came out of the box. As the processor is acting the same as it did before, I'm assuming I can discount the supply as the problem (wish I'd figured that out before I bought the darn thing!).

The aggravating part of this is that it's an intermittent problem... not at all predictable. It might run fine the whole day... or not.

quote: Paul G. Thompson
Maybe the DA-20 is working OK, and the signal is being dumped by the CP-65. Just a thought....

Yah... I can scope that where it enters the 65. When it's gone, all channels are down.

Don't know if this means anything or not... but if you cycle the power on the DA20, it will 'boot up' and appear to be working, but you also have to take the CP65 out of digital and back in before you'll hear anything. That may be normal, but it made me wonder if there was something fishy in the signalling

Anyhow... it's mostly speculation at this point. I'll look it over some more tomorrow. Thanks again.

Posted by Mark Gulbrandsen (Member # 72) on 06-18-2004, 08:14 AM:

Jack,
Did you replace the power supply cable when you replaced the power supply?

Mark

Posted by Jack Ondracek (Member # 1466) on 06-18-2004, 12:46 PM:

Yes. The power supply came with a new cable attached.

I'm not there right now... (and the manual is at the theatre).

Cheryl says the display has a "C" on it.

Posted by Peter Hall (Member # 695) on 06-18-2004, 02:05 PM:

Surely if it was a reader problem it would defaut ? Check the ground conns on the PSU

Posted by Paul G. Thompson (Member # 655) on 06-18-2004, 02:21 PM:

If the display has a "C" on it, maybe it is "E" minus the two --'s. [Big Grin]

I don't know what error code "C" is. Maybe the book will say. But whatever it is, it does sound like an internal failure of some sort. Why it is not defaulting back to SR"A", I don't know. I am not very familiar with the DA-20, So I am also grabbing for straws.

Posted by Jack Ondracek (Member # 1466) on 06-18-2004, 04:11 PM:

quote: Paul G. Thompson
If the display has a "C" on it, maybe it is "E" minus the two --'s

...something I've personally been missing for some time! [Confused]

...friend of mine checked with Dolby. They think it's the processor board, and the indication is a checksum error.

Posted by Ferdinando Innocenti (Member # 2477) on 06-18-2004, 04:16 PM:

You have measured voltages on the Cat. No. 670, isn't it? So, if the problem with Molex connector is now OK, you could control the serial number of your DA20; if it's below 502260, it can be a software problem on cat. 611. It's a loose of synchronization with CP65, but DA20 should show a normal error rate, not a "C"... Are you sure of "C" rate?

Nando

Posted by Jack Ondracek (Member # 1466) on 06-18-2004, 04:25 PM:

On this, I'm not sure. Dolby thinks its a board problem, so I guess it's a matter of changing it out. I haven't done much component level service work on those boards! [Big Grin]

Guess we'll see on Monday, when the replacement comes in.

Thanks, everyone, for the ideas and suggestions.

Posted by Don Sneed (Member # 955) on 06-20-2004, 08:32 AM:

my problems with Dolby digital has been with the video card Cat. #670 in the DA-20 & CP-500, I had one in CP-500 that would heat up & stop reading, I found it by accident, the booth was hot, AC was not on, I turn on a fan on a stand, pointed it at me & with the CP-500 door open while I troubleshoot & the problem went away, until I closed the door, long story short, overheating video card.

Posted by Steve Guttag (Member # 268) on 06-20-2004, 02:02 PM:

Yeah, check out that card...there is a TO-220 package voltage regulator on it...no heat sink...it just uses the card itself. On the underside of the card you can see how hot it gets by the discoloration.

Steve