Film-Tech Forum ARCHIVE: da20 error display question

This is topic da20 error display question in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=007406

Posted by Carl Martin (Member # 1146) on 08-20-2005, 03:46 AM:

so we were running another one of those lovely trailers with an srd track consisting of silence (tony takitani this time). when it played, the da20 would display the error rate numerals as normal, except that the bottom horizontal led segment of the "8" would flash on and off, while the other 6 segments would comprise the numeral as usual. this happened on both a flat and a scope version of this trailer.

i couldn't find any mention of this flashing led segment in the da20 installation or user manual. am i correct in assuming that this is something that happens with a silent srd track? but why then haven't i noticed it in other instances of silence, like during the ratings band of a trailer?

carl

Posted by Michael Schaffer (Member # 1204) on 08-20-2005, 05:01 AM:

Your normal error rate is 8? Hmmm...

Posted by Carl Martin (Member # 1146) on 08-20-2005, 05:08 AM:

err, no. i don't think i've ever even seen it hit 8. i was just indicating the layout of the led segments, what it would read if they were all on.

carl

Posted by Ken Jacquart (Member # 369) on 08-20-2005, 01:51 PM:

If you have another DA20 in the booth, swap the Cat 673 card (the one with the error display) and see what happens.

The fact that you have no sound is strange... there was a problem years ago with molex connector pins burning on the power supply connector and consequently causing the 5.0 volt rail to drop. This resulted in some strange things (including no auido). Measure the 5 volt rail with a digital volt meter on the test points located on the Cat 670 card. If it's below 4.84 volts (or so), then you probably have this particular "molex" problem.

Posted by John Hawkinson (Member # 1135) on 08-20-2005, 07:12 PM:

In case it's still unclear, I believe Carl is saying he sees a flashing underscore.

--jhawk

Posted by Louis Bornwasser (Member # 3063) on 08-20-2005, 07:42 PM:

Ken; we had a good number of older DA-20's that had the reboot circuit voltage set too low. If power was interupted and the rails dipped sound would stop and the system would not reboot. Apparently wrong value of zener diode was used in production error. Louis

Posted by Mark Gulbrandsen (Member # 72) on 08-20-2005, 09:05 PM:

quote: Louis Bornwasser
we had a good number of older DA-20's that had the reboot circuit voltage set too low. If power was interupted and the rails dipped sound would stop and the system would not reboot. Apparently wrong value of zener diode was used in production error. Louis

I believe it was these power supplies that Lonnie Jennings traveled all around and changed out at N/C to the theatre owners.... So there shouldn't be many if any of them still out there. To cure the Molex problem the best cure is to eliminate the Molex all together amnd solder the harness dorectly to the P.S., I've even seen failures of the three sided molex pins in the later style connectors.... I always say that any connector present in any system is just another time bomb waiting to happen.

Mark

Posted by Ken Jacquart (Member # 369) on 08-20-2005, 11:27 PM:

Yes, there was a problem with the original style Molex female connector pins. The original style mated only with one side of the square male pins of the power supply. They would tend to burn up after years of use. Then we switched to a female connector that would mate 3 sides to the connector pin and thus distribute the current better. When I've seen this problem in the field, I've generally soldered directly to the pins.

If the problem is a flashing error display segment, then I would still suggest to try and replace the Cat 673 card itself.

Posted by Carl Martin (Member # 1146) on 08-22-2005, 06:14 AM:

ken, there's no functional problem with the da20. there was no sound because the srd track on this trailer consisted of silence (it happens).

i take it then that the "blinking underscore" on the error display is not a design feature?

sorry, i can't go digging into the innards of the da20, or i will have my own innards dug into.

carl

Posted by Carl Martin (Member # 1146) on 09-05-2005, 04:50 AM:

ok, different trailer with a silent srd track ("dear wendy" this time), played on a much newer da20, same result: flashing led segment in the error display. it sure looks like an underpublicized feature of the da20.

carl

Posted by Steve Guttag (Member # 268) on 09-05-2005, 09:51 AM:

I seem to reall seening this blinking underscore on some Dolby snipes (Train, City...etc).