This is topic DTS-6AD problem... in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Scott Gorden (Member # 1605) on 04-12-2003, 09:23 AM:
 
Hey guys...

I have an older 6AD unit, one of the first few to come off the assembly line that will play both optical SR and DTS Digital at the same time. Has anyone ever had this happen and what did you do to fix this?

PS: It sound like you are sitting in a football stadium and you also find out how off the delay is really set!!!

Scott
 

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Posted by Darryl Spicer (Member # 711) on 04-12-2003, 10:06 AM:
 
hmmmmmmm how strange, sounds like there may be a bad circuit board that controles where the sound is coming from. It must be allowing all the signal thru puts to stay open. I have not worked with this perticular type DTS system so my comment comes as just a possable suggestion.
 

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Posted by Gordon McLeod (Member # 33) on 04-12-2003, 10:46 AM:
 
I wold suggest checking the revision of the firmware and updating as required
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 04-12-2003, 05:16 PM:
 
If you are hearing analog and digital sound in the surrounds I would be suspect of the D741 DSP Board. If you are only hearing analog in the stage channels (L, C, R) with digital all around I would be suspect of the D744 Analog (Bypass) Board.

You should be able to tell which is the case by turning your main fader to zero. If you can still hear analog sound the problem is most likely with the D744 Analog Board since the bypass fader would be controlling the analog sound on the stage channels. If you don't hear any sound when turning the fader to zero I would try swapping out the D741 DSP Board. If the problem still remains after that, I would then try swapping out the D740 CPU Board.

Caution: The D744 Analog Board has a bunch of jumpers on it to control eq, bi-amping, balance, and crossovers. The D740 has bunch of settings on it that you should backup to a computer before removing from the processor.
 

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Posted by Paul G. Thompson (Member # 655) on 04-12-2003, 07:35 PM:
 
How long have you had this thing in service? And, what kind of analog processer are you using? Did this problem just start?

How in hell is Dolby Digital tied in? I could be totally stupid on this, but if everything is coming through, seems to me there might be a format card in the analog processor that has gone horse shit and summing everything coming into it all at the same time.

Educate me!
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 04-12-2003, 07:38 PM:
 
The DTS-6AD is the analog processor Paul. The 6AD is kind of like a CP-500D. It does the same thing as a 6D but is also capable of SR emulation.

Who mentioned Dolby Digital?
 

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Posted by Paul G. Thompson (Member # 655) on 04-12-2003, 08:37 PM:
 
Excuse me.....I was thinking of the DTS-6D. So sorry. Bad reading on my part.
 

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Posted by Karen Hultgren (Member # 395) on 04-14-2003, 04:17 PM:
 
Scott,

First be sure that optical and digital are really playing at the same time. When in digital, try turning off the exciter and see if the sound improves (no echo). Remember to turn your exciter back on after the test.

When the problem occurs, that format is the DTS-6AD in? Is it both in DTS and analog?

What is the serial number if the DTS-6AD?

Do you have any other DTS-6ADs in your facility? If yes, when you have time to test (I don't suggest intermission but instead, before shows start of after all shows end) and try swapping the DSP (middle) with a known good unit. Run a DTS trailer or the first reel and test to see if the problem goes away. If it does not, try swapping the CPU (bottom) board. One of these boards are the problem.

Please email me what you find along with your telephone number and the shipping address of your theater. I will also need to know who your DTS dealer is.

Feel free to call me at DTS as well (800) 959-4109.

Karen at DTS
khultgren@dtsonline.com

P.S. @ 6:30pm = If it is echo in all formats, then be sure the time delay for the speakers have been properly set on the D744 (top) board. No delay is not correct. See page 4-4 in the manual.

[ 04-14-2003, 08:36 PM: Message edited by: Karen Hultgren ]
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 04-14-2003, 04:54 PM:
 
Please post what you find here too.
 

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Posted by Michael Schaffer (Member # 1204) on 04-14-2003, 05:52 PM:
 
How much RAM does the dts-6AD have?
 

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Posted by Darryl Spicer (Member # 711) on 04-14-2003, 06:29 PM:
 
not the RAM question again.
 

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Posted by Scott Gorden (Member # 1605) on 04-15-2003, 06:13 PM:
 
OK...I didn't think I would get this many replys....

I have switch all 3 cards, it does not matter. The last unit that I had do this, DTS switched out for me.

When it first happened, I blocked the led on the sound head and the echo went away and when I unblocked it, it came back. The only way that I have found to get rid of it was to eject the CDs.

As for the software and firmware I have loaded all the latest and greatest versioin.

I was just wandering if anyone had this problem and what they did to fix it....

Scott
 

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Posted by Paul G. Thompson (Member # 655) on 08-31-2003, 12:33 AM:
 
Our DTS6-AD died in Anacortes. Thge left channel has approximately 30 cycle buzz that sounds like hash noise from a flourescent fixture.

In the last two years, I know of six of these units that were sent back to DTS for repair - some more than once - or DTS just simply sent us a new board. I would like to know if this is an on-going issue with the audio boards.

It appears the symtoms are fixed, but the cause of the symtoms is not. This "buzz" I am speaking of is the only real problem that seems to crop up most of the time. Sometimes simply rebooting the DTS corrects the problem - for a while. Sometimes not.

I have outfitted a CP-55 and a CE monitor some time ago with "D" connectors (including one "D" connector for the automation pulses to be read by the CP-55) to allow a "quick replacement" in event of this type of failure. I had to use it twice in the recent past. Tonight, I had to do it again between shows.

To clarify the situation, the buzz is being generated in the DTS-AD unit itself. There is no question about that.

Does anyone know what is causing these problems in the DTS-6AD? When they come back, they are "fixed" but they don't seem to stay "fixed." Some seem to be right back to the same old game within a year. In some cases it was all channels, sometimes it was only with one or two separate channels.
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 08-31-2003, 03:56 AM:
 
Does the buzz occur while playing back both digital and analog soundtracks, Paul? How about while the unit is in bypass mode.

If the buzz is there while in bypass mode, you can rule out the D740 and D741 boards as the culrpits, leaving the D744 board.

If the buzz is there while in 'SR' analog mode, it could be any of the three, but it'd be a safe bet to rule out the D740 board. Also since the left and right channels use the same DAC on the D741 board you'd probably be pretty safe ruling that board out too since you've only got a buzz in one channel. That leaves the D744 analog board since there is a seperate cross over / delay / EQ for each channel. Of course, the noise could be being picked up anywhere, but I'd start with the D744 board in this case.

Now, if the buzz is only present while playing back digital soundtracks I'd look at the D740 CPU board... but I doubt that this is the case. If you've got buzzing in both analog and digital, I especially doubt that this board is the cause.

Have you got another processor to swap boards with?

You might also want to check the power supply... who knows you might get lucky there.

Also don't forget that the processor settings are stored on the D740 CPU Board. Back them up before playing with that board.
 

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Posted by Paul G. Thompson (Member # 655) on 08-31-2003, 12:37 PM:
 
Daryl, to be honest, I did not check the bypass mode. I didn't think it even existed. However, the noise in the left channel is present on all formats. The last time this happened, the culprit was the audio board. DTS sent us a replacement for another unit some time ago, and it corrected the problem.

I don't have another AD unit to in the area to experiment with.

Yes, I will backup the settings. I learned the "hard way" s couple of years ago when both DTS6-AD's died the same way in another theatre.

Before I fiddle with the unit, I am going to look at the left channel output of that hog. It sounds like a 30hz sawtooth wave, but I am curious as to what it actually is. If I can get a picture of the waveform on my oscilliscope, I'll post it just for grins.
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 08-31-2003, 08:59 PM:
 

quote:

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. However, the noise in the left channel is present on all formats.
It sounds like a 30hz sawtooth wave

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