Film-Tech Forum ARCHIVE: DTS troubles

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Posted by Chris Medley (Member # 2145) on 02-14-2004, 08:19 PM:

I had a problem today where my print of Highwaymen lost the center and surround channels. I checked and cleaned the DTS reader and that didn't work. The film was threaded properly and the disk was in the tray. The unit seemed to be working fine. I kicked it into stereo and turned of the unit. I waited like a min and then turned it back on. The DTS kicked back on and I was getting good sound out of all the channels. I was thinking maybe the power supply was going out on the unit and it was causing some of the channels to drop out....any thoughts

Posted by Kyle Watkins (Member # 986) on 02-14-2004, 08:33 PM:

We had this problem a while back we only lost the center channel though, turns out it was a bad play back board.

Kyle

Posted by Jack Ondracek (Member # 1466) on 02-14-2004, 08:33 PM:

Processor? Amplifiers? Monitor?
Did you get your channels back when you went to stereo?

The two simplest channel-loss problems I've had were loose screws on a CP65 spade lug strip, and my current QSC 1400 issue with noisy pots. Still, losing 2 channels would be curious... UNLESS your center and surrounds are running off the same amplifier. ??????

Posted by Gordon McLeod (Member # 33) on 02-14-2004, 08:35 PM:

"I checked and cleaned the DTS reader and that didn't work"
Since the time code conatins no audio how does one expect cleaning the reader would resotre a lost channel
What you don't mention is this a DTS 6 or 6D
I have had several DTS6 have output relays fail

Posted by Mark Gulbrandsen (Member # 72) on 02-14-2004, 09:40 PM:

What kind of analog processor do you have and were all the channels ok in analog stereo or not?
As for the DTS..... First check and be sure that the fan in the power supply is operating. I've had fan failures cause the unit to overheat and some of the DAC's shut down. DAC's are so,metimes very temperature sensitive. Bad fans are a very common problem in DTS units, especially older units. If you find that its stopped just get a new fan. They're under 10 bucks.
I've yet toahev failure of any board in a DTS 6 since they came out. Just drives, power supplys, and fans.

Mark @ CLACO

Posted by Chris Hipp (Member # 1788) on 02-15-2004, 02:01 AM:

Time to steal this thread.

DTS 6D with an Ultra stereo JS200

When the DTS unit is turned on, the JS200 goes straight to Digital ext and will not change out of it until the DTS unit is turned off and the JS200 is turned off and back on. will not read any information. I am not sure if it is not reading at the reader or if it isnt reading the drves. It does not matter where the discs are, it will do the same thing.

The same JS200 works fine with my other DTS6D so I am sure the problem is with the DTS unit. Any ideas?

Also, is it dangerous to switch out cards with a DTS unit? That is how I usually narrow down the problem but I know very little about DTS.

Thanks

Posted by Michael Schaffer (Member # 1204) on 02-15-2004, 03:19 AM:

The DTS processors have little capacitors as filters behind the automation pin connectors. Sometimes these blow up, then the DTS locks the main processor into a certain format. There is nothing you can do to repair that yourself. You have to send the board in for repair. You can take the board out and look at the traces. When you have figured out which belong to which pin, then you can measure the resistance between pin and trace to see if one of the automation pin capacitors has gone bad.
But sometimes it is also a problem with the automation interface board or cable, like a bent pin.

Why are you not sure whether the timecode is read or not? That is indicated clearly by the LEDs on the reader and the processor.
When a CD-ROM drive is active reading a disc, then the green LED flashes very rapidly. When it is either dark or continuously brightly lit, then the drive has a problem reading.
The setup disc is available for download here on the homepage. This will help you troubleshoot the unit further.

Posted by Mark Gulbrandsen (Member # 72) on 02-15-2004, 11:06 AM:

"DTS 6D with an Ultra stereo JS200"
_________________________________________________________________

Time to steal it back.......

All the above mentioned DTS problems are notwithstanding the plague of the USL processors many inherent channel dropping problems. Such as the relays on the eq cards failing, or the sound bypass switch and its crappy 2 cent contacts which go intermittent without warning. The good news is that lately USL is considering eliminating that bypass switch and I hope they do. Seems like I've spent half the last 25 years yanking crappy switches and bypassing relays......simple things which if designed right don't fail in the first place.

Mark

Posted by Chris Hipp (Member # 1788) on 02-15-2004, 12:34 PM:

I dont know about the timecode because I haven't hooked it up in a while.

Posted by Michael Schaffer (Member # 1204) on 02-15-2004, 12:58 PM:

Has bypassing the relay on the EQ card any negative side effects? How do you do it? I have a USL power supply which intermittently sends a very loud hum into the rest of the system, is there an easy fix for that too?

Posted by Mark Gulbrandsen (Member # 72) on 02-15-2004, 03:27 PM:

MIchael,
That hum might be either a bad power supply or a bad power backup switch. That switch is also part of the USL plague! If ther eis one....on any USL processor for that metter REMOVE IT!Simply remove it from the pcb and wire bypass the two front poles that are closest to the front of the supply itself keeping the supply on premanent,y. Even USL has permanently elimninated this switch.

Mark @ CLACO

Posted by Gordon McLeod (Member # 33) on 02-15-2004, 03:37 PM:

I usually end up bypassing the relays on the USL eq boards

Posted by Michael Schaffer (Member # 1204) on 02-16-2004, 05:01 PM:

What are the exact symptoms for the bad power backup switch? In our case, the processor sometimes (every other couple of days) produces a very loud hum and the signal LEDs on the noise reduction card go all the way up. After checking that the optical preamplifier was OK (and it does it in all formats anyway), I swapped power supplies and also the noise reduction card across 3 cinemas to isolate the bad component.
It turned out that the loud hum followed the power supply. It usually goes away after resetting the processor. Can this be caused by a bad backup power switch?