Getting the best from DTS	All About DTS

If you have problems with your DTS system including sudden changes in the sound level, wobbling in the sound or switching from digital to optical sound during the film, please follow the following steps to identify what is the cause of the problem. In a majority of cases, the problems are not caused by the CD-ROM disc.

Does the timecode light go off for a few seconds before the system switches to optical sound? If so, go here. If you hear a sudden drop in sound level, it probably means that the system has switched to optical sound. The timecode light (LED) is the large green light which is on the timecode reader.

If the timecode LED does not go off before the system switches to optical, the problem is with the discs or the CD-ROM drives. Does the system always switch to optical at the same places in the film? If so, the problem is with the discs. To reconfirm, exchange the two discs, putting each in the other CD-ROM drive, and check if the problem happens at the same places in the film. If it does, the discs have been damaged or are defective. At this point, you can try to wipe the disc with a soft, lint-free cloth and try this test again. If this does not solve the problem, then the discs are defective. PROBLEM IDENTIFIED. Ask for disc replacement. Call your local film distributor or Real Image.

If the system does not always switch to optical at the same spot, the problem is probably with the CD-ROM drive. Exchange the two discs and the problem should happen at different points in the film. This will confirm that the problem is with the drive. PROBLEM IDENTIFIED. Ask for a replacement drive. To check which drive is defective, see the LEDs on the drives. The LED on each drive blink when the drive is reading the disc. At the points where the system switches to optical, the drive being used is the defective drive.

Does the timecode light blink often? It should not flash more than two or three times a minute. If it goes off or flashes heavily only at certain specific portions of the film, then the problem may be due to a defect in the print. PROBLEM IDENTIFIED. Ask for the reel to be replaced by your local film distributor.

Try another film or the DTS test film. If the timecode does not blink much with this film, then the problem is with the other print. PROBLEM IDENTIFIED. Report problem with print to your local film distributor.

If the timecode LED always blinks often, then the problem is with the timecode readers or the projector's mechanical alignment. If the blinking happens only on one projector, then the problem may be with that timecode reader or that projector's alignment. The possible causes are Film instability or speed problems, electrical noise or grounding problems or DTS equipment problems.

Film Instability or Speed: Check the speed of the projector. It should be between 23fps and 25 fps. If the mains frequency drops below 50 Hz, it will cause a corresponding speed drop in the projector as well. Try running the system on the theatre's generator with the frequency set correctly at 50 Hz. If the timecode instability disappears, then the problem is due to the projector running slow or fast due to the incoming mains frequency. This problem can be corrected mechanically by modifying or changing a gear wheel or electrically by a low cost device. Your DTS unit can also be modified by Real Image to handle greater mains frequency variations. Make sure the Aux Roller on the timecode reader (black roller on adjustable arm) is installed and provides as much wrap as possible on the silver roller. The adjustable arm should be pivoted towards the cable end of the timecode reader as much as possible. Also check the film's run through the timecode reader. If it is aligned correctly, the film should touch both sides of the roller with equal pressure without buckling. Gently squeeze the edges of the film between two fingers as it enters the timecode reader. Pull back slightly and allow your finger to act as shock absorbers. Repeat this on the exit side of the reader as well. If this stabilizes the timecode reading, then try to find the source of the instability. The possible causes are: Bad roller(s) Bad projector belt, gear or sprocket Too little back tension Too much tension Bent or warped reel Bad reel clutch

Electrical Noise or Grounding Problems: Electrical noise on the timecode inputs can confuse the timecode reader circuit causing the LED to blink and in some cases cause sound wow, edits and dropouts. First, make sure that the projectors and the DTS unit are properly grounded. All new reader cables have a shield wire shrink wrapped to the jacket on the timecode reader end. Cut away the shrink wrap and connect the wire to one of the screws that holds the reader to its bracket. Check if this improves timecode reader stability. Make sure that the shield of the timecode cable is connected to conductive connector shells at both ends. A quick way to check grounding is to attach a new wire between the timecode reader's holding screw and any metal screw on the DTS processor. Do not run timecode cables along with power lines, over tube lights or near motor controllers or arc rectifiers.

DTS Equipment Problems: Ask for a good timecode reader and check if this fixes the problem. If only one projector has a problem, try exchanging the two timecode readers. If the problem moves to the other projector, then ask for a new timecode reader.