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CP650 Digital Cinema Processor User’s Manual Troubleshooting
4-2
If One Channel Fails or Is Distorted
If one channel in your theatre system fails or sounds distorted, take the following
steps:
1. Switch the CP650 to Bypass mode by pressing the front-panel bypass power
switch. A mono signal is fed to all three screen channels. If the problem in one
channel persists, the power amplifier or speaker for that channel is probably at
fault. If the problem is not in the Center channel, switch the faulty amplifier off
(be sure that the amplifier is not shared with the Center channel) and finish the
show in Bypass mode.
2. If you are showing a mono film and the Center channel has failed or is distorted,
switch the CP650 to Bypass mode so that the mono signal is fed to the still-
functioning Left and Right channels. Turn off the power amplifier for the Center
channel.
If Switching to Bypass Mode Does Not Restore Sound
1. Check the film reader LEDs or exciter lamps, the fader setting, and the mute
button. Make certain that all components—including power amplifiers—are
receiving AC mains power.
2. If the bypass power appears to work (front-panel bypass power button glows red),
open the front control-panel access door and check if the signal present lights are
flashing. If they are, and sound is still not available, check for AC power to the
power amplifiers.
3. If the signal present lights are not flashing, the Cat. No. 772B circuit board may
be faulty. Call your service engineer.
If You Hear Extraneous Noises when Playing a Digital Film
1. Press the format 05 front-panel button to play the film in analog Dolby SR format.
2. If the noises persist, switch the CP650 to Bypass mode by pressing the front-panel
bypass power button.
3. If the noises still persist, check the power amplifiers, as it is unlikely that both the
digital and analog parts of the system have failed.
Excessive or Inappropriate Sound from Surround Speakers
As an emergency measure to continue the show, switch off the surround channel
power amplifiers. Contact your service engineer to determine if the problem is related
to the film itself or to the theatre sound system.
4.1 Troubleshooting Chart
Table 4–1 may be helpful in finding sound problems with your system.