Installation manual

Dolby
®
Model CP650 Troubleshooting Chart Maintenance and Troubleshooting
9-11
Symptom Probable Cause Recommended Action
FADER PROBLEMS Front-panel fader knob has no effect. External analog remote fader pot selected.
Select front-panel (“local”) fader by pressing the left menu button to show the Fader Setting menu, then turning the front-panel knob to display “Local”. Press the OK button. This will restore control to the main front-panel fader and any digital remotes that are connected.
Fader level display changes when no change of CP650 front-panel fader has been made.
A remote digital fader is being operated. A format with a different fader setting was selected. Analog remote fader is selected and being changed.
Note: Digital remote faders are always active. Disconnect the remote to disable it.
CONTROL PROBLEMS CP650 won’t accept a format selection, and displays a “Format Unavailable” message.
CP650 doesn’t have the optional modules needed for that format, or that part of the system is not working. For example: Format 10 requires the Dolby Digital Cat. No. 773 board. Formats 13, 80, or 81 require the Cat. No. 790 or 794 Dolby Digital Surround EX board, or Cat. No. 778 Digital I/O board. Digital reader LED not working, non-Dolby Digital print being played, film not threaded correctly in reader, reader failure.
Obtain and install the necessary circuit boards. If they are already present, ensure that they are firmly seated in their connectors. Verify that the LED (or exciter lamp) in the digital film reader is on. Verify that the print you are playing is correctly threaded through the digital reader and that it includes Dolby Digital information . If the CP650 accepts a Format 10 command, the digital sub-system is probably still working.
Front-panel display reads “Reverted!” when Format 10 is selected and stays in optical Dolby SR.
No Dolby Digital data available, not a Dolby Digital print, projector not running, or data blocks badly damaged.
Review each possible cause.