Operating instructions

1-5
be sure that the projector is not selected. If you are playing an
optical film print, be sure that there are no signals present from
any of the other sound sources.
• Even when a stereo print is playing, a summed mono signal is fed
to all the screen speakers. Thus, you can switch to the bypass
mode to keep the show going if one of the power amplifiers or
speakers fail.
• The Dolby A-type noise reduction circuitry, Spectral Recording
processors, 2:4-channel decoder, screen speaker equalizers,
surround equalizers, and subwoofer circuits are out of the signal
path.
• The front panel mic switch acts as a "push to talk" key rather than
a "push on, push off" switch. If there are emergency
announcements to make, the film and background music should
be turned off so that the audience can hear the announcement
above the other sources of sound.
If the unit has entered bypass mode due to a failure in the main power
supply or the main power source, then the front panel LEDs will be off
except the projector select and bypass LEDs. The unit performs in
exactly the same way as if the bypass switch were selected as described
above.
In the event of bypass operation, be sure to follow the troubleshooting
procedures and call your trained service engineer, if necessary, as soon
as possible.
NOTE
The CP45 will not operate even in the bypass
mode if there is a fault in the mains supply
to the bypass transformer and may not
operate if there is a fault in either the Cat.
No. 514 optical preamp card, the bypass
circuitry section of the Cat. No. 510 on which
it is mounted, or the bypass power
transformer itself. It is strongly
recommended that a spare of both of the
cards and the transformer block be kept on
hand for substitution in emergencies. If the
theatre is equipped with film platters and
the unused projector input on the rear of
the CP45 is accessible, the projector solar
cell leads can be moved from P1 to P2 in
order to try using the second optical preamp
circuit, however this input may not be set
up correctly so care will be needed with the
volume control.