Owner`s manual

page 14 – 2
RD-12 / March 00
METERBRIDGE and CLOCK
Meterbridge and Clock
Overview
The console’s meterbridge houses three pairs of left-right LED meters
(Program, Audition, and Utility; see “Meter Output Module” Chapter 7), the
digital timer display (timer control buttons are on the MOD-5 Meter Output
Module; see page 7-2), left and right cue speakers (controlled by the CRD-5
Control Room Module; see page 5-2), and the console clock (next section).
Each LED meter pair is switchable to either VU or PPM (peak Program Meter)
modes. The slide switch for each pair is located on the rear of face of the LED
meter PC board.
The meterbridge assembly hinges open for easy access setting the clock.
Simply remove the three black #4 flathead screws along the bottom lip of the
meterbridge, just above the tops of the console modules and swing the bridge
up and back until it rests in a fully opened position.
Replacement Parts
Clock, timer and VU meters cards and replacement cue speakers are
available. See Appendix for specific ordering information.
Console Clock
The Wheatstone digital clock is a six-digit time-of-day clock with LED
display. The clock is designed with CMOS circuits and an on-board crystal-
controlled time base oscillator. There are two basic parts to the clock: a main
PCB containing the clock displays and circuits (including battery backup),
and a remote switch card containing controls for setting the clock. The remote
switch card is mounted in the bottom of the console meterbridge; it may be
accessed by opening the hinged meterbridge (see above).
Controls
The clock is controlled by a trimmer and two switches; the trimmer is
mounted on the main clock PCB assembly and the switches are mounted on
the control card.
The trimmer alters the frequency of the quartz-controlled oscillator,
which in turn causes the clock to run slightly slower or faster. In order to keep
accurate time, the oscillator must run at 32.768 KHz, which is divided down
internally to yield 1.000000 Hz at the input of the counter. The oscillator is set
to this frequency at the factory. However, due to the nature of quartz/crystal-
controlled oscillators, there may be a slight change in the frequency of the
oscillator during the first few months of operation due to the aging effect of
quartz crystals. A minor readjustment of the trimmer will compensate for this
effect.