Owner`s manual

page 14 – 3
RD-12 / March 00
METERBRIDGE and CLOCK
A buffered output of the oscillator is available at pin #9 of IC #U22 to assist in
adjusting the oscillator. This testpoint “TP1” is right between the 14-pin ribbon
cable header and IC “U22” in the upper right corner of the main display PCB (as
you are looking at the card with the meterbridge hinged fully open).
Setting the Time
The setting controls consists of two switches: MODE and SET. To set the
clock, open the meterbridge and stand behind the console (this will enable you
to see the display):
1) The control switches (mounted inside the meterbridge bottom) are la-
belled "M" and "S". "M" (
Mode) is used to scroll from seconds to min-
utes to hours; "S" is used to
Set the time. The procedure is to set the clock
slightly ahead of the current time, hold the second count at "00" until the
current time catches up, and then release the count.
2) Press the MODE button until the hour digits blink. Depress the SET
button until the desired hour is displayed.
3) Press the MODE button until the minute digits blink. Depress the SET
button until the desired minute count is displayed.
4) Press the MODE button until the second digits blink. Depress and hold
the SET button; the seconds display will hold at "00" (blinking once per
second). When the current time catches up to the display, release the SET
button. The clock will start counting. Hit the MODE button one more
time to place the clock into working mode.
Battery Backup
With the meterbridge open, note the nickel-sized round battery socket at
the bottom of the clock display card. This will hold a Duracell DL2032/3V
long-life lithium battery (it goes into the socket negative side in). Note the
battery does NOT light up the clock display; it powers the clock crystal to keep
it from losing count (it will do this for 3 to 4 weeks).
Operational Modes
The standard factory default clock configuration is crystal-controlled, 12
hour mode, stand-alone operation. However, the clock will operate either
from the internal crystal controlled time base or from a 60 Hz power line
signal. It can also be programmed to count in either 12 hour or 24 hour modes,
and the internal counters can be slaved from another clock or other sources of
1 Hz timing signals (TTL levels). Contact factory technical support for further
information.