CLOCK OPERATION
Normal Operation
The SEL button selects what is to be displayed
on the four digit window and the CTL button
controls what is being displayed. Pressing
select sequentially selects GMT, Local Time,
Elapsed Time and back to GMT. The control
button starts and resets Elapsed Time when
momentarily pushed. Normal operation of the
880A cannot accidentally reset time.
Setting GMT
Select GMT for display in the four digit
window with the SEL button. Simultaneously
press both the select and control buttons to
enter the set mode. The tens of hours digit will
start flashing. The control button has full
control of the flashing digit and each button
push increments the digit. Once the tens of
hours is set, the select button selects the next
digit to be set. After the last digit has been
selected and set with the control button, a
final push of the select button exits the mode.
The lighted annunciator will resume its
normal flashing, indicating the GMT clock is
running.
Setting LT
Select Local Time, LT, using the SEL button.
Simultaneously push the SEL and CTL buttons
to enter set mode. The tens of hours digit will
start flashing. The set operation is the same as
for GMT, except that minutes are already
synchronized with the GMT clock and cannot
be set in Local Time.
Control/Select Disable
When there is no aircraft power applied to the
clock the SEL and CTL buttons are disabled.
Elapsed Time Count Up
Select ET for display. Pressing the CTL button
will start ET counting. Elapsed Time counts up
to 59 minutes, 59 seconds, and then switches
to hours and minutes. It continues counting
up to 99 hours and 59 minutes. Pressing the
CTL button again resets ET to zero.
Elapsed Time Count Down
Select ET for display and enter set mode by
pressing both buttons simultaneously. A
count down from any time, a maximum 59
minutes and 59 seconds, can be set. The time
is entered the same as UT setting. Once the
last digit is set, pressing the SEL button exits
the set mode and the clock is ready to start
the countdown. Pressing the CTL button now
will start the countdown. The alarm becomes
active at zero, flashes the displys, and enables
the external alarm. Pressing either button, SEL
or CTL, will reset the alarm. After reaching zero
the ET counter will count up.
Test Mode
Hold the SEL button down for three seconds
and the display will indicate 88:88 and
activate all four annunciators.
M880A DIGITAL CLOCK
Elapsed Time
Local Time
GMT Time
