TM 1-1520-238-T-5
8–31
8–7.
SYSTEM DESCRIPTION (cont)
8–7
SUN SHIELD
ELEMENT
SENSING
WALL
FUSELAGE
DIAL
POINTER
MOVEMENT
MECHANICAL
M68-136
Figure 8–26.
Pilot OAT Indicator Functional Block Diagram
(4) The clock (fig. 8–27) mainspring drives the clock mechanism which in turn drives the clock hands and
the elapsed time hand. To wind the main spring, the winding set knob is pushed in and turned. When winding, the
set knob is pulled out to set the hour and minute hands. The elapsed–time pushbutton control has three stages of
action. The first push resets the elapsed–time and second sweep hand to zero. The second push starts the
elapsed–time and second sweep hand to keep time. The third push stops the elapsed–time and second sweep
hand.
CLOCK
MECHANISM
MAINSPRING
AND MINUTES
HOURS
AND MINUTES
HOURS
AND SECONDS
ELAPSED-TIME
PUSHBUTTON CONTROL
30
15
45
60
1
2
3
4
5
6
7
8
9
10
12
11
0 - 5 VDC EDGE -
LIGHTING
PILOT EXT
LT/INTR LT
CPG INTR
LT PANELS
ELAPSED-TIME
M68-135
CLOCK
Figure 8–27.
Clock Functional Block Diagram
8–8.
MULTIPLEX READ CODES
8–8
Multiplex read codes are not applicable to instruments, but are applicable to HARS signal outputs which are sent
to the flight instruments.
