Piper Navajo PA-31 Service Manual page 255

PIPER NAVAJO SERVICE MANUAL
5-87. REMOVAL OF FLAP CONTROL AMPLIFIER.
a. Open access door in nose of airplane to gain access to amplifier at station 59.00
b. Disconnect the electrical plug from the amplifier.
c. Remove the attaching screws and remove the amplifier from the airplane.
5-88. INSTALLATION OF FLAP CONTROL AMPLIFIER.
a. Install control amplifier in airplane and secure with attaching screws.
b. Connect the electrical plug to the amplifier.
c. Check rigging and adjustment of flaps per instructions given in this section.
d. Close and secure access door.
5-89. ELECTRICAL SYSTEM FUNCTIONAL TEST PROCEDURE.
NOTE
The serviceman should refer to Figure 5-26a or 5-26b for amplifier
schematic and to Section XI for the schematic diagram of the system
when accomplishing this test procedure. To gain access to the system
components refer to the appropriate Removal and Installation
Instructions in this section of the manual.
a. Pull all circuit breakers to the OUT position.
b. Actuate the flap motor and flap control circuit breakers.
c.
Turn ON battery master switch or connect external power to aircraft.
d. Operate the flap selector handle in the control box and observe L Pand DOWN operation of wing
flaps.
e
If the wing flaps fail to operate, check fault light. If fault light is ON proceed to Step m. If fault light
is OFF proceed to Step f.
f. Check for 27.5 volts at motor contactor
and pin I of connector J I to verify circuit breakers and
wiring are not defective.
g. Check for 27.5 volts across power terminals of both K1 and K2 relays.
h. Disconnect the flex shaft(s) from the motor assembly.
i. If the drive motor fails to operate. check the UP and DOWN limits switches in the 27.5 olt leg of the
coils of relays K1 and K2. Do this by checking for 27.5 volts at the N.C. contacts on the limit switches.
j. To check the drive motor and relay operation disconnect the electrical harness plug connector E368.
Ground relay K1 at pin 6 or relay K2 at pin 4 of the connector. then fabricate a jumperlead
to extend from pin I
(A+) of the connector to either wire lead F4E of relay K1 or wire lead F4D of relay K2 to actuate either the up
or down relay and run the motor
k. Check the 27.5 volt power at the drive motors while another person is energizing relays K I and K2.
If 27.5 volts is not present at the drive motor, the contacts of relays K1 and or K2 are defective. Replace
defective relay(s). If the drive motor operates by energizing relays K1 and or K2 locally. the trouble is in the
control box. the left wing potentiometer
RL. the right wing potentiometer RR. or in the flap control amplifier
1.
Reconnect the flex shaft(s) to the motor assembly and connect the electrical harness plug to
connector J1.
m. Pull the flap motor circuit breaker to prevent the flap motor from running for the remainder of the
test procedure.
n. Using a precision voltmeter ( 10-volt range) connect the negative lead to the GND test jack of the
amplifier and the positive lead to the RC test jack. Slowly operate the flap selector handle in the control box
over its entire range. The voltage readings should be approximately
-9 volts in the down position and
approximately
+4 volts in the up position.
Revised: 10/12/83
SURFACE CONTROLS
Effectivity
CALCO
1K15