Electrical System Functional Test Procedure - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
5-91. ELECTRICAL SYSTEM FUNCTIONAL TEST PROCEDURE.
NOTE
Service personnel should refer to Figures 5-30 or 5-30a for
amplifier schematic and to Section Xl 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 UP and DOWN operation of wing
flaps.
e. If the wing flaps fail to operatel 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 volt leg of
the coils of relays K I 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 K I at pin 6 or relay K2 at pin 4 of the connector, then fabricate a jumper lead to extend
from pin I (A+) of the connector to either wire lead F4E of relay K I 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 Kl 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 con-
nector J 1.
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 approxi-
mately +4 volts in the up position.
o. If the RC voltage readings are too high or too low, the problem is either in the harness wiring or the
control box. Test the harness wiring, if defective repair or replace the harness wiring. If the harness wiring is
good replace the control box.
Revised: 3/31/94
SURFACE CONTROLS
1K8