b. Check for malfunction in interconnecting cables.
1. Ascertain Pins 1 and 3 of interconnecting cable are not reversed.
2. Using an ohmmeter, check continuity between Pin 1 and 3 of interconnecting cable. If a reading is
obtained on the meter, the cable is shorted and should be replaced.
—NOTE—
A short of the type described in steps 1 and 2 will not cause permanent
damage to the power supply, but the system will be inoperative if such a
short exists. Avoid any connection between Pins 1 and 3 of the
interconnecting cable as this will discharge the condenser in the power
supply and destroy the trigger circuits.
—CAUTION—
When disconnecting the power supply, allow five minutes of bleed
down time prior to handling the unit.
c. Check interconnecting cables for shorts.
1. Disconnect the output cables from the power supply outlets.
2. The following continuity checks can be made with an ohmmeter.
(a). Check for continuity between the connectors of each interconnecting cable by checking from Pin 1 to
Pin 1, Pin 2 to Pin 2, and Pin 3 to Pin 3. When making these checks if no continuity exists, the cable is broken
and should be replaced.
(b). Check continuity between Pins I and 2, 1 and 3, 2 and 3 of the interconnecting cable. If continuity
exists between any of these connections, the cable is shorted and should be replaced.
d. Check the tube socket assembly for shorts.
1. Disconnect the tube socket assembly of the anti-collision light from the interconnecting cable.
2. The following continuity checks can be made with an ohmmeter.
(a). Check for continuity between Pin 1 of AMP connector to Pin 1 of tube socket, Pin 2 of AMP
connector to Pins 6 and 7 of tube socket and Pin 3 of AMP connector to Pin 4 of tube socket. When making these
tests, if no continuity exists, the tube socket assembly is broken and should be replaced.
11-74. INSTRUMENT AND PANEL LIGHTS. The instrument and panel lights are broken up into two groups;
Upper panel and Lower panel. The instrument lights are controlled by a 5 amp circuit breaker through a switch to
a transistorized dimmer control unit located in the middle of the instrument panel. There are two control knobs
the one on the right is for radio light dimming and the one on the left is for panel light dimming. To gain access
to the dimmer control assembly follow the instructions below.
11-75. REMOVAL OF DIMMER CONTROL ASSEMBLY.
a. From behind the instrument panel remove the electrical plug from the dimmer control assembly.
b. From behind the instrument panel remove the two machine screws securing the dimmer control assembly
to the instrument panel there is one on top and one on the bottom of the assembly.
c. Dimmer control assembly can now be removed.
11-76. INSTALLATION OF DIMMER CONTROL ASSEMBLY.
a. Position the assembly into place.
b. Insert and secure with the machine screws previously removed.
c. Reconnect the electrical plug.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
ELECTRICAL SYSTEM
2E2
