Piper PA-28-161, Maintenance Manual

Page: 548 / 1104

PIPER AIRCRAFT, INC.
PA-28-161, WARRIOR III
MAINTENANCE MANUAL
PAGE 6
Nov 30/06
3F20
33-40-00
D. Troubleshooting Strobe Lights
When troubleshooting the strobe light system, it must first be determined if the trouble is in the flash
tube or the power supply. Replacement of the flash tube will confirm if the tube is defective. A
normally operating power supply will emit an audible tone of 1 to 1.5 KHZ. If there is no sound
emitted, check the system according to the following instructions. When troubleshooting the system,
utilize the appropriate schematic at the back of this section.
CAUTION: WHEN DISCONNECTING POWER SUPPLY, ALLOW FIVE MINUTES OF BLEED
DOWN TIME BEFORE HANDLING UNIT.
(1) Check that the input voltage at the power supply is 28 volts.
CAUTION: WHEN DISCONNECTING AND CONNECTING THE POWER SUPPLY INPUT
CONNECTIONS, DO NOT GET THE CONNECTIONS REVERSED. REVERSED
POLARITY OF THE INPUT VOLTAGE FOR JUST AN INSTANT WILL
PERMANENTLY DAMAGE THE POWER SUPPLY. THE REVERSED POLARITY
DESTROYS A PROTECTIVE DIODE IN THE POWER SUPPLY, CAUSING SELF-
DESTRUCTION FROM OVERHEATING OF THE POWER SUPPLY. THIS
DAMAGE IS SOMETIMES NOT IMMEDIATELY APPARENT, BUT WILL CAUSE
FAILURE OF THE SYSTEM IN TIME.
(2) Check for malfunction in interconnecting cables.
(a) Check that Pins 1 and 3 of interconnecting cable are not reversed.
(b) 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.
(3) Check interconnecting cables for shorts.
(a) Disconnect the output cables from the power supply outlets.
(b) The following continuity checks in Steps 3 and 4 can be made with an ohmmeter.
(c) 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.
(d) Check continuity between Pins 1 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.
(4) Check the tube socket assembly for shorts.
(a) Disconnect the tube socket assembly of the anti-collision light from the interconnecting
cable.
(b) The following continuity checks can be made with an ohmmeter.
(c) 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.