Message Name:

WING STROBE LIGHTS UNSERVICEABLE

Wing Strobe Light or Lights do not operate correctly.

• Wing Strobe Light Tube
• Right Wing Strobe Light (DS66)
• Left Wing Strobe Light (DS67)
• Right Wing Strobe Power Supply (A142)
• Left Wing Strobe Power Supply (A141)
• Strobe Light Switch
• External Lights Control Panel (AP11)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

WARNING: Do not disconnect the power supplies and/or the strobe lights for a minimum of two minutes after operation. The power supplies contain voltages that can kill.

WARNING: Set the strobe switch to the off position before you disconnect the connectors. The measurements with the power applied to the wing-strobe power-supplies must be done very carefully. There is 400 VDC applied to the connectors during this operation. The high voltage can cause death or injury to personnel and/or damage to equipment.

1. Set the STROBE switch to ON and check if all the wing/tail strobe lights operate.

   1. If all the wing/tail strobe lights do not operate, replace the EXTERNAL LIGHTS Control Panel and do close out.
   2. If all the wing/tail strobe lights operate, continue with next step.

2. Perform a voltage check between wing strobe light power supply connector to the nearest paint free point on the aircraft structure as follows:

   From	To	Expected Result	Result
   A141P1-A	nearest paint free point	28 VDC
   A142P1-A	nearest paint free point	28 VDC

   1. If there is 28 VDC, go to step 4.
   2. If there is no 28 VDC, continue with next step.

3. Investigate wiring and/or power source (SPDA 3).

   1. If fault remains, repair or replace as required and do close out.
   2. If system checks are good, continue with next step.

4. Measure the voltage at the connectors A141P2 for the left wing strobe light, on the power supply unit A141 and A142P2 for the right wing strobe light, on the power supply unit A142 as follows:

   From	To	Expected Result	Result
   A141P2-A	A141P2-D	400 VAC anode voltage
   A141P2-B	A141P2-D	400 VAC 1 ±0.08 HZ cathode pulse
   A142P2-A	A142P2-D	400 VAC anode voltage
   A142P2-B	A142P2-D	400 VAC 1 ±0.08 HZ cathode pulse

   1. If there is voltage, go to step 7.
   2. If there is no voltage, continue with next step.

5. Replace the defective Wing Strobe light tube.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

6. Replace the wing strobe light assembly.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

7. Check if the wing strobe light power-supply unit is serviceable.

   1. If it is serviceable, repair or replace the defective wiring of the power supply and do close out.
   2. If it is not serviceable, continue with next step.

8. Replace defective power supply.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

9. Perform wiring check for external lights control panel.

   1. If wiring checks are not good, repair defective wiring as required and do close out.
   2. If wiring checks are good, continue with next step.

10. Perform the troubleshooting for the CAS Message that follows:
    Selcet CAS MessageELEC SYS FAILELEC SYS FAULT
11. Do close out.