Message Name:

LIGHTNING SENSOR SYSTEM AMBER LX/F AND FAULT CODE DISPLAYED

On the Multi-Function Display (MFD), the Lightning Sensor System (LSS) symbols cancel and the amber LX/F legend and related fault code(s) show in the status window.

• Lightning Sensor Processor (A224)
• Lightning Sensor System (LSS) Antenna (E55)
• Audio Control Panel 1 (A8)
• Audio Control Panel 2 (A9)
• Audio Control Panel 3 (A215)
• Lightning Sensor System (LSS) Relay (K1)
• Associated Wiring

Advisory Wire/Service Bulletin:

• SB700-23-002 - Modification - Third Very High Frequency (VHF 3) Communication System - Installation
• SB700-34-003 - Modification - Lightning Sensor System (LSS) - Installation

Forum Articles/Infoservice/Newsletter: None

1. Check if one of the fault codes that follow is displayed:

   Name of Display Unit	LX Fault Code	Fault Description (Not Shown on MFD)
   MFD	LX01	Power supply out of tolerance
   MFD	LX04	Data processor RAM fault
   MFD	LX05	Data processor checksum fault
   MFD	LX06	Data processor shared RAM fault
   MFD	LX09	I/O processor RAM fault
   MFD	LX0A	I/O processor checksum fault
   MFD	LX0B	I/O processor shared RAM fault

   1. If one of the fault code is displayed, go to step 6.
   2. If none of the fault code is displayed, continue with next step.

2. Check if one of the fault codes that follow is displayed:

   Name of Display Unit	LX Fault Code	Fault Description (Not Shown on MFD)
   MFD	LX0C	Nose magnetic field (Hn) out of range
   MFD	LX0D	Wing magnetic field (Hw) out of range
   MFD	LX0F	Low-frequency nose magnetic field (Hnlf) out of range
   MFD	LX10	Low-frequency wing magnetic field (Hwlf) out of range
   MFD	LX11	E-field low-frequency (Elf) out of range

   1. If one of the fault codes is displayed, check that the calibration switches (S1, S2, S3, S4) are set correctly and do close out.
      NOTE: The calibration switches and instruction label are on the front panel of the LSS processor. See the label to find the correct switch positions.
   2. If the fault codes are not displayed, continue with next step.

3. Check if the fault code that follows is displayed:

   Name of Display Unit	LX Fault Code	Fault Description (Not Shown on MFD)
   MFD	LX12	No data from antenna

   1. If the fault code is not displayed, do close out.
   2. If the fault code is displayed, continue with next step.

4. Disconnect E55P1 from the LSS antenna (E55). Perform a continuity check for open circuits between the LSS PROCESSOR connector (A224BP1) and LSS ANTENNA connector (E55P1) as follows:
   For the LSS processor (A224):

   From	To	Result
   A224BP1-6	E55P1-11
   A224BP1-7	E55P1-12
   A224BP1-10	E55P1-1
   A224BP1-11	E55P1-14
   A224BP1-14	E55P1-3
   A224BP1-15	E55P1-4
   A224BP1-18	E55P1-8
   A224BP1-19	E55P1-9
   A224BP1-13	E55P1-15
   A224BP1-22	E55P1-5
   A224BP1-23	E55P1-6
   Ground	Shield

   1. If there is no continuity, repair or replace the defective wiring as required. Connect E55P1 to the LSS antenna (E55).
   2. If there is continuity, continue with next step.

5. Check if there is a short-circuit between the pins of the LSS PROCESSOR connector (A224BP1) and Aircraft Ground as follows:
   For the LSS processor (A224):

   From	To	Result
   A224BP1-6	Ground
   A224BP1-7	Ground
   A224BP1-10	Ground
   A224BP1-11	Ground
   A224BP1-14	Ground
   A224BP1-15	Ground
   A224BP1-18	Ground
   A224BP1-19	Ground
   A224BP1-13	Ground
   A224BP1-22	Ground
   A224BP1-23	Ground

   1. If there is a short circuit, repair or replace the defective wiring as required and do close out.
   2. If there is no short circuit, continue with next step.

6. Replace the LSS processor. Is the fault still present?

   1. If NO, do close out.
   2. If YES, continue with next step.

7. Replace LSS antenna.
8. Do close out.