Safety and Preparation

De-energize the system using the circuit breaker.
Remove the top cover of the LHA.

Removal of the Old Board

Disconnect all harnesses from the Control and Tilt Board.
Remove the long hex standoffs.
Lift the board gently off of the threaded studs, working gently around the edges on the board as needed.

Installation of the New Board

Set all three banks (SW1, SW2, and SW3) of switches on the new board to match those of the board being replaced.
Set the new board on the threaded studs.
Gently press the board down onto the studs working in circular patterns from the center outward.
Return the hex standoffs to the threaded studs, snugging by hand in a circular pattern starting from the center of the board.
Re-attach all harness connections.

Post-Installation Verification and Calibration

Energize the system using the circuit breaker in the PDU.
Place the unit into Test Mode 2 (SW1-8 OFF, SW2-8 ON).
Confirm all LEDs are illuminated by holding a sheet of paper in front of the LHA at a distance where the pattern on LEDs can be easily recognized.
Press the SET button until the display reads CAL. The unit will cycle through each intensity (100%, 20%, 5%) and after the process has been completed, the display will resume indication of the glide slope.
If system does not indicate correct glide slope, system will need to have the Tilt/Glide Slope set. See page 21 for procedure starting with "Press GLIDE button".
Return the unit to Normal Operating Mode (SW1-8 OFF, SW2-8 OFF).
Replace the top cover.

Airport Lighting Company | L-880(L), L-881(L) Precision Approach Path Indicator Lights (PAPI)