6-4 REMOVING AND
REPLACING THE A3, A4,
A5, OR A6 PCB
This paragraph provides instructions for removing and replacing the
A3 Reference Loop PCB, the A4 Coarse Loop PCB, the A5 Fine Loop
PCB, or the A6 Pulse Generator PCB, all of which are located in the
RF housing (see Figure 6-3).
Preliminary Disconnect the power cord from the unit and remove
the top cover as described in paragraph 6-2.
Procedure Remove and replace the A3, A4, A5, or A6 PCB as
follows:
Step 1 Disconnect the coaxial cables from the
PCB to be removed by lifting up on the
cable connectors.
Step 2 Using a Phillips screwdriver,remove the
nine screws that retain the RF housing
cover and set aside.
Step 3 Remove the RF housing cover and set
aside.
Step 4 Lift up on the edge tabs of the PCB and
lift it out of the RF housing.
Step 5 Remove the “O” rings installed on each
MCX connector and retain them for use
on the replacement PCB.
Step 6 Toreplace the PCB, reverse the removal
process.

6-8 682XXB/683XXB MM

REMOVAL AND A3, A4, A5,

REPLACEMENT PROCEDURES OR A6 PCB