6-3 REMOVING AND
REPLACING THE FRONT
PANELASSEMBLY
This paragraph provides instructions for removing and replacing the
front panel assembly of the 682XXB/683XXB. The front panel assem-
bly contains the A1 and A2 Front Panel PCBs. Refer to Figure 6-2 dur-
ing this procedure.
Preliminary Disconnect the power cord from the unit and remove
the chassis covers as described in paragraph 6-2.
Procedure Remove and replace the front panel assembly as fol-
lows:
Step 1 Using a Phillips screwdriver,remove the
screws and the front handle assemblies
from the instrument. (For instruments
not having front handles, remove the
screws and the front top and bottom feet
from the instrument.)
Step 2 Remove the rotary knob from the front
panel by pulling straight out on it.
Step 3 Carefully pull the front panel away from
the chassis until the screws attaching the
front panel assembly to the chassis are
accessable.
Step 4 Remove the screws attaching the front
panel assembly to the chassis sides.
Step 5 Disconnect the front panel ribbon cables
from connectors J1 and J22 of the Moth-
erboard.
Step 6 Turnthe instrument upside down.
Step 7 Remove the screw attaching the front
panel assembly to the chassis pan.
Step 8 Carefully pull the front panel assembly
forward until it is clear of the RF OUT-
PUT connector.
Step 9 Disconnect the coaxial cables, W119and
W120, from the front panel assembly con-
nectors A2J14 and A2J13 by pulling
straight out on the cable connectors.
Step 10 Toreplace the front panel assembly, re-
verse the removal process.

6-6 682XXB/683XXB MM

REMOVAL AND FRONT PANEL

REPLACEMENT PROCEDURES ASSEMBLY
NOTE
The screws with green heads have
metric threads. When it becomes
necessary to replace any of these
screws, always use the exact re-
placement green-headed screws
(ANRITSU P/N 2000-560) to avoid
damage to the instrument.