6-13 REMOVING AND
REPLACING THE FAN
ASSEMBLY
This paragraph provides instructions for removing and replacing the
fan assembly,which is located on the rear panel assembly (see Figure
6-4).
Preliminary Disconnect the power cord from the unit. Remove
the chassis covers as described in paragraph 6-2.
Remove the rear panel assembly as described in
paragraph 6-10.
WARNING
When power is removed from the instrument, always allow
five minutes for the capacitors on the A21 Line Filter/Recti-
fier PCB to discharge before removing the rear panel assem-
bly.
Procedure Remove and replace the fan assembly as follows:
Step 1 Withthe rear panel laying flat, use a
Phillips screwdriver to remove the four
screws and flat washers that fasten the
fan mount to the rear panel.
Step 2 Lift the fan mount, containing the fan as-
sembly,from the rear panel assembly.
Step 3 Remove the fan assembly from the fan
mount.
Step 4 Clean the honeycomb fan filter as re-
quired before replacing the fan assembly.
Step 5 Toreplace the fan assembly, reverse the
removal process.
NOTE
Toensure proper cooling of the unit,
always mount the fan assembly
with the airflow direction indicator
arrow on the fan body pointing to-
ward the interior of the instrument.

6-18 682XXB/683XXB MM

REMOVAL AND FAN

REPLACEMENT PROCEDURES ASSEMBLY