Agilent Technologies 53147A Assembly Level Service Manual page 100

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WARNING
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CAUTION
Chapter 3 Replacing Assemblies
Removing the Rear Panel Assembly
Disconnect the external-reference input/output cable (coaxial) from
connector J8 on the main board. J8 is directly under the back edge of the
power supply near the chassis wall.
A two-wire AC-input cable (brown and blue wires) runs between the
AC input module on the rear-panel assembly and the connector that is
accessible through the cutout in the front of the power supply enclosure
(TB1). Disconnect this cable from the power supply.
If the Battery Option is installed, there is a two-wire cable (brown and
white wires) that runs between the AC input module on the rear panel
assembly and connector J3 on the Battery Option circuit board (J3 is the
third connector from the back edge of the board). Disconnect this cable
from J3 on the Battery Option circuit board.
Use a 5/16-inch nut driver to remove the self-locking hex nut that attaches
the rear panel assembly grounding wire (green/yellow) to the right wall of
the chassis. Slide the grounding lug off the welded stud on the chassis
wall, and thread the lock nut back onto the stud a few turns until it is
finger-tight.
Use a 7 mm nut driver to remove the two hex standoff screws that attach
the GPIB connector to the rear panel assembly.
AN ELECTRICAL SHOCK HAZARD EXISTS IF THE COUNTER IS
OPERATED WITH THE REAR PANEL ASSEMBLY GROUNDING
WIRE NOT PROPERLY CONNECTED TO THE CHASSIS. TO
PREVENT SERIOUS INJURY AND/OR DAMAGE TO THE
EQUIPMENT, NEVER OPERATE THE COUNTER UNLESS THIS
GROUND WIRE IS SECURELY CONNECTED TO THE CHASSIS
WALL AND THE REAR PANEL ASSEMBLY.
Carefully pull the rear panel assembly away from the back end of the
chassis. Guide the cables that remain attached to the rear panel assembly
as you remove it to prevent them from catching on other cables or other
components of the Counter.
When reinstalling the rear panel assembly, position it carefully to avoid
damage to the Battery Charging LED, the serial-port connector (RJ-12),
the GPIB connector, and the main board. If these components are not
correctly aligned with the openings in the back panel, they may be
damaged.
3-12 Assembly Level Service Guide