Keysight 34401A, Руководство по обслуживанию

Страница: 81 / 165

To Unsecure the Multimeter Without the Security Code
To unsecure the meter without the correct security code, follow the steps
below. Chapter 9, “Schematics,” contains the schematics associated with
this procedure. See example 1 in chapter 3, “Menu Tutorial,” starting
on page 53, for an example of entering the security code. Also see
“Electrostatic Discharge (ESD) Precautions” on page 114 before
beginning this procedure.
1
Disconnect the power cord and disconnect all input connections
(both front and rear terminals).
2
Remove the instrument cover. There are two rear panel screws
and one screw on the bottom cover (see the mechanical
disassembly drawing on page 9-3).
3
Remove the internal metal shields, push the top shield to the
side, and then lift out (see the mechanical disassembly drawing
on page 9-3.)
4
Connect the power cord and turn on the multimeter.
Be careful
not to touch the power line connections.
5
Apply a short between the two exposed metal pads on
JM500
(located between
U500
and
U506
). The exposed metal pads are
outlined with a small rectangular silkscreen. (See the component
locator drawing for the 34401-66501 Main PC Board on page 9-5.)
6
While maintaining the short, enter any valid unsecure code.
The multimeter is now unsecured.
7
Remove the short at
JM500
.
8
Reassemble the multimeter.
Now you can enter a new security code. Be sure you take note of the
new security code.
Chapter 4 Calibration Procedures
Calibration Security Code
74