Agilent Technologies 1142A, Руководство пользователя

Страница: 18 / 34

18
1142A Probe Control and Power Module
Service
Local and Remote Control
The front panel switch controls the dc reject and offset functions. It
also selects remote operation, which allows control through the rear
panel remote input connector.
Power Supply
The power supply provides ±6V and ±15V for the probe and analog
control circuitry as well as +5V for the digital control circuitry.
Removing and Replacing
Assemblies
Use the following procedure to disassemble the probe control and
power module.
WARNING Hazardous voltages exist on the power supply. To avoid electrical shock,
adhere closely to the following procedures.
1
Remove the power cord.
2
Remove four flathead screws and remove the top cover.
WARNING Be sure to reconnect the safety ground when reassembling the
instrument.
3 Unplug the safety ground from the tab on the rear panel of
the instrument.
4 Note the orientation of the knobs. Remove the two knobs.
5 On the bottom of the instrument, remove the 5 mm screw
that fastens the transformer support.
6 Remove the following pan- head screws.
■
Three directly on the PC board.
■
Two on the ac input connector.
■
Two on the heat sink.
7 Remove the PC board. Slide it slightly forward so parts will
clear the rear panel, then lift the rear of the board out while
sliding it backwards.
8 Remove the two heat sink spacers from the standoffs that
were directly under the heat sink.
9 Reverse the procedure to reassemble the control and power
supply.