Keysight 1143A, User'S And Service Manual

Page: 34 / 56

To disassemble the instrument
Use the following procedure to disassemble the 1143A Probe Offset Control
and Power Module.
W A R N I N G
Hazardous voltages exist on the power module. Failure to adhere closely to
the following procedures can cause electrical shock.
1
Remove the power cord.
2
Remove four flathead screws and remove the top cover.
W A R N I N G
Be sure to reconnect the safety ground when reassembling the instrument.
Failure to reconnect the safety ground can result in electrical shock.
3
Unplug the safety ground from the tab on the rear panel of the
instrument.
4
At the PC board, disconnect the cables that connect the front panel
probe power outputs.
5
Note the orientation of the knobs. Remove the four knobs.
6
On the bottom of the instrument, remove the 5 mm screw that fastens
the transformer support.
7
Remove the following pan-head screws.
•
Three directly on the PC board.
•
Two on the ac input connector.
•
Two on the heatsink.
8
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.
9
Remove the two heatsink spacers from the standoffs that were
directly under the hearsing.
10
Reverse the procedure to reassemble the power module.
Service
Troubleshooting and Repair
34