Keysight Technologies 3458A Guide D'utilisation page 428

C Procedure to Lock Out Front/Rear Terminals and Guard Terminal Switches
Figure C-7
3 Refer to
4 Refer to
428
3458A inside top view
Figure C-8. Locate the pushrod for the Front/Rear Terminal switch.
Pull the pushrod off. You may need to pry the pushrod loose with a small flat
blade screwdriver, Set the switch in the position it is to be used.
Figure C-7. Replace the top shield. Line up the slots on the shield with
the shield retainers. Then push the shield toward the front of the instrument
until the shield screw hole lines up with the hole in the chassis. Use the #TX 10
Torx driver to reinstall the shield screw.
Keysight 3458A User's Guide