HP 54520 Series Service Manual page 107

Chapter 6: Replacing Assemblies
To remove and replace the main assembly
To remove and replace the main assembly
Use the following procedure to remove and replace the main assembly. When necessary, refer
to other removal procedures.
ELECTROSTATIC DISCHARGE!
Use grounded wrist straps and mats when servicing the main assembly. Electrostatic
discharge can damage electronic components.
CAUTION
e If you are replacing the main assembly with an exchange assembly, you will have to move
the attenuators to the replacement assembly. Attenuators are not part of the main
assembly.
e If you are installing a new main assembly, the replacement assembly includes attenuators.
1 Disconnect the power cable.
2 Remove the cover.
3 Remove the following in order.
e Rear panel
e Disk drive
© Power supply
4 Disconnect the following cables from the main assembly.
e Disk drive cable
e Power supply cable
e Line sync cable
e Display cable
e Keyboard cable
Front panel probe compensation cable
Carefully place the instrument on its side.
From the bottom of the instrument, remove eight screws that secure the main
assembly to the cabinet.
7 Remove the nuts that hold the BNCs to the front panel.
8 Set the instrument in the normal position.
9 Slide the main assembly out of the cabinet to the rear.
10 Replace the main assembly by reversing this procedure.
an
If you permanently replace parts
If you have permanently changed any combination of main assembly, attenuator, or acquisition
hybrid, you will need to adjust the high-frequency pulse response on the affected channels. For
example:
Hf you permanently swap two attenuators or acquisition hybrids during troubleshooting, you
must adjust the channels affected.
If you replace one attenuator or hybrid, you must adjust that channel.
If you replace the main assembly, you must adjust all channels.