Keysight Technologies N5290/1A PNA Series Service Manual page 16

Safety and Regulatory Information
General Safety Considerations
There are no replaceable fuses in the mains input or within the power
supply assembly.
Keysight personnel: after calibration is completed, attach four "calibration
void if seal broken" stickers to the PNA as shown in
Figure 1-1 Example of a Calibration Sticker on a PNA
1-6
Figure 1-1.
Keysight N5290/1A Service Guide