Keysight Technologies Option 503 Service Manual page 24

Overview
Before You Start Troubleshooting
Always use the three-prong ac power cord supplied with this product.
Failure to ensure adequate earth grounding by not using this cord may
cause product damage.
This instrument has an autoranging line voltage input; be sure the supply
voltage is within the specified range.
24 N9030A PXA Signal Analyzer Service Guide