Keysight Technologies N5261A User's And Service Manual page 94

Service Information
To prevent electrical shock, disconnect the Keysight N5261A or
N5262A from mains electrical supply before cleaning. Use a dry cloth
or one slightly dampened with water to clean the external case parts.
Do not attempt to clean internally.
If flammable cleaning materials are used, the material shall not be
stored, or left open in the area of the equipment. Adequate ventilation
shall be assured to prevent the combustion of fumes, or vapors.
Keysight N5261/62A User's & Service Guide
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