By hvhipot 
Maintenance of digital megohmmeter:
1. The megohmmeter must be placed flat when in use.
2. Keep away from large external current conductors and external magnetic fields.
3. The megohmmeter should be placed in a dry and ventilated place.
4. The greater the insulation resistance of electrical equipment, the better.
5. The insulation resistance of the motor or circuit is reduced, short-circuited, and need to be repaired and cannot be used.
6. When the measured object is a normally charged object, the power supply must be turned on first, and then the measurement.
7. The surface of the measured object should be clean to reduce the contact resistance to ensure the correctness of the measurement result.
8. For equipment that may induce high voltage, this possibility must be eliminated before measurement can be performed.
9. After use, the dry battery in the instrument should be taken out to prevent the electrolyte from overflowing and damaging the instrument.
10. When the meter is not used for a long time, the rechargeable battery pack should be charged and maintained regularly.