Mitsubishi Q2ACPU User Manual page 333

21. MAINTENANCE AND INSPECTION
Be sure to shut off all phases of the external power supply used by the system
WARNING
before cleaning or retightening the terminal screws or module mounting screws.
Failure to do so may result in an electric shock.
If they are too loose, it may cause a short circuit or malfunctions.
If too tight, it may cause damage to the screws and/or module, resulting in an
accidental drop of the module, short circuit or malfunctions.
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