Anything that uses electricity to work contains a risk that if it is faulty then it could lead to an electric shock. There are certain devices that are considered more dangerous than others and users should be warned that trying to fix these would be best left to professional electronic engineers, e.g. a computer monitor should not be opened even after mains power has been switched off because a dangerous electrical charge remains.
Computers and their associated peripheral, such as printers, scanners are powered from the mains and as such are a potential hazard. Therefore, the risk of electric shocks applies to all users and not just technicians who have the systems opened while they are working with them.
Greater care must be exercised when a technician is working with an open system. It is advised that all of the equipment under repair or modification is disconnected from the mains supply during the entire process.
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