The monitor screen twists with wavy lines and the picture bends
Cause: This is caused by electromagnetic interference (EMI) from some other appliance such as a fan, motor, or even other monitors, either very close to the monitor or on the same power circuit.
Solution: Move the other appliance out of range of the monitor or off the same power circuit. If the symptom continues, there could be an EMI problem with the monitor itself. Have it checked at the repair shop.