Troubleshooting; Work Precautions - Mitsubishi Electric GUG-01SL-E Handbook

7. Troubleshooting

Work precautions

• Before starting the service, the power supply isolator must be turned off. Pay sufficient attention to avoid
electric shock or injury.
• When removing or touching the cables, circuit boards or other parts, make sure to turn off the power supply
isolator.
• Even after the power supply isolator is turned off, the capacitor on the circuit board retains high voltage for a
while. Therefore, before servicing, wait for at least five minutes, and then use a tester to check that the volt-
age has dropped.
• Terminals of a large electrolytic capacitor in the power circuit section continues to generate low-voltage for
approximately one hour after the power shutdown. Therefore, handle the circuit board very carefully when
replacing it.
• Once the power supply is turned off, be sure to wait for at least five minutes before turning the power back
on again.
• When servicing, be sure to reproduce the malfunction two or three times before starting repairs.
• When servicing, always take care to keep proper footing.
• When removing the circuit board, always hold it at both ends and remove carefully so as not to apply force
to the surface mounted parts.
• When removing the circuit board, be careful of the metal edges on the board.
• When removing or inserting the connectors for the circuit board, hold the entire housing section. Never pull
on the lead wires.
• If it is thought that there is a circuit board malfunction, check for disconnected wires in the print pattern,
burnt parts or discoloration.
• If the circuit board is replaced, make sure that the switch settings on the new board are the same as the old
board.
• Make sure to connect the power supply wires correctly.
The part names in the texts are standardized with the part names in the parts catalog. (There are some
exceptions.)
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