Hitachi mini-HNRQ1 Series Service Manual page 120

(3) Checking Method for Fan Motor Driver Board
● Detail of Check Points
CAUTION
!
● Check whether the high voltage still exists in the fan motor driver board after power is disconnected. When
the unit is operated, LED7 is turned ON. At the time of powering off the unit, LED7 is turned OFF. In this case,
the residual voltage is less than DC50V.
● If LED7 is turned ON while powering off the unit, please wait for about ten minutes, LED7 will turn OFF.
● IPM Circuit of Fan Motor Driver Board (In case of using Digital Tester)
Rectifier and Inverter Circuit of Fan Motor Driver Board. Remove all the terminals of the fan motor driver
board before check. If all the items (below table) are performed and all items are satisfied, the fan motor driver
board is non-defective.
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TROUBLESHOOTING