Fujitsu ASU9RLQ Service Instructions Manual page 51

Serial Signal Receiving Error
[Check Point]
Check which has a cause of error, either Indoor unit or Outdoor unit.
* Remove indoor unit front panel and cable xlampers and keep the terminal block clear so that it can be
measured with a meter.
* Remove AC power and reset the power, and press Test Operation switch on remote control.
[Check Procedure]
CAUTION: Keep out hands from terminal base and electrical components. Voltage is
applied on them and you may get electric shock.
[Indoor Unit Check]
Does indoor unit start to operate?
Does voltage AC208 to 230V appear between NO
terminal 1 and 2 of indoor unit terminal base?
Measure voltage between terminal 2 and 3 of
indoor unit terminal base. Is it normal?
Indoor unit control unit is normal.
Check outdoor unit control unit.
[Outdoor Unit Check]
Does voltage AC208 to 230V appear between
terminai 4 and 5 of outdoor unit terminal base?
Does voltage AC208 to 230V appear at NO
DC voltage terminal?
Outdoor unit controller PCB board failure.
YES
YES
YES
YES
YES
YES
NO
Conduct the inspection on "no operation at all".
NO
Check cable wiring of terminal base.
Check cable wiring of terminal base of indoor
and outdoor unit correctly connected as numbered.
NO
Indoor unit controller PCB IC10 failure.
NO
Check power supply connection.
NO
Check broken fuse, wiring connection.
07-07