Hitachi FSG Series Service Manual page 86

1
TROUBLESHOOTING
78
Œ
Purpose
Symbol PCB
PCB1 for Control
PCB2 for Fan
PCB3 for Inverter
PCB5 for "SNUBBER"
a. Control Printed Circuit Board: PCB1
1. Transmitting between Indoor Unit and Outdoor Unit
2. Processing for Sensor Input
3. Processing for Dip Switch Input
4. Operation Control for Above items 1 to 3.
Compressor Operation Control, Bypass Valve Control, Fan Control and Overcurrent Control
5. 7-Segment Indication
6. Processing of Safety Device Input
7. Processing of Relay Output
8. Reverse Phase Detection for Power Source
Fan Speed Control
1. Inverter power part is driven by instruction of PCB1 and compressor is driven.
2. Overcurrent Control
3. Protection Control for Inverter Part
1. Restraining of Surge Voltage added to Transistor Module (IPM)
2. Absorbing for Switching Noise of Transistor Module (IPM)
Purpose