Power Supply Abnormalities Or Faulty Indoor Printed Circuit Boards - Daikin FTK25JVE9 Service Manual

Trouble shooting
5.7 Power Supply Abnormalities or Faulty Indoor Printed
Circuit Boards
∗
Remote
Controller
Display
Indoor unit LED
Display
Method of 1. The proper program operation of the microcomputer is checked by the program.
2. In indoor-outdoor signal communications, the indoor unit determines whether the outdoor
Malfunction
Detection
Malfunction 1. When the microcomputer program does not function properly.
2. When the indoor unit determines that the indoor unit does not properly receive signals
Decision
Conditions
"
Supposed
"
Causes
"
"
Troubleshooting
72
U4 U4 U4 U4
or
unit receives signals properly by detecting signals transmitted by the outdoor unit to the
indoor unit.
transmitted by the outdoor unit in indoor-outdoor signal communications.
Display disabled by fault power supply.
Faulty signal transmitting/receiving circuit in indoor printed circuit boards (1) and (2)
Microcomputer program is in abnormal condition due to an external factor.
• Noise.
• Momentary voltage drop.
• Momentary power failure, etc.
Faulty indoor unit PCBs (1) and (2).
Be sure to turn off power switch before connect or disconnect connector,
Caution or parts damage may be occurred.
Check voltage of AC power supply.
220 ~ 240V ±10%
Does the
power supply have the rated
voltage?
YES
Check the varistor of the indoor
unit PCB.
Is it damaged?
NO
Check the fuse of the indoor unit
PCB.
Is there conductivity?
YES
NO
YES
NO
Si04-115
Check the power supply, and
correct it if not proper.
Replace the varistor.
Replace the fuse.
Replace indoor PCB (1).
(R1949)
Service Diagnosis