Check Of Indoor Unit Control Board; Display Board And Remote Control Check Of Indoor Unit - Samsung SH09BWHA Service Manual

Troubleshooting
6-3-1 (A) Check of indoor unit control board
√ Unplug the power cord and plug it after 5 seconds.
√ Press the on/off switch located indoor unit inside to operate the air conditioner.
• If the air conditioner operates, check the remote control and indoor unit display board.
• If the air conditioner does not operates, check according to the sequence of the followings:
√ Check sequence of indoor unit control board
Step 1 : Check whether two wires of power cord (Sky-blue, brown) are connected correctly to the terminal block and
Relay on the control board.
Step 1 : • Sky -blue : connected to "N(1)" of Terminal block
Step 1 : • Brown : connected to RY71 Tab terminal (control board outer side)
Step 2 : Check whether the wire connected to the terminal block is connected to th control board.
(Control board)
CN71
RY71
CN71
Step 3 : Check whether the fuse (F701) on the control board is normal. (3.15[A]/250[V]:F701)
Step 1 : • If the fuse is broken, replace it with new one.
Step 4 : Check the output voltage of SMPS on the control board.
Step 1 : • Input power AC178 ~ AC 264V— • CN22 1-3pin : DC12V
Step 1 : - Input power AC178 ~ AC 264V— •
Step 1 : - CN22 : As socket not mounted measure at the solder points
Step 5 : Check whether the control board gets wet with dew
Step 1 : • Dry the control board.
Step 6 : Check whether tiny metal objects make a short circuit on the PCB, especially between pins of the surface mount IC.
Step 1 : • remove the objects. Do not use splay solvent or some components may get damage by solvent.
6-3-2 (B)(C) Display board and remote control check of indoor unit
√ Check whether the connection wire of Display board is correctly connected to CN91 connector.
√ Check the voltage of remote control battery. - the voltage of one battery shall be higher than about 1.4V, and then the
remote control operates normally.
√ Check whether the neon sign is on and the 3 wave long fluorescent lamp is on around the indoor unit. - After putting all lamps of
the indoor out and then operate it by remote control. If it operates with the remote control, it is the abnormality due to the
interference from the light of lamps. (Aircon unit is normal).
6-3-3 (D) Check the indoor temperature sensor and indoor heat exchanger temperature sensor.
Take out the thermistor connected to the connector (CN43) of control board of indoor unit and measure the resistance between
two wires and if it is same as follows: it is normal but if not, replace it.
Ambient temperature
(°C)
Resistance of
thermistor [KΩ]
22
(Terminal block)
SKY-BLU
N(1)
BRN
1
BLK
2
CN22 2-3pin : DC5V
15°C 20°C 25°C
14.68 12.09
30°C 35°C
10 8.31 6.94
40°C
5.83
Samsung Electronics