Samsung WF906 Series Service Manual page 26

Part
Replacement of the
main PCB
Reassembly is in the reverse order of the removal.
24 _ Disassembly and Reassembly
Figure
4 Check Points for Troubleshooting
1. Check whether there is any error in applying the power.
2. Check the voltage between the DC 5V and GND terminals.
3. If an error occurs when there is no characteristic error in the electric harnesses, check
these points:
HE/HE1 error: The resistance of heater(for 1900W unit) is 27 Ω
DE1 error: The resistance of door switch is 140 to 145 Ω
HE/HE1 error: The resistance of thermostat is 0 Ω
4E error: The resistance of water valve is 4.4 kΩ
Description
1. Remove the back cover and unfasten the
screws that hold the main PCB in place
2. Remove the PCB cover inside.
Remove the wire harness connector which
is connected to the PCB.
3. Replace the main PCB.
You cannot remove the PCB separately
because urethane is used for water
proofing.