You will want the service manual to tackle this. Link is below for electrotanya. The power supply board and circuit diagram are on page 44. The lower potion of the schematic is the relay circuit. I would start by checking Q930, the diodes and capacitors on that circuit board, but note that the circuit also connects to the main board so the repair may not be trivial if the problem is not isolated to the power board.
Electronics forum for electronics experts to repair defective appliance.
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