Simpson 36S550 Washer with possible light error code?

Hi,

I have a Simpson 36S550 top load washing machine. You can turn on Power button, select wash cycle, water level and temperature, but when you press start button the 3 LED lights in the water temperature light panel all flash together and beeps. Have replaced circuit board with a second hand one and have changed hot/cold water inlets around at back in case cold was faulty. No fix though. Any help would be appreciated.

Thanks.