LG intellowasher 7kg would not power up?

My intellowasher 7kg stopped powering up after several times of doing the same thing in the past but after switching off the mains and back on it powered up and started washing. this time i did the same thing but still it wouldnt power up. it will always make a beep sound when i switch the mains off and then on but no lights are displayed even though it makes the usual beep after powering on. is it the motherboard that is gone and is it cost effective for reapirs? please advice.