DDJ SX2 not powering on intermittently

Hi, I have a DDJ SX2 and having a problem whereby the unit intermittently won't power up. I used it today for the first time in a good few months and it turned on first time no problem, I used it for a while with no issues but after powering down it didn't turn on when I tried it a few minutes later and multiple attempts. After another few hours I tried it and it turned on again. Then again next time after that it wouldn't power up. I also found that if I turn on the power button and leave it for a while maybe an hour it will turn on eventually. I have a replacement power supply as I thought that may be the problem but same thing happens. Any ideas? Thanks