Neo Z83-4 Auto Power on not working.

My Z83-4 auto power-on does not work at all. I have updated BIOS to 1.8 and set to 'Always On'. Killing power whilst in OS and restoring has no impact. I'm sure it shouldn't matter, but i have rebuilt to Win 10 Pro. Bios settings otherwise as standard and seem to be retaining settings so not battery (i think). It is 1 year old, but has not been powered on for more than 24 hours during that time. Any suggestions?