Finally I find the real problem…Thank you for everyone help!!!
I have fixed three boards, so I think 99% chance I get this bug.
It is very late day, I will public it tomorrow afternoon. Keep that as a secret for couple hours. 😀
And tomorrow daylight I need to contact the factory first, ask if they can fix the 300 pcs for me. If not, that will be a little trick for new hand of iron/hot air gun.
This indiegogo campaign makes me carries too much…For 2K more contributors, I can not afford any mistake. After this I will/must have a big rest. 😀 😀 😀