14 days, but I don't think it's "No question asked" 😬 There WILL likely be questions.it has never been shut down, though, never gone past the select language page as happens when you very first time open the screen on brand new mac
l bought it less than 2 weeks ago, heard that Apple in US take back no questions asked? wonder if hong kong does this too?
If you can get AC+ without having to run a diagnostic, that would be the best thing to do. Otherwise, you're likely stuck with a VERY expensive repair bill.