thanks for the replies!
my burner is a 5 string one, and yes, the end of serial number is DA5
about the neck diving, yes, i've used my forearm to balance the bass, but this is a little bit uncomfortable. ken, is there anything else i can do to deal with this? maybe changing the back strap button to another position?
anyway, if it can't be solved i don't care, i love it so much!