I decided a short while ago to string my Yamaha TRBX 504 with Rotosound Tru-Bass 88 strings to give it a nice, different range of sounds to my P and J. I found time to put them on today but as soon as I tightened the E string it broke the end off the nut! See pics below. So I'm gutted and rather annoyed. Surely this is a manufacturing defect in the nut? Reckon I'll have any joy getting Yamaha to replace the nut or should I just fork our for a new (possibly brass) one myself?