Aqualtis F01 error/fault?

hi, i have a hotpoint aqualtis 'aq9d69s' and the other day it stopped through a cycle with all lights flashing and an 'F01' error code. I took the control pcb out and found a burnt out transistor ( q29) when I say burnt out, I mean burnt out with a hole in it. Now, while, I am quite comfortable with changing the transistor, when I find out what number it is, i wonder, what could of caused this? and, if I change said transistor will it happen again?