please help or advice

[painner]

Hi please can someone help or advice. I am trying to repair a fault on a power board on a bowers & Wilkins zeppelin iPhone docking station for my daughter. I have renewed the two blown capacitors but now have found a blown 3 legged surface mount device. There are a few good ones near the blown ( like the one in the picture )one that have the same letters on them which are 1FW 78 .i can’t seem to find this part anywhere nor nothing to do with it . So hopefully someone on here might be able to shed some light on this for me. Many thanks painner