Hello,

I am trying to repair a Logitech LS21 multimedia speaker system (Model Number S-00042).

There is a small switched-mode PSU which I have opened up inside the main sub-woofer unit. The soldered inline mains fuse was blown.

There was some blackening around a few surface mount resistors. There is a short across the Drain-Source of the MOSFET transistor (WFF2N60).

Should I just replace the transistor and fuse or there likely to be some other cause?