Martin FiberSource QFX 150 User Manual page 21

To replace t he secondary fuse
1 Disconnect the fixture from power.
2 Remove one screw by the DIP-switch and one screw by the data IN socket.
3 Pull the circuit board assembly out until you can access the fuse, which is
located behind the data IN socket.
4 Remove the defective fuse and replace it with one of the same type and rating.
5 Replace the circuit board assembly before applying power.
Basic service 21