How can I locate the fuse in the Nexus control box?

On older models - these are located alongside the timer blocks within their own hinged compartments. The fuses are all standard glass fuses; 10 Amp, 5 Amp, 2 Amp, 2 Amp from left to right.

On newer models - there is only one 5 Amp fuse located on the left hand side of the relay block.