If the system is equipped with a timer and you suspect it may be malfunctioning, remove Timer and test voltage at transformer receptacle. If reading is +/– 120 volts, you’ve got power to the transformer. You could also plug in a working light or appliance into the receptacle to see if there is power at the receptacle. Replace timer and test by manually turning the timer on (switch is on the upper left side of the timer). If the system does not come on, remove timer and plug pigtail directly into receptacle on face of transformer. If system now works, the timer is defective. Replace timer.
Note: Factory-installed timers have a maximum load capacity of 1750 watts. If daisy chaining transformers together in a master-slave configuration that exceeds 1750 watts of load, install a timer with the capacity to handle the additional load.
VERY IMPORTANT: The photocell is installed on the HIGH VOLTAGE side of the transformer! Be sure to unplug the transformer when installing the photocell.