This is a "Hailin switching power" DWP1070 power supply but that got me
nowhere.
From the IR datasheet Vcc is enough to get the controller started and both
control voltages are the right side of thresholds for operation so a mystery
why no oscillation.
The relay supply is taken back across the HV/LV divide, rectified from its
own winding on the switching transformer, so no oscillation , no relay click
over