Switched bleeder resistor on a capacitive power supply
Use a relay driven by the rectified/filtered power. Connect the NC terminal to the bleeder resistor.







simulate this circuit &ndash; Schematic created using CircuitLab

Find a relay with suitable coil voltage to not need separate regulation/resistance for your output voltage.

Btw: Your diagram is DANGEROUSLY WRONG. With 120V AC input, the load/device you're showing marked as "64V" will see up to 180V, as the 120V is RMS-to-zero, not peak-to-peak, and if there is no load, the capacitor will keep the voltage at the peak value rather than the RMS value.

If you really need 64V unregulated, I'd recommend a 2.5:1 transformer added to your circuit. Also, the resistor in the diagram (please label your components!) seems like a waste. It will just burn off power if you draw power, and do nothing if you don't. If it's there to lower the voltage to 64V, then that will only happen if the load is very even and well-characterized. And the resistor will still get very warm -- power equals voltage squared divided by resistance. If it has to drop 100 Volts at 60 mA, it's about 1.7 kOhm, and 60 mA through 1.7 kOhm is over six watts!

I'm tempted to ask what probably you're actually trying to solve here. Working with mains power is pretty dangerous, and extra so if you're going to hook something into power permanently, or if anyone other than you will ever go near the device.