Franc,

These are the results

Zener markings I could see N1 & A

power off R series resistor ~22M Ohms

Zener Test with Ohmmeter of Multimeter

Negative Probe on Cathode (Black Strip) ~140 K Ohms

Positive Probe on Cathode (Black Strip) ~167 K Ohms

power on

Vin ~111 V

Vout to 0 V ~200 mV

"If the diode is reading a much lower voltage than its rated voltage, such as near 0V"

From tests seems Zener is Shorted.

Since the zener was destroyed from a "power surge" what upgrade do you suggest to prevent this from happening?

Ken