Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Gain access to PCB (use Insulation Mat as required)
Disconnect rectification lead from electrode assembly

Measurement:

Measure the resistance between the end of the rectification lead to pin 4 (white) at LV1 on the PCB.
Expect continuity / zero resistance.
Inspect lead and connector for good overall condition.
Are the checks satisfactory?
Note:
Connector may differ slightly in appearance but this does not affect the test.