Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect red wires from the clock

Measurement:

Test 1:
Measure the resistance between the disconnected clock connections marked 1 and 2.
Resistance should be approximately 70kOhms.
Test 2:
Measure the resistance between the clock connection marked 1 and a suitable earth point.
Resistance should be greater than 1M Ohm.