Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Test 1:
Measure the voltage between pin 2 at X35 on the PCB to a suitable earth point.
Voltage should be approximately 22V DC.
Test 2:
Measure the voltage between pin 4 at X35 on the PCB to a suitable earth point.
Voltage should be approximately 5V DC.
Measure the voltage between pin 2 at X35 on the PCB to a suitable earth point.
Voltage should be approximately 22V DC.
Test 2:
Measure the voltage between pin 4 at X35 on the PCB to a suitable earth point.
Voltage should be approximately 5V DC.
 pcb in situ.gif)
 x35 on pcb.jpg)
Isolate as per TOPs P4
and refit as necessary