Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Gain access to PCB (use Insulation Mat as required)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Locate connector X51 on the right hand edge of the PCB.
Test the voltage to earth at each of the red wires leading to the display PCB.
The readings should be approximately as in the table below:
Test the voltage to earth at each of the red wires leading to the display PCB.
The readings should be approximately as in the table below:
| PCB Pin | Voltage (DC) |
| GND | 0v |
| RES | 5v |
| +5v | 5v |
| 24v | 24v | RXD | 5v |
Isolate as per TOPs P4
and refit as necessary