Set Appliance State:
Set Multimeter to DC Volts 
Attach black crocodile clip to a suitable earth point
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Press and hold the power button on the front of the appliance for 5 seconds then release. (this puts the appliance into standby)
With a test probe on pin 2 of connector X9 press and hold the power button for 5 seconds then release. (this re activates the appliance)
Monitor the voltage as the appliance re activates.
The voltage should fluctuate very briefly (approximately 2 seconds) as the appliance switches back on and then settle at the original voltage of approximately 23.8 vdc.
Repeat the above for pins 3, 5 and 6.
Do the voltages on pins 2, 3, 5 and 6 behave as described?
With a test probe on pin 2 of connector X9 press and hold the power button for 5 seconds then release. (this re activates the appliance)
Monitor the voltage as the appliance re activates.
The voltage should fluctuate very briefly (approximately 2 seconds) as the appliance switches back on and then settle at the original voltage of approximately 23.8 vdc.
Repeat the above for pins 3, 5 and 6.
Do the voltages on pins 2, 3, 5 and 6 behave as described?
Isolate as per TOPs P4
and refit as necessary