Just to confirm
On the High Voltage board at connector CN101 you get 5v with the wires disconnected.
When the wires are connected from this connector to the main motherboard you get 0v on the motherboard where you should be getting 5v.
If this is the case I would check for any shorted capacitors, where the connector is on the motherboard there are some capacitors between power and ground I would check those first then check any capacitors shorts to ground.