Hardware Repair for Nighthawk AC1900 DOCSIS 3.0 High Speed Cable Modem Router + Voice (C7100V)

Thank you for your response. Here are the answers to your questions:

Can you give us a bit more detail? When I put the plug the electric cord into the modem/router I sometimes had to shake it to energize the device (make a connection). Over time I had to shake it more and more before I got a connection. Evently, shaking did not help and when I now plug it in it is dead in the water. I changed the electric wire and it worked a couple of times and then it stopped working with the new plug. 

How did you diagnose this issue? See above

How do you know is is a "bad plug connection"? see above

What is the "plug connection"? What connects to what? One end of the electric wire connects to the wall and the other end of the wire connects to the modem/router. The end that connects to the wall has a standard 2 prongs that fit into the wall receptacle.The end that connects to the modem/router has 2-slots that fit over two round prongs in the modem router.

What is the "motherboard"? The on on the modem/router? Something else? I took the modem/router to two repair shops and both said the model/router has a electrical connection soldered on the motherboard. Neither of the repair shops do soldering work. That is the reason I am here so someone may direct me to a repair shop for a Netgear modem/router where I can send the device. It is a very expensive device and if I can not get the hardware repaired I will end up throwing away my investment. I live in a small town outside Nashville and I have tried all the local repair shops. No help.

Thanks