Found one broken pin on the connection point on my 820. has been an issue recently. I count 4 pins in the connector and 1 broken pin at the base level.
The USB cable seems to have 5 receptacles.
Laptop displays yellow ! text box - USB Accessories Disabled. Unplug the accessory using too much power to re-enable USB devices.
So now, can't charge, can't connect and upload.