When we were blocked from accessing HULU, we bought a new ROKU device, a Roku Express, to upgrade. However, wiring up the new device is not working. The previous wiring had a round connection going to 3 round connections on the HD TV who got a # of years ago. We found the TV HD connection portal for the new device, but it is not working. "No video signal" it says. Batteries installed. Plugged into power, but no service! Any steps missing?