Vizio TV (VA26LHDTV10T mfg. 2009) shows "No Support!" Roku Express 3930 is connected to HDMI1, and TV is set correctly to Source HDMI1. Same problem if using HDMI2. Does Roku Express 3930 not support this Vizio TV?
Try a different HDMI cable and make sure you're using the supplied power adapter and not the TV's USB port.
I agree with renojim. It could be the USB power that is giving you problems.
I'm guessing that "no support" message is from your tv, telling you that the Roku is sending a signal in a resolution which the tv does not support. If that's the case, you should see the normal "bouncing letters" Roku startup screen, but lose your picture when it tries to load the home screen.
I'd suggest trying the Roku on a different TV if one is available, especially if it has a working Roku. If it comes up okay there, go into Settings > Display type and change the Roku to the actual resolution of the problem set instead of the "auto" setting. When you get to the countdown screen click on the "yes" option. Now move the Roku back to the first set and see if it works.
Thanks for the tips. I tried all the recommendations and settings but the TV still shows "No Support". I used this TV and same Roku 3 for over a year but it all of a sudden stopped working. The Roku works with my other TVs but somehow stopped working on this older TV. Too bad since it as a nice smaller TV that I can move around but it needs the Roku since it is not a smart TV.
This TV does not have a USB port it's got two HDMI jacks and one rg8 for component only I also use a Roku Express but I have the newer model simply hook up your Roku to the HDMI and don't worry about usb you might be using an older model Roku oh yeah I got the exact same TV by Vizio
