The hdmi port of my vizio e231-b1 smart tv is not working. It displays either "No Signal" or "Not Support!" How can I fix this?

If your Denon AVR-888 is not passing HDMI signal from your Asus UX431F laptop to your Vizio TV, but is passing signal from your Apple TV, there may be a compatibility issue between the laptop and the receiver or between the receiver and the TV. Here are a few things you can try:

1. Check HDMI cables: Make sure all HDMI cables are properly connected and working. Try using different HDMI cables to see if that resolves the issue.
2. Update firmware: Check if there are any firmware updates available for the receiver and the laptop. Updating the firmware can sometimes resolve compatibility issues.
3. Check laptop settings: Make sure the laptop is set to output video through its HDMI port. On some laptops, you may need to manually select the HDMI output in the display settings.
4. Try a different input: If your receiver has multiple HDMI inputs, try plugging your laptop into a different input to see if that resolves the issue.
5. Contact the manufacturer: If none of the above steps resolve the issue, contact the manufacturer of the laptop, receiver, or TV for further assistance.

It's also worth noting that some older HDMI receivers may not be compatible with newer HDMI devices. If your receiver is several years old, it may not be able to pass the HDMI signal from your laptop. In that case, you may need to upgrade to a newer receiver that supports HDMI 2.0 or higher.

In most of the case, the main board is out.

Do other inputs work?

Sounds like you have a bad capacitor. Likely overheating. Likely going to need service or replacement.

Google how to spot a bad capacitor. They pop up and get a brown dot in the center. They are easy to spot.

Unfortunately, you fried the HDMI controller. Not necessarily part of the power supply "main board." (Not sure which board is the HDMI controller in your specific TV. It's usually a separate board by itself). Easiest workaround is to use the "Component" cable connectors. The downside is you only get 720P. However, most cable/satellite and _all_ antenna signals are only 720P anyway. Most people only see 1080P when viewing Blu-Ray discs. Aside from replacing the HDMI controller, the cheapest workaround for multiple source connections is to buy an HDMI to Component Converter A/V box, which allows you to connect multiple devices to one box with one set of Component cables connecting to the TV. Then select various "sources" via the box.

Something wrong with your HDMI port. Check at TV tech service or claim warranty if new

What is the problem you faces with this TV? If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/

Here is a link to the manual for both the E231-B1 and E241-B1.
http://www.vizio.com/documents/downloads/hdtv/E241B1/UM_E241B1.pdf

HDMI specification allows both video and audio to travel over a single cable, however, the signal source must offer both signals as well. There are instances wherein only the video is transmited. This especial true when using a computer as the source signal. In some instances a cable may be required to feed the audio into the video card. In other configurations this is acomplished through software in either the bios or control panel.

If you're trying to display output from the laptop to the Vizio you'd be better off using an HDMI to HDMI cable. The VGA port on the Vizio E320 only supports 640x480 resolution; you have to set your display output accordingly, usually in control panel. Using HDMI you're able to keep the signal HD, @720p. The E320 also supports 1080i, but you're not going to see all 1080 lines. If for some reason you're trying to go from the Vizio to the laptop it just doesn't work that way.