When i turn tv off and then back on it doesnt have volume if i turn tv off unplug HDMI cable then plug back in then turn on TV i have volume its annoying and NO ONE can figure out why it does that replaced 4 HDMI cables and the HD box

There could be a few possible issues causing the black screen on your Vizio M3D550KD. Here are some troubleshooting steps you can try:

1. Make sure all cables (HDMI, component, etc.) are securely connected to both the TV and the source device (e.g., cable/satellite box, DVD player, gaming console).
2. Try using a different HDMI cable to connect your source device to the TV, as the cable may be faulty.
3. If possible, test the TV with a different source device to see if the issue is with the TV or the original source device.
4. Unplug the TV from the power outlet, wait for a few minutes, and then plug it back in. This can sometimes reset the TV and resolve temporary issues.
5. Check the TV's menu settings to ensure the input source is correctly selected. Use the remote control to navigate through the TV's menu and adjust settings if necessary.
6. Perform a power cycle by turning off the TV, unplugging it from the power source, and holding down the power button on the TV for about 10 seconds. Then, plug the TV back in and turn it on.
7. If none of the above steps work, there may be a hardware issue with the TV itself. In this case, it is recommended to contact Vizio customer support or a professional technician for further assistance.

Some sets and devices have HDMI control that can turn off and on devices connected to them. Look into the settings of both devices and search for anything to do with HDMI control.

Try below and if still doesnt work itsbetter to call a repairman .
Here is the simple 5 step process we follow when this happens to our plasma tv. It works most of the time.
1) Completely unplug EVERYTHING connected to the tv, including HDMI cables
2) Press and hold the power button on the tv for 10 seconds
3) Plug power cord ONLY back in to TV
4) Turn tv on.
5) Plug in all other cables at this time.
It is helpful to use a good surge protector with this tv. It still goes out occasionally but not as much.
If the process does not work, wait longer (like an hour) after unplugging everything

I've seen this before, its usually a cheap or bad HDMI cable, try unplugging both ends and plug back in and then turn everything back on and see if that solves it. If not go get a new HDMI cable and try that.

Performing a power reset
1. Turn off the television.
2. Unplug the television power cord from the electrical outlet.
3. Let the television remain without power for 60 seconds.
4. Plug the power cord back into the electrical outlet.
NOTE: If the television is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the television.
5. Turn on the television.
How to establish an HDMI connection between a TV and other device.
Follow the steps below if the HDMI® connection between your TV and other device is not working:
1. Make sure both the TV and other device are turned on.
2. While turned on, unplug the power cords for the TV and device from the electrical outlet.
3. Disconnect the HDMI cables from the TV and other product.
4. Wait 60 seconds.
5. While the HDMI cables are disconnected, plug the power cords back into the electrical outlet.
6. Turn on the TV.
7. Re-connect the HDMI cables.
8. Turn on the HDMI-connected product.

The TV should now detect the HDMI signal from the connected device and operate normally. If there is still a problem, disconnect the HDMI cable from both products and then reconnect it in the opposite direction. In some situations this has been reported to resolve connection issues.
How to reset a TV to factory settings: https://us.en.kb.sony.com/app/answers/detail/a_id/61396
Hopefully this post helps you! If does, please mark it "accept as solution"

Do you see the volume indicator moving when you press the vol up/down?

Could the internal TV speakers have been turned off? This is done when using a sound bar or a AVR (Audio Video Receiver) aka Home theater

Sometimes you can unplug the hdmi cable and power off the tv and unplug power to tv wait 10 sec plug tv back in and then insert hdmi cable. Some of the newer tvs will auto tune to the input if that dont work, try getting a universal remote program the remote to control tv if you can control tv volume, power , menu then you should be able to navigate to the input menu and select hdmi that way

You need to replace the power supply, PN: ETX2MM704MGH. This 10 flash failure is common. I hope this was helpful, best wishes.

Is the HDMI port 2 work? Try to turn it off and turn it back on. If it is still not working then the HDMI ports have gone bad. You will need to replace the main board.

I recently had the same problem with my vizeo hdmi port # 1 going bad. Tried everything to fix and called vizeo. There solution for a master reset was turn off tv and unplug from the wall. then hold down the power button for 30 secs and let go. plug the tv back in and hold down the volume down and input select buttons down on side of the tv for 15 secs. release the buttons and turn the tv on after powering down all the components connectd to the tv. If this does not work they told me you need to have it sericed for a bad hdmi input. Hope this info helps anyone out there. It didn't work for me. Its a bummer cause the tv is well taken care of and only 18 months old. Best of luck to all others.