# Vizio M550NV 55" No Video Input Detected



## rapter13 (Aug 17, 2008)

My Vizio M550NV 55" LCD tv recently stopped working "fully" it currently doesn't work on any video input port aside from the Tv Tuner input, but the video and sound still work perfectly. On all other inputs it just shows the screen "No Input detected" after about 10 seconds or so. 

Previous to it not working, it was only connected to a digital antenna and one hdmi cable, which was connected to my home theater system that housed all other connects, all devices are connected to a surge protector.

I removed the back panel to get a look at the main board to see if there was anything visually detectable and found no leaking or busted capacitors, or anything else that seemed out of place.

Any insight/suggestions or help would be appreciated.


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## Done_Fishin (Oct 10, 2006)

You say that it connects via your home theatre system .. i would suggest that you try to bypass that system and give a direct input if at all possible .. it could be that you are no longer giving an output via your home theatre system .. and thus looking in the wrong area for your fault.


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## rapter13 (Aug 17, 2008)

Done_Fishin said:


> You say that it connects via your home theatre system .. i would suggest that you try to bypass that system and give a direct input if at all possible .. it could be that you are no longer giving an output via your home theatre system .. and thus looking in the wrong area for your fault.


I had already removed the home theater system when I had tested it, using devices I confirmed to be working on another tv to test my hdmi vga component and composite connections.


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## Done_Fishin (Oct 10, 2006)

any way that you can get inside the "BIOS" and give it a factory reset ?? I know that this is normally possible but I regret that I don't know how ..


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## rapter13 (Aug 17, 2008)

Done_Fishin said:


> any way that you can get inside the "BIOS" and give it a factory reset ?? I know that this is normally possible but I regret that I don't know how ..


I have done a factory reset from the actual menu screen setup, but that didn't work previously, the only other thing I found for this model under factory reset was to unplug it from a power source and hold the manual power button for 3 minutes, sadly that didn't work either.


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## Done_Fishin (Oct 10, 2006)

I regret that leaves me no further ideas to offer .. I would need a service manual to see if there are any common power rails to the inputs that aren't working and see if any one item might cause the failure. 

you've tried everything by the sounds of it apart from trying to reload or upgrade the firmware .. and maybe you've tried that too but just haven't told us :lol: 

with the exception of getting another working set of the same type & model, then swapping panels, there is not much else to say or offer.


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## rapter13 (Aug 17, 2008)

Done_Fishin said:


> I regret that leaves me no further ideas to offer .. I would need a service manual to see if there are any common power rails to the inputs that aren't working and see if any one item might cause the failure.
> 
> you've tried everything by the sounds of it apart from trying to reload or upgrade the firmware .. and maybe you've tried that too but just haven't told us :lol:
> 
> with the exception of getting another working set of the same type & model, then swapping panels, there is not much else to say or offer.


I appreciate the help anyway, I've looked online to try and find a wiring diagram so I can see if there is some reason or way the power is bypassing the other components, but sadly all I have is the basic manual that comes with the tv. Which sheds no light on the issue. I suppose I will need to order a new mainboard and replace it if I can find a good website that actually has them in-stock :sad:.

Edit: I wish I had the tools they have to service and connect to these tvs, I know that connecting to the service usb port on some of the vizio tvs can brick them to "prevent tampering".


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## Done_Fishin (Oct 10, 2006)

rapter13 said:


> Edit: I wish I had the tools they have to service and connect to these tvs, I know that connecting to the service usb port on some of the vizio tvs can brick them to "prevent tampering".


you & me both .. unfortunately I have stopped repairing TV's since they went away from CRT tubes .. most TV's these days don't last much longer than the guarantee period .. that includes Computer monitors too .. I do see a lot of Computer monitors which come in for repair, but even so if it's not curable by replacing electrolytics then it's just not worth repairing in this throw away age.


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