Cant get channels even after channel scan. all snowy screens except channel 3 which is fish swimming around.

see if the is an AV button and press that
it changes"the signal in" source n ( pay channel,free to air antenna, x-box, dvd, etc)
the snowy screen indicates no signal and the icon is suggestingn it is looking for a input source

The remote doesn't effect the channels, I would say you have poor signal or interference from another device nearby.

Cable box not changing channels on VIZIO TV - Comcast Help and ...

forums.xfinity.com/.../Cable-box-not-changing-channels...TV/.../164607...

Apr 3, 2013 - I was able to connect my cable box and activate it without an issue. ... My problem lies in that the cable box will not change channels. Channel 8 comes in ..... I just unplugged the DTA ( you already did) and I let it sit for a while. No Audio with cable tv
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More results from forums.xfinity.com

Connecting Cable Service, Satellite Service, or Antenna ...

vizhdtv.com/connecting-cable-service-satellite-service-or-antenna-chann...

Mar 10, 2015 - If you are connecting your cable or satellite box using an HDMI cordyou will ... You just need to change the input of your TV then scan for channels. ... Except the Vizio TV will not receive a channel that all the other TVs get.

The tuner to this TV should be suspected. Replace it.

I notice that on mine, the positioning of the included tv antenna is very, very, very finicky. I also don't know how to "add" a new channel other than to hook it to the big house antenna and pick "re-scan" (or auto-scan or whatever it's called).

So I think your best bet is to pick a better antenna or know that even the tiniest fiddling with the antenna makes a diff. Sometimes, I even have the antenna horizontal (using the magnet) to get the good reception on a given channel. Seems like a hassle except that what should I expect from a tiny antenna....

Their is no more you can do.
You need a professional.
Stop using the TV until it is repaired.
Call the manufacturer to find you nearest authorized service center.

MR. TV Sales & Service Inc
Milwaukee Wisconsin 53405
(414) 762-8600
Established 1974

the 3 or for setting on the vcr is on the back( a switch)
or if the cable box has a channel 3 or 4 setting on the back of the box
but otherwise the tv may need some work on the tuner or need a new tuner

i dont have the instructions

If you are on cable, first run the cable wire from the wall directly to the TV, eliminating any cable box and/or VCR. If channel 2 is snowy but the rest (especially 3-6) are clear, it is most certainly a cable problem and not a TV problem. The TV uses the exact same circuits for channel 2 to 6 (VHF-LOW) so if the tuner was bad and 2 was snowy, 3, 4, 5 and 6 would be snowy too. Bring a second TV into that room, disconnect the cable wire from the RCA and connect it to the second TV. Is channel 2 on the second TV as snowy as it was on the RCA?

Probably needs a new tuner or something associated with the tuner.