Vizio GV42LHDTV No Digital Channels

[102mm]

Re: Vizio GV42LHDTV No Digital Channels

https://www.youtube.com/watch?v=qC9FEZ78-qM

[Loudhvx]

Re: Vizio GV42LHDTV No Digital Channels

Hi, I realize this is a really old thread, but I thought I might be able to add some info to it.

First, I want to thank everyone else who posted here.

I am working on a Vizio VX37L. The tuner portion of the main board looks pretty much like the one on the GV42L. And I have the same problem. The autodetect completes the analog channel search, but does not even begin to search the digital channels. The progress bar does not turn yellow at all.

However, my problem is more intermittent in that it did work one time, then found about 70 channels. But later that day the TV only had a blue screen and no channels worked except the one analog channel. After that the autodetect never worked again on the digital search.

I tried the various suggestions posted here, but I don't have a remote. It seemed like I could do most everything I needed with the buttons on the side of the unit. The "unchecking" the individual channels could not be done. The checks were grayed out.

Based on 102mm's post, above, and the excellent video, I opened the unit and checked the 1.25v regulator. It was rock solid.

So then, as a last resort, I popped open the RF enclosure. Inside was what I assume is a really tiny potentiometer. I rotated it back and forth multiple times, probably like 20 times, vigorously. I made sure to note what position it was in, and put it back to that position.

This seemed to fix the problem, but I can't say for sure it wasn't something else I may have touched. The digital channel search progress bar immediately had a tiny portion turn yellow, and after about 2 or 3 minutes it found 70 channels. I reassembled the TV and after 24 hours, it is still working.

[Loudhvx]

Re: Vizio GV42LHDTV No Digital Channels

I wanted to post several photos, but I guess I don't have permission to access my profile page yet.

[Loudhvx]

Re: Vizio GV42LHDTV No Digital Channels

Since I can't put up photos yet, I should mention, the potentiometer I exercised was a small metallic one, which appears like a small rivet or small screw-head. I don't think it would be recommended to exercise the variable inductors. They look like rectangular cans with a dark adjustment screw inside the middle. Those screws don't make direct electrical contact, so there would be no benefit to rotating those.

[Andrew F. Ali]

Re: Vizio GV42LHDTV No Digital Channels

The cans with the dark adjustment screws are actually coils with a ferrite bead in it (no physical contact) and as you adjust the dark screw or ferrite bead the number of Micro-Henries or Milli-Henries change in a tuning circuit. DON'T adjust these.

[Loudhvx]

Re: Vizio GV42LHDTV No Digital Channels

I can now post photos, so here they are. I also included photos of the regulator that "102mm" replaced in his video.

Cover over main board.


Main board exposed.


RF enclosure.


RF enclosure with lid popped off.
Don't adjust the inductor can (left of pot in photo). Only the tiny potentiometer.


Closeup of potentiometer (center of photo).
Don't adjust inductor (left side of photo).


Main board showing regulator marked AMC 1117 F0632J


Regulator marked AMC 1117 F0632J

[Loudhvx]

Re: Vizio GV42LHDTV No Digital Channels

The cans with the dark adjustment screws are actually coils with a ferrite bead in it (no physical contact) and as you adjust the dark screw or ferrite bead the number of Micro-Henries or Milli-Henries change in a tuning circuit. DON'T adjust these.

Yes, I mentioned that in the post before yours. Maybe you didn't see it. But thanks for the confirmation.

[newbie48]

Re: Vizio GV42LHDTV No Digital Channels

I realize this is an old posting and no one will probably see this but hey nothing ventured nothing gained. I have a 2007 Vizio GV42L HDTV too which I love with same tuner issue ie won't scan for digital, just the analog. I tried all the suggested fixes; the last one being the take TV apart (a challenge) and wiggle the wee pot as suggested by loudhvx. No change. Tried it again. Still nothing. I give up. I think I am going to try the external tuner solution that FriedFarmer I think talked about having as they are cheap ($25-$30...much cheaper than taking TV to repair shop) and give you features not included with TV like DVR functionality.

[nomoresonys]

Re: Vizio GV42LHDTV No Digital Channels

Well here's some more crap to try: https://www.fixya.com/support/t23906...ed_getting_all