GV42L HDTV picture ok but no sound.

check the sound settings in menu

This clock is supposed to have an automatically "increasing" volume feature (starts off low, gets louder over a minute or so).

If not sufficient, look on the top right side of the clock, there should be an up/down volume control. It is a black oval-shaped button with a picture of a sound speaker in the middle. Push it upward to increase volume and downward to decrease volume. Unfortunately, you have to have a flashlight or light on to see it because none of the controls are illuminated.

delete evrything you've downloaded for youtube and make sure you are on the sucre youtube website. Good Luck!

In the UK, there is talk of insisting the TV companies reduce the advert volume to the same level as programmes. There is a lift at present as it increases peoples awareness.

On the Unit itself, are Buttons, up to seven, 7, of them, usually, ON/OFF, MENU, Channel Up, Down, Volume Up, Down, SELECT/ENTER, Nearly ALL functions available on the remote can be performed via the buttons on the TV. Simply choose menu, and Step through with the Channel & Volume keys, and "Selecting" with the select/enter key. www.scribd.com/doc/.../VIZIO-GV42L-HDTV-Service-Manual
static.compusa.com/pdf/GV42L_HDTV_User_Manual.pdf - United States
Above are your User manual, above that is a service manual.

Mine does the same exact thing. Any ideas?

I have the same problem and it is just livable.  Turn on/off a couple of times and it will be OK.  Interestingly, The Samsung 40" LCD has a powersupply (bad capacitor) problem that seems to mimick this problem  There is a huge thread elsewhere on this Samsung issue, do a search.  Let me know if there is an explicit solution for this.  

The TV usually hums when the backlight setting is too low. So turning it up should get rid of the problem. To do this please follow these instructions:

1. Turn the TV on.
2. Press the Menu button on the remote, located right below the channel changing button.
3. Press the down direction button, located at the middle of the remote. Press that button until the backlight is highlighted.
4. Press the right direction button until the backlight is at 100.
5. Press the OK button and then the Exit button until you get back to your picture.

Good Day;

The TV's front panel may be bad, manual buttons. TEMPT FIX; remove speaker, cloth covered, cover, disconnect cables. TV will work but only with remote.

Good Luck!

I believe you have a regulation problem ,when you increase the volume the audio output IC draws more current therefore the power supply has to keep up with the increase in current,the symptom might happen if you increase the brighness to the max as well,the voltage changes need to be monitored closely to diagnose what component is not doing the work.If you are familiar with tv service this is a problem that will give you a challenge but if you are not too familiar be safe and let someone else get the headache.Let us know how it goes or if you need more information.