My jvc lcd blackout after 1 second when turned on after that only sound coming but no picture

You will most likely need to get the set diagnosed. Sounds like you have a backlight problem. Backlight problems could be cause by a fault in the power supply, main board, inverter board, bad CCFL lamp, or a short in a HV(high voltage) cables. I would say it's worth getting a proper diagnosis. However, if you choose to replace the set, you can get a pretty penny for it on Craigslist. If it is clean and come stand and remote, you could get as much as $100 to the right buyer!

Blackout Mode On and Off

When the Blackout mode is turned on, the display will

turn off to reduce power consumption.

This additional power enhances the sound quality.

1 Press and hold the B.OUT button for at least 3

seconds to start the blackout mode. By doing so the

display will turn off.

NOTE

If any button on the unit is pressed during the blackout mode, the

function will be displayed for 5 seconds to show the operation

before returning to Blackout mode.

To cancel the blackout mode, press and hold the
B.OUT button for at least 3 seconds.

Sound like the power supply board has gone out .Unplug the tv for 2 or 3 minutes and plug it in again and try to turn on. Some times they will come on .But It sounds like the PSB is going out .

Blackout Display Mode: When the Blackout mode is activated, the display turns off to reduce power consumption. The additional power made available by turning off the display helps enhance sound quality. If a button is pressed during the Blackout mode, the display will illuminate for 5 seconds before blacking out again. Blackout Mode On and Off (CDA-9855 only) When Blackout mode is turned on, the display will turn off to reduce power consumption. This additional power enhances the sound quality. Press and hold FUNC. for at least 2 seconds to activate the blackout mode. The display will turn off. • If any button on the unit is pressed during the blackout mode, the function will be displayed for 5 seconds to show the operation before returning to Blackout mode. To cancel Blackout mode, press and hold FUNC. for at least 2 seconds.
Copied from the alpine user manual..
Hope this helps

1. hold the [vol-] and [menu] button.
2. while holding those, press the [power] button and let go of the [power]button only
3. wait 5 seconds then let go of [vol-] and [menu]
4. wait for a while(approx 30secs).....do you get a picture

This works for the JVC models that end in "9" and end in "0"

1. Hold [menu] and [vol-] button on the side of the TV
2. while holding these, press the [power] button on the side of TV (NOT remote)
3. blue light comes ON and stays ON
4. wait 10 seconds then let go of [menu] and [vol-]
5. wait another 30 seconds and some type of picture should appear

You are simply in blackout mode. This is so at night you aren't blinded by the glow of a screen. Here are instructions right from the manual to turn on or off.

Blackout Mode On and Off
When Blackout mode is turned on, the monitor display will turn off to
reduce power consumption.
This additional power enhances the sound quality.
1 Touch [VISUAL] on the main source screen.
The VISUAL selection screen is displayed.
2 Touch [OFF].
The backlit-display portion goes out.
3 Touch [OFF] again to cancel the display backlight.
• To make the setting, set to “Setting the VISUAL Touch Button” (page
34).
• If any button on the unit is pressed during Blackout mode, the
function will be displayed for 5 seconds to show the operation before
returning to Blackout mode.
• While the backlighting is turned off, the function indicator

i have taken the tv to repair shop a circut board has went on it

Sorry, this has no easy fix. The good news is you do not need an LCD Panel. The bad news is the Video Processor has a problem.
This TV has x3 Boards. The one you should replace first is the one in the middle. If this doesn't fix it, try the one on the right. The Part #s are on the Boards if you wanna try ebay.

You need an Analog Board. It is the one in the middle. You can find it on ebay for $50 I think.