ON MY DIGISTar tv,there is lock symbol that has appeared on the upper left side. There is no fix for this in the user manual

The fault is with its main board itself. It will be best to get this set repaired by skilled technicians. This is not a user repairable one.

With service mode code, what are you going to do? It is locked!. You must first unlock it. Without unlock, it won't accept any remote signals. Try to download its user manual for details.

You have accedently locked your tV. What is the Brand name to your TV?

Hello
Your TV is locked.

The Child Lock feature prevents unauthorized viewing of the

television. To activate, press and hold the Function key, and then

press MUTE. you should see a key symbol appear on the screen.

This will lock out all remote functions (except for Standby). To unlock

the TV, press and hold the Function key and press MUTE. This will

unlock the TV. Please note that the only way to activate or deactivate

the Child lock feature is via remote control - please insure that it is
stored securely.

that would be you PIP (picture in picture) just press the PIP til it goes away

Unplug it from the wall for a few minutes.

Hi there. I had the same problem, as of a few minutes ago. I researched it online, you may have done the same and found the answer already, but here it is anyway: hold down on the display button for a few seconds. It only took me 2 or 3, but other sites recommend 5. It worked for me! I hope it has the same effect for you! I don't know how mine even locked...? 

Hold down the "display" button on TV remote for 3-5 seconds. It will take out of lock mode.

Press the DIS button (should be the orange one) on the remote for five seconds. That's how it got locked in the first place :)

Mine says 'Lock' / 'Unlock' when I do it, no key symbol.

Tony

i found the answer to my problem on one of fixya's message board.
THANK YOU. i turn on the tv using the remote then i pressed on the display key and a miracle happened, my tv was working.