When you try to open the dvd player locked is coming up on the display unit. what's the problem

Hold down the play button, it will take a bit but it turns of the child lock

If the Sony DVP-NS77H DVD player displays "TRAY LOCKED" and you can't eject a disc or open the tray, try the following - First turn the unit off. Then, while holding down the eject, play and stop buttons simultaneously (on the front of the DVD player), turn the unit on with the '/O button (also on the front of the player). This released the locked tray for me.

Step 1:
Initialize unit by simultaneously pressing Back Skip, Pause and Open/Close on the front of the unit. "INITIALIZE" should now appear in the
display and will remain in the display for a few seconds.

Step 2
With "INITIALIZE" still in the display, now simultaneously press Back Skip, Stop and Open/Close on the front panel. "ALL SET" should now appear
in the display.

Dear friend,
Press and hold stop+play button on the front panel of the dvd player more than 15 sec the player will be resetting

with the unit off press and hold the stop button and the eject button.

The Disc Tray Will Not Open And/Or There Is A Disc Stuck In The Player. Some DVD Players manufactured prior to 2003 have a Dealer Lock or Child Lock function. This will prevent the panel buttons from operating.

This function is activated by pressing the STOP button on the front panel
and the POWER button on the remote control simultaneously for four seconds in the power on state. Repeating this sequence releases the dealer lock. When the dealer lock in activated, DEALER LOCK ON or DEALER LOCK OFF scrolls on the display.

If this does not resolve your problem there may be an error with in the player. To resolve this try the following these steps:

1. Unplug the DVD player from the electrical outlet and leave it unplugged for thirty seconds.
2. Plug the DVD player back in to the electrical outlet, but do not turn the DVD player on.
3. With the DVD player off, press the [Open/Close] button on the front of the DVD player. The home theater should power on when you press the [Open/Close] button and eject the tray.

The second option worked for me...

have you tried to unplug the unit from the mains power wait around a minute and power back on if not press the setup button on the remote and reset to factory defaults.

Thanks J

press and hold the power button on the unit for 5 to 10 seconds

To turn on the dealer lock function: Turn the DVD player on. Press the Stop button on the front panel and the Power button on the remote control simultaneously for four seconds. Note: When the dealer lock function is active, DEALER LOCK ON or DEALER LOCK OFF scrolls on the FLT display. this is from samsung's site

To unlock, manually press and HOLD the open/close button & the stop button simultaneously, and HOLD them both down until the lock picture disappears.   The DVD will eject when you press the open/close button. 

 

To lock the DVD inside the machine, repeat the same step, and it will lock it inside.