Today i decided to power on my LEDs on front of the object i work in. They have blinked some times and that was.

The adapter has been used very very seldom.

It maybe will be good to put my new unused osciloscope for first time in use with some good ideas from you

thanks

 

So your power supply may be dead or your LEDs might be dead. You have not reported enough information for anyone to make a better guess. Take some measurements with a multimeter and report back. You don't need an oscilloscope yet. Start with the basics. Power at the wall socket? Power at the PCB? At the output? Do the LEDs still work? Simple stuff first.