Try this, turn the unit on and when
green light come on, press and hold BOTH the menu and input buttons at the same time for at least 5 seconds and then release both.
This is the self check this model has---power light should blink a two digit code---for example--two blinks, a pause and two blinks and the set will repeat the error code about 10 times.
1 blinks and then 2 blinks is NO ERROR DETECTED
2 blinks and then 2 blinks is short
protect This is just to check for errors,
al through I
believe the Power supply and DM board on your unit may be bad.
Please rate and I will continue to advise.