Dm 7020hd black display

[tamo]

I have an original DM7020HD. Suddenly its oled display becomes black ALL THE DISPLAY BLACK but j can flash with ip broswer or dream up when j made reeboot just have the image boot and nothing ellse and the led display disepire. I replaced the oled display with a new one, but unfortunately the DM remains with the oled black. Where could be the problem?
anyone help please.thanks in advance