Yamaha CVP 309 PE piano not start

Hi,
I have a Yamaha CVP 309 piano when the piano is switched on the backlight of the screen comes on, it adjusts the brightness but doesn't boot up.
I checked the ribbon cables to the display and the TR1 and TR2 boards the connection is good and the boards get supply.
I deduced that it could be the issue of either the DSP, the SDRam Chips or the E Buss chips. I can't find a replacement Dm2 board available, can you please help me out.