This boot is not displayed, but you can read disc play, others are normal. Users say that they replace the laser head failure in the future. After the aging laser head does not read disc, users pull to change the laser head, replacement can be read off the disc, but the screen is not displayed. Split machine seriously observation Hou found, transformer of main circuit board Shang has a small of sparking points traces, measurement screen voltage in the No-28 v, this voltage from transformer motherboard, through several ban tube processing obtained, sparking of spots just is located in transistor of c very, split down measurement has short-circuit, estimated is split laser head machine frame of when no pulled power, will machine frame of iron seat and transistor collide, burned has transistor, replaced Hou boot displayed normal, fault excluded.BABservice manual download site