I have a laptop to repair, with these details, it is an Asus rog zephyrus s15 gx502 laptop, and the only problem is this: the laptop turns on and everything works, but there is no display on the laptop LCD, while everything is fine with the hdmi port. This problem occurred when the battery socket was disconnected from the board when removing the laptop battery. Currently, everything works properly with the hdmi port, but there is no display on the laptop LCD. The important point here is that the 3.3v lcd voltage is present for a few short seconds during startup and then it is disconnected. In fact, according to the laptop map, the lvdd-en in u4503 is quickly disconnected after startup, and therefore the 3.3v lcd is disconnected. On j4502, pins 34, 35 and 36 have no voltage even at startup, but pins 37, 38, 39 have a stable voltage of 20 volts. Meanwhile, the resistance of u4503 to ground is 10 kilohms and has a normal temperature. The lcd cable is also healthy.