Dell15-3520 (LA-L947P) No CPU Power Repair

Laptop Model: Dell15-3520 

Board Number: LA-L947P 

Repair Process:

1.     When the laptop turned on, and each voltage is measured. There is no CPU power supply. Check the drawing that PUZ101 power supply is normal, and the open pin 51pin is low level.

1.     Check the IMVP_VR_ON_EN signal to the fourth pin of UC8, and measure the high level of pin 1 and the low level of pin 2.

1.     Check pin 2. IMVP_VR_EN is sent from the C2 pin of EC. It seems that the timing needs to be checked.

1.     The condition for IMVP_VR_ON_P to be turned on is that ALL_SYS_PWRGD is high level and the measured low level is.

ALL_SYS_PWRGD is sent by 1.2V_VTT_PWRGD. The measured 1.2V_VTT_PWRGD is low level.

1.     1.2V_VTT_PWRGD is sent out by the 10^TH  pin of the memory power supply chip PUM01. The 1.2V memory power supply and VTT Voltage must be normal. The measured 1.2VP voltage is normal and the VTT voltage is 0V. The start signal pins 8 and 7 are all at high level and pin 20 is not short-circuited to ground.

1.     After replacing the memory power supply chip RT8207 , the computer started up smoothly.

Happy Repairing!!