Dell 15-7572 notebook can’t be turned on for repair

Dell 15-7572 notebook can’t be turned on for repair

Machine model: Dell 15-7572

Board number: la-f251p Fault

phenomenon: notebook Won’t Turn On

A Dell 15-7572 laptop, the fault is that auto power off,Won’t Turn On after auto power off, needs to be turned on after a few minutes, the boot time and date error.

resolvent:

1. Troubleshooting of heat dissipation;

2. Troubleshooting BIOS program;

3. Exclude memory Nand and other peripherals.

Start from the RTC circuit, the battery 3V is normal, through the circuit + RTC_VCC traced to the 20th pin of jio1, and then through r25021k resistance todiodeD2501 3rd pin, then d2501 outputs + RTC directly from 1 pin_Cell VCC 2.8V, measured VCC normal.

Dell 15-7572 notebook can’t be turned on for repair Figure 1.

Dell 15-7572 notebook can’t be turned on for repair Figure2.

Dell 15-7572 notebook can’t be turned on for repair Figure Figure 3.

Through the running line + RTC_After the cell was basically normal, it was found that there was only 1.9V floating up and down in the first pin of q1901, and VCC 2.8V at one end of rc57 resistance measured by the drawing was normal. First remove cc25 and then measure q1901.pin VCC is normal. Find a Capacitor on Parts motherboard and replace it. The tester has no problem for 3 hours. The maintenance is over.