Dell magazine G3 579 laptop can't be charged and repaired

Dell magazine G3 579 laptop can’t be charged and repaired

Machine model: Dell Travel Box G3 579

Main board number: LA-F611P Rev:1.0

Malfunction: The laptop can’t be charged.

Maintenance process:

A DELL G3 579 laptop, the fault is that it is not charged, and the adapter switches back and forth with the battery. After changing two batteries, it still doesn’t charge, and the power supply and battery switch back and forth all the time.

Dell magazine G3 579 laptop can’t be charged and repaired Figure 1.

The BIOS of this machine is common failing. Brushing the BIOS is fruitless. It turns out that the battery and adapter switch back and forth, and it can’t be turned on directly after brushing the BIOS. According to schematic paper measurement, PQ7 has been welded, and VCC is normal at the beginning of measurement. When the G pole of PQ7 is found to have 17.8V, it immediately reflects that PQ7 is broken.

Dell magazine G3 579 laptop can’t be charged and repaired Figure 2.

Re-measurement found that PQ7 was originally a P tube, which was replaced with a new one, and the G pole was measured at 17.8V.

Dell magazine G3 579 laptop can’t be charged and repaired Figure 3.

Then, the signal PQ15 2 pin that controls the G pole is on, and it is normal to pull down PR22 and turn off PQ16 PQ21. It is also normal to turn off the signal PQ152 pin, 3 pin and 2 pin. The resistor is not installed here.

Dell magazine G3 579 laptop can’t be charged and repaired Figure 4.

Look ahead for +3.3_ADP_DCIN from PU01, whose 1 pin 19V 4 pin 2.5V is normal, and whose 5 pin has no output.

Dell magazine G3 579 laptop can’t be charged and repaired Figure 5.

When the chip changed to PU01 19V, PQ7 G was more than 9V normal, but the battery still had auto power off when it was turned on, and it was changed to 95522H, and everything was normal.