Lenovo G505 Adapter & Battery Both Mode Does Not Turned On

FAULT :

1.     It turns on the Laptop normally with the battery, and it can be charged by plugging in the adapter after turning it on, which is completely normal. 

 

2.     If you use the battery and adapter but do not turn it on, the indicator light will light up for two to three seconds without powering on.

 

3.      3. When the adapter is not turned on, the indicator light will light up for two or three seconds, and the current is 0.007. It feels like the secondary 3-5V is not converted. 4 Turn off the Laptop to charge.

 

 

　　After disassembling the Laptop and measuring the isolation MosFet, they are all good and the conduction conditions are normal. The EC standby is normal, 3V5V is normal, 1.8V standby is normal, the LID signal is normal, ACIN is normal, and there is a jump in the power-on signal PBTN_OUT# from EC to the CPU when the power is turned on.

 

 

　　The Laptop has not been flooded and has not been repaired. I have no idea. When I saw the signal ADP_ID of the power port, I immediately operated it. Direct connection of pins 1 and 6 was useless.

Let’s do EC! I originally turned it on, and I planned to treat it conservatively, but I still went for major surgery. I specially found a new EC flash program, turned it on normally once, thought it was fine, washed it, and tried again, and it was the original fault again.

There was no change after heating up the EC. I searched for a material board to replace the charging chip and refreshed the BIOS, but it was of no use. When I was at a loss, I found that the Laptop still had a voltage of 0.95V in standby mode.

I found the inductor and measured no voltage. I measured pin 3 of 095_18ALW_PWR_EN3.3V. After cutting off the power and soldering the power supply chip, it was fine. Maybe it was heated here when I replaced the EC. It can be turned on.

Find the material board, remove a chip and replace it, shut down the Laptop and test it again, and the BIOS is flashed back. 

I tested again in the morning and still lost power, but this time the current went up to about 0.2, 0.95V was normal, and the heating was good again. 

This time I replaced both the upper and lower Mosfet. After leaving it for a day and continuing testing, there was no problem. The repair was completed.