Hi Everyone.
I am new to this forum and am excited to be a member.
I am an experienced troubleshooter who is terribly rusty at board level diagnosis and repair. I have most of the necessary equipment: ultrasonic cleaner, AmScope microscope, hot air station, hakko fx-951, quality fluke meter, power supply, etc.
I have a macbook air 11" MLB 820-00164 that I am using as a training board.
It has no liquid contact of any kind.
Did not power or have any magsafe light when I received it.
Troubleshot and repaired the one wire circuit (thanks Louis!) at and around U7090 (a couple dodgy traces and bad resistor). Magsafe adapter now lights up, but machine does not power UNLESS the flex cable from left IO board is disconnected. Machine will boot all the way to login.
Further troubleshooting found a bad Q3080 not passing PPVIN_S4SW_TBTBST_FET to pin 27 of U3090.
This may have been a lucky find as this circuit seem to be for Thunderbolt.
NOW: When flex cable is connected the voltage at cathode side of D3095 is 0V
When disconnected it is 15V
I am still getting familiar with the process and in understanding the various power states and how to determine this.
Any and all guidance would be greatly appreciated.
I am new to this forum and am excited to be a member.
I am an experienced troubleshooter who is terribly rusty at board level diagnosis and repair. I have most of the necessary equipment: ultrasonic cleaner, AmScope microscope, hot air station, hakko fx-951, quality fluke meter, power supply, etc.
I have a macbook air 11" MLB 820-00164 that I am using as a training board.
It has no liquid contact of any kind.
Did not power or have any magsafe light when I received it.
Troubleshot and repaired the one wire circuit (thanks Louis!) at and around U7090 (a couple dodgy traces and bad resistor). Magsafe adapter now lights up, but machine does not power UNLESS the flex cable from left IO board is disconnected. Machine will boot all the way to login.
Further troubleshooting found a bad Q3080 not passing PPVIN_S4SW_TBTBST_FET to pin 27 of U3090.
This may have been a lucky find as this circuit seem to be for Thunderbolt.
NOW: When flex cable is connected the voltage at cathode side of D3095 is 0V
When disconnected it is 15V
I am still getting familiar with the process and in understanding the various power states and how to determine this.
Any and all guidance would be greatly appreciated.