820-02016 - MacBook Air Not Charging - Changed Two Type C Chips

[mccafe]

Hello,

I have a MacBook Air that does not charge. Amp meter showed 5 volts for both ports, 0 amps. Changed both Type C chips and now we get 20 volts and 0.28-0.32 amps. It turns the computer on, but does not charge the battery. Tried new battery and it is still not charging.

Any advice? Thanks!

 

[2informaticos]

Is the battery recognized by macOS?

Check voltage and diode mode to ground on all SCL/SDA lines of UD200/1.
D5150 is the first suspect.

 

[mccafe]

Voltage while charger and battery connected. (Diode mode - board only)
I2C_SMC_PWR_SCL = 0.008v (0.003)
I2C_SMC_PWR_SDA = 1.2v (0.300)
I2C_SMC_PWR_1V8_SCL = 0.008v (0.450)
I2C_SMC_PWR_1V8_SDA = 1.8v (0.490)

D5150
Pin 2 = I2C_SMC_PWR_3V3_SDA (0.488)
Pin 1 = I2C_SMC_PWR_3V3_SCL (0.008)
- I temporarily removed D5150 and I still see the same diode measurements.

I compared J5150
Known good board for the two data lines = 0.500 on diode mode.
Bad board shows I2C_SMC_PWR_3V3_SCL = 0.850 on diode mode and I2C_SMC_PWR_3V3_SDA = 0.500 on diode mode.

I am unable to determine if battery is being detected. With and without the battery, the home screen shows a battery symbol with like 5% charge. I am unable to login or go into Diagnostic because the MacBook would just restart.

 

[2informaticos]

"Pin 1 = I2C_SMC_PWR_3V3_SCL (0.008)"
Is that is diode mode reading?
"Bad board shows I2C_SMC_PWR_3V3_SCL = 0.850"
And what's this then?

Please, post accurate information.
You may need to change both UD200/1.
Be sure first, all their pull-up resistors are good.

 

[mccafe]

I am not sure how I got 0.008 for I2C_SMC_PWR_3V3_SCL I was almost certain that was the measurements. I am now only seeing 0.850. All pull-up resistors for the data lines check out. I'll need to source out UD200/1 and hopefully it does the trick.

RD200 actually has low resistance 1.6K Ohms, so UD200/1 is probably bad.

 

[mccafe]

Replaced both UD200 and UD201 and the voltages remain the same. Still not charging the battery. I also replaced U5200.

UD200
I2C_SMC_PWR_1V8_SCL = 0v (0.480)
I2C_SMC_PWR_1V8_SDA = 1.8v (0.490)

I2C_SMC_PWR_SDA = 1.2v (0.300)
I2C_SMC_PWR_SCL = 0v (0.004)

UD201
I2C_SMC_PWR_3V3_SDA = 2.8v (0.480)
I2C_SMC_PWR_3V3_SCL = 0v (0.480)

D5150 (same measurements with it replaced or removed altogether)
I2C_SMC_PWR_3V3_SDA = 2.8v (0.480)
I2C_SMC_PWR_3V3_SCL = 0v (0.480)

The board however now shows 0.480 on diode mode for the 3V3_SDA / SCL lines. Previously, SCL was higher at 0.850.

 

[mccafe]

I was able to attach a battery that had a charge and the MacBook would boot all the way and run off it, however the system does not detect it. It is showing an X in the battery symbol. I replaced RD200 / 201 another time with no change. I removed RD200/201 and made some measurements. All resistors and voltages check out except I2C_SMC_PWR_SCL seems to be pulled down by the CPU.

 

[2informaticos]

"I2C_SMC_PWR_SCL = 0v (0.004)"
There is short to ground; impossible to have communication.

Apart of UD200/1, only M1 remains there.

BTW, none of RD20x resistors could cause short to ground.
Don't waste time removing and testing them.
Pull-up resistors may be suspected when you have missing voltage, but without short, or low resistance to ground.

 

[mccafe]

Oops sorry, yes I meant to say I removed UD200/201 and not RD200/201. I am guessing this one is going to be unrepairable. Super unfortunate considering the MacBook turns on and works fine with a charged battery. Is it possible that something else is causing the M1 to short this specific line down? These two data lines go to BC3 and BC2 on the M1 chip. Just below is BB2 which is I2C_SMC_UPC_SDA (0.300 on diode) and it connects to the two CD3217 chips that had to be replaced earlier.

 

[2informaticos]

If that lines is shorted to ground with only M1 connected, then nothing to do.