A1534 820-00045 - USB-C not working both sides

[obelix24]

ok so update...
Reconnecting keyboard flex cable was issue and now keyboard is working
battery charging is working but only at 5V. I now really don't know what can be problem that it's taking only 5V but charging.
I've tried another battery and this one is not service required but still only charging at 5V ...

[mon2]

Would you have another meter to test the voltage measurements?

The posted smbus voltage readings are too high.
Remove the battery to check if the same smbus pins are lower.

[obelix24]

I've checked now battery and charger connected (macbook turned on)
SMBUS_SMC_5_G3_SDA (Pin 3) I'm getting 3,3V
SMBUS_SMC_5_G3_SCL (Pin 1) I'm getting 3,3V

should i try to replace U4700 one more time ?

[mon2]

What is the voltage to ground of PPDCIN_G3H ? It should be 20v for the proper charging and operation of this macbook.

Are you using the official and recommended power adapter? At least consider to use 65W or higher power adapter. U4700 is the Silego (SLG4AP645AV) device that will communicate with the power adapter to select the 20V power delivery contract using the CC1 / CC2 lines.

Are the contacts on the Type C contacts clean? We did go down a similar rabbit hole a few weeks ago for a few minutes and found the only fault was the actual physical contacts were very dirty. Too dirty to even clean with alcohol. We had replacement USB C paddle boards for the macbook brought in for service. The client purchased new cables / new power adapters from Amazon with hopes of a quick fix. Suspecting her cat was the guilty party of this case.

[obelix24]

I'm using official 61W power adapter with official USB-c cable.

PPDCIN_G3H - 20V

[mon2]

Good.

Remove all power. Remove the battery. Meter in the lowest resistance mode.

Measure the resistance between points A & B. Post the measurement.

[obelix24]

resistance is 13 ohms (between A and B)

[mon2]

Short your meter probes. What is the resistance measurement?

The resistance of this path is too high. It should be ~2 ohms.

[obelix24]

when I short probes resistance is 0,3ohm
on another a1534 board resistance between A and B is 2 ohms

[mon2]

Ok - so this is a fault. Need to determine between the 3 resistors in this path - who is guilty.

Measure these points again and if you do not see ~2 ohms, proceed to check the resistance of each resistor.

Measure the resistance across R7151 (pin #1 & #2) - should be ~1 ohms.
Measure the resistance across R7152 (pin #1 & #2) - should be ~1 ohms.
Measure the resistance across R7151 (pin #2) & R7152 (pin #2) - should be ~0,3 ohms since this current sense resistor is in milli-ohms if it is ok. That is, your meter will not be able to measure it neither will our $1,000 fluke so we only want to see like a dead short = 0,3 ohms at this junction.

Someone in this path is not behaving.

[obelix24]

R7152 - resistance approx 2ohms
R7151 - resistance 11 ohms (so it looks like this is faulty I will try to replace)

[obelix24]

I've replaced R7151 and now resistance is OK, but MacBook is behaving same.
Still only 5V on charger

I've checked PP3V3R3V0_AON and resistance is in Mega ohms - this should be ok.

I'm thinking if not U4520 or U4440 are bad ...

[mon2]

Remove all power / remove the battery. Review the battery mosfet @ Q7155.

Measure the resistance across the mosfet pins:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement.

Still only 5V on charger

meaning that you have 5 volts @ PPVBAT_G3H_CONN ?

[obelix24]

on PPVBAT_G3H_CONN I have 8,7V when MacBook is powered on
When it's off I get there only 0,7V but falling down....

according to Q7155 I think it's ok
source (1,2,3) to Drain (5) - 40k ohms
source (1,2,3) to Gate (4) - 2,8M ohms
Gate (4) to Drain (5) - 4,7M ohms

but as I wrote before. Macbook is charging battery but only at 5V and max 0,2-0,3A (I was able to charge the battery to 94% (before it was approx 20%)

also one strange thing. Even battery is almost fully charged (94%) when I reconnect everything I'm not able to turn on MacBook with power button. I have to connect USB-C power adapter to turn it on.

I've checked with thermal camera and there is still only U4440 getting warm (I tried both sides USB). I was expecting that U4440 is for one side and U4520 is for other side. Or am I wrong ?

[mon2]

40k resistance on Q7155 is considered to be low for a mosfet. Carefully flux and remove this mosfet for checking out of circuit. Compare to a known good unit and it should be with a higher resistance.

[obelix24]

Looks like i wrongly measured. After remeasure the value is approx 2M ohms also between source to drain.
What do you think about replacing U4440 or U4520 ?

[mon2]

U4440 is an analog switch / multiplexer for usb signals. Are you facing any usb data faults? Would you have a usb hub? Test with your system if a mouse works, etc over usb. If it works then this mux ic is not defective.

are you using a known good battery? Do not charge with outside hack methods. It can kill your battery pack and can be rejected by this logic board. Suggest to get a virgin battery for this model and test again.

[obelix24]

I was waiting for replacement IC's for U4440 and U4520. I've replaced both and MacBook is behaving the same ...
I'd working and charging but only at 5V (0,3A) and only on one side (when I flip USB-C cable nothing on meter.

I've tried also USB-C dongle that I have and charging still only 5V. When I turn USB-C charger it's not detected.

I've uploaded short video on YouTube to show how it's behaving.

https://youtu.be/MiuSz37dDOk?si=tAFkzPgHYr6QPuWo

[mon2]

Check each LDO rail of each CD32xx ACE controller. Each controller must be working for the 20v rail to be dialed up for the power delivery contract. Review the wiki on how 20v is selected.

https://logi.wiki/index.php/CD3215_Bootup_Sequence

[obelix24]

But on this board there is no CD32xx