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Macbook Pro 2018 only charges with 2 things connected a1990

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andersonamr

New member
Hi guys, i have this a1990 the costumer brought in that only charges the battery when connected the charger and other thing inserted.
When we connect only the charger, it turns on normally, but won't charge. But as soon as you connect a pen drive, it automatically starts charging.
Already tried changing the ports, problem not solved.
Installed new usb ports, same.
Tried another charger, same.
Didn't tested another battery.

No liquid spill, no signs of corrosion, no signs of fisical damage. All normal, except for the fact that it gets hot with only web browsing.
 
A

andersonamr

New member
Allright, i'll add more info.

Tested new usb-c ports and we have the exact same pattern as the originals.

There are 2 ports on the left, two ports on the right side.
Left side ports are both OK, but not charging as mentioned.
Right side, only the top one works, bottom one won't turn on the usb amp meter.

Teste new usb-c ports and we have the same outcome, only top one works, bottom won't turn on usb amp meter.

Still, no charging at all.
 
A

andersonamr

New member
More info...

When turned off, it charges normally.
Top and bottom right side usb-c ports working normally, both charging (when powered off).
 
A

andersonamr

New member
Found minor corrosion on QB651 and QB660, i'm kinda afraid of removing then not knowing it's really related to the problem.
 
2informaticos

2informaticos

Administrator
Staff member
CC1/2 lines are involved in charger recognition.
So you definitely must clean and rebuild mentioned area.
 
A

andersonamr

New member
Allright, cleaned the corrosion, which wasn't affecting anything. Any ideias where to go next? Board is all good, no more signs of fisical damage or corrosion.
 
2informaticos

2informaticos

Administrator
Staff member
That port still keep USB meter black?
Compare diode mode readings on CC1/2 lines between all ports.
Check at connector side and also CD3215 chips.
 
A

andersonamr

New member
On the side of usb meter is BLACK:

USBC_TB_CC1_CONN 0.550 Diode Mode
USBC_TB_CC2_CONN 0.750 Diode Mode

On the side of usb meter is NORMAL:

USBC_TB_CC1_CONN 0.748 Diode Mode
USBC_TB_CC2_CONN 0.750 Diode Mode


I assume CC1 is where the problem lies, right? How do i proceed from that?
 
A

andersonamr

New member
Had some changes after removing QB650 from the board just to test behaviors.

3 ports are working fine on both sides of usbc, 20v 0.4ma without charging.

1 port shows 5v 0ma on usb meter, but changing the cable side, it goes to 20v 2.5a and charges the mac.

Here's a video of the behavior:
 
Last edited:
A

andersonamr

New member
Something i didn't mentioned before, the mac only turns on with battery connected.
Without battery, all 3 ports that are "good" gives me 20v 0.02ma.
 
A

andersonamr

New member
Alright, found the "problem".

On the side of usb meter is BLACK:

USBC_TB_CC1_CONN 0.550 Diode Mode
USBC_TB_CC2_CONN 0.750 Diode Mode

On the side of usb meter is NORMAL:

USBC_TB_CC1_CONN 0.748 Diode Mode
USBC_TB_CC2_CONN 0.750 Diode Mode


This 0.550 reading was coming from the UB400, reballed him and nothing changed.
Took a CD3215 from a donor board of an A1706 and the reading is now 0.750, like all other ones.

I thought it was it and my job was done, but NO. Macbook starts, powers on normally, but now ALL 4 ports have the same behavior: 20v 0a draw. System doesn't recognize when cable is plugged.

Good side is: All ports are "ok", the black one is back to life.

I'm assuming this cd3215 i've used is faulty. Makes sense? I don't have other cd3215 which is sad.


Is there any compatibility issues with different models and cd3215s?
 
2informaticos

2informaticos

Administrator
Staff member
Did you use the same termination code for replaced CD3215 chip?
QB650 has been resoldered?
Tried to power the machine with both charger and battery connected?
 
A

andersonamr

New member
YAYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Yes, cd3215 was the same termination code.

QB650 wasn't the fault by itself, it only had to take the USBC_TB_CC1 that goes through RB650 into the QB650 to work properly, which is created by the UB400/CD3215.

It should've worked from the start, but making the steps back, i noticed my soldering skills were deteriorated by the 8h hour sraight i was working on this machine.
Reballed again the new/same cd3215 and it worked like a charm!

Thanks buddy!! You rock.
 
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