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A2141 only working on battery

J

Jelle

New member
Dear community,

I received an A2141 for no power. I found some issues while scanning through the microscope and also while measuring.
CB300 was short
UB300 was suspect
UB400 was suspect
L3500 was liquid damaged
C9503 was ripped, including one of its pads.

After both UB300 and UB400 were replaced the device turned on again, but didn't take a charge from the USB-C power adapter. I tried several power adapters with sufficient watts.

At https://repair.wiki/w/A2141_2019_16"_MacBook_Pro I looked at the "No Power. No life on USB-C amp meter, or 5V ~ 0A." symptom and did find 3.3V on PP3V3_G3H_RTC_X and 12V at C6961. I was not sure how to check enable signal. On the other hand, I'm not sure if I should've checked any of these, because I have no clue where the problem originates.

I do have the schematics and the boardview so I can find what you point me at, though I must emphasise that I am absolutely a junior board repairder and might ask follow-up questions which might seem pretty novice. I can measure every pin of every component you might need more info from when I can find it on the boardview.

I await your reply.

Regards,
Jelle
 
2informaticos

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Where did you get the replacement CD3217 chips?
Do they have same termination code (B12)?
Some peoples mentioned to have problems and only succeeded with chips from donor A2141 board.

Do you have same behavior on all USB-C ports?
Only turns on with battery connected?
Be sure to use 96/140W original charger; check its power reported by an working machine.

Check if UPC_I2C_INT_L is steady high.
 
J

Jelle

New member
Thanks for the reply,

My colleague ordered these CD3217 chips:
On the chip B12 is printed.
I do not have a donor of this specific model.

The behavior is the same on all four USB-C ports. I used the original power adapter and a spare one which can deliver more.

I measured UPC_I2C_INT_L on pin 7 of J3000 and it reads 5.5mV. I expect that to be low and 3.3V or 5V to be high?

Edit: the above is measured with the battery disconnected and the original power adapter connected.
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
That signal must stay high.
If 0V (enabled), (at least) one CD3217 chip tells to T2 (SMC) there is a problem on USB-C area.
First check R5246.
 
J

Jelle

New member
I measured R5246.
Ohms in circuit: 2K (without power adapter)
pin 1: 1.803V (with power adapter)
pin 2: 5.8mV (with power adapter)
 
J

Jelle

New member
Is there a way to find out, or is it easier to just replace them? I already did the two easy ones. The remaining two have a plastic connector next tot them.
 
2informaticos

2informaticos

Administrator
Staff member
Peoples claimed on Internet to had problems replacing them on this particular board.
Not sure if works with other than chips from donor board, same model.

You may have more problems caused by corrosion.
 
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