Macbook pro touchbar A1706 820-00923-A not charging

[Mikyjordan]

Hello everyone,


I'm new to the forum, and I've heard great things about this community, so I decided to join, hoping you can help me.


The story of this Mac is a bit complicated. Let me explain step by step:

1. The customer brought me a Mac that wouldn't turn on. Using a USB tester, I measured 0V and found the CB300 shorted. I replaced it, and the Mac powered up again.
2. The computer works only with external power, not with the battery. It charges the battery correctly, but if I disconnect the external power, it shuts off.
3. Unfortunately (my mistake), while performing some measurements, I short-circuited a component (see attached photo) and possibly something else. As a result, the ISL (U7000) burned out, and the Mac got stuck at 5V.
4. I ordered two ISL chips from AliExpress and soldered both. However, a new issue arose: the Mac works on battery power but not with external power. The USB tester correctly detects 20V, and the Mac recognizes that external power is connected, but it doesn't charge the battery.
5. This issue occurs with both ISL chips (I’d like to rule out that both are defective). Specifically, the Mac powers on normally with the battery installed, but not with external power alone.
6. If I remove the battery, the USB tester shows current oscillation between 0.020 and 0.180 mA. When I connect the battery, the USB tester oscillates between 0.000 and 0.008 mA.

Here are my measurements:

• PPVIN_G3H_P3V3G3H: 21V
• PP3V3_G3H: 3.2V

Thank you all for your support. I hope to make my customer happy. I look forward to your advice and suggestions for further tests.


P.S.: Apologies for my English—I'm Italian, and this text was translated using ChatGPT.

 

[2informaticos]

First of all, welcome to the forum!

Is your board 820-00239, or 820-00923?
Not big difference, but is always better to use the correct schematic.

You made short between C7060 (20V input) and R7075 (used by internal 5V LDO).
I bet this resistor is burnt; check that.

 

[Mikyjordan]

First of all, welcome to the forum!

Is your board 820-00239, or 820-00923?
Not big difference, but is always better to use the correct schematic.

You made short between C7060 (20V input) and R7075 (used by internal 5V LDO).
I bet this resistor is burnt; check that.

I tested R7075, and it doesn’t seem to be burnt. However, the strange thing is that it should be 4.7 ohms, but it measures 4.7 kOhms. My board is 820-00923-A.

 

[2informaticos]

"R7075, and it doesn’t seem to be burn
..................
it should be 4.7 ohms, but it measures 4.7 kOhms"
Isn't that enough to consider it burnt???

BTW, write directly into bottom reply box, instead of clicking Reply button.
Please, maintain forum aesthetic...

 

[Mikyjordan]

You're absolutely right, it’s burnt. In the meantime, I soldered another 4.7-ohm resistor. After powering it up, the USB tester showed different values. Then I measured the resistor again, and the new one was also burnt, reading 4.7 kOhms. Something is burning this resistor. Can you confirm that R7075 should indeed be 4.7 ohms? If so, what could be causing this resistor to burn?

 

[2informaticos]

Change both C7075/77...

 

[Mikyjordan]

Thank you for your support. I replaced the two capacitors, but it doesn't seem to have had any effect. However, the customer called me and said they bought a new computer and no longer want to repair this one. Thank you, you are amazing!

 

[2informaticos]

Did you also replace R7075 again?

Make him an offer and get the Mac; not too much money.
It can be repaired probably; or you keep it for spare parts.

 

[Mikyjordan]

I didn’t change r7075. I have hasked to my customer 80€ for reapair. However, I also offered the client to purchase their broken computer, but they said they would think about it and had it returned to them.
Then if you want you can close this post
See you to the next repair