MacBook Pro A2338 Arrives After Failed Repair Attempt
Reviving a “Dead” MacBook Pro A2338 – When the Real Culprit Was Hiding on the Logic Board
Every now and then a repair lands on the bench that has already had a bit of… enthusiastic attention. This particular MacBook Pro A2338 arrived from another computer repair shop with a simple complaint: the MacBook wouldn’t turn on.
The previous shop had already taken a logical first step. A new battery had been installed and one of the USB-C ports had been replaced. Both are sensible suspects when a Mac refuses to power up. Unfortunately, despite the fresh parts, the machine remained stubbornly lifeless. That’s when it was sent my way.
As is often the case with modern Apple devices, the real issue was not something easily solved by swapping modular components. This was going to be a logic board level repair.
Understanding the 820-02020 Logic Board Power System
This model uses the 820-02020 logic board, and like most Apple Silicon machines it relies heavily on USB-C power negotiation to wake up and request the correct voltage from the charger.
So the first step was simple: plug the board into a USB-C power meter and observe what happens.
A healthy MacBook should request 20V from the charger once the USB-C controller communicates properly. If the machine stays stuck at 5V, it usually means the negotiation process has failed somewhere along the line.
And that’s exactly what happened here.
Both ports were stuck at 5V.
But there was an important difference between them.
Port 1 behaviour
5V present
Small amount of current draw
Some life on the line
Port 2 behaviour
5V present
0 amps
No current draw at all
That second port was basically sitting there doing absolutely nothing.
In board repair terms, that’s a giant neon sign pointing toward the USB-C controller.
The Likely Suspect: The CD3217 USB‑C controller chip
Each USB-C port on this board relies on a CD3217 controller to handle power negotiation, data routing, and communication with the system.
If that chip fails, the charger never gets the message to supply the proper 20V rail, and the MacBook simply refuses to wake up.
The behaviour of port 2 strongly suggested a fault around the USBC IC, which is Apple’s naming for that CD3217 controller on the board.
To confirm the suspicion, I began measuring the surrounding components connected to that controller. Voltage rails, resistances, and surrounding circuitry all needed to make sense before condemning the chip itself.
After probing around the circuit, the readings told a clear story.
The controller wasn’t behaving as it should.
Diagnosis confirmed: faulty CD3217 chip.
Donor Board Surgery
Unlike larger components, these USB-C controllers are BGA chips (ball grid array), which means they’re soldered underneath with tiny solder balls rather than visible pins.
So replacing one isn’t a simple swap.
The replacement chip came from a donor board. First it had to be carefully removed using hot air and the board preheater. Once lifted, the underside of the chip looked exactly as expected — a landscape of microscopic solder pads.
Before it could be reused, the chip needed to be reballed.
Reballing involves applying fresh solder balls to the underside of the chip using a stencil so it can be soldered cleanly onto the customer’s board. It’s a delicate process that requires steady heat control and patience.
Once the chip was properly reballed, it was aligned and soldered onto the original 820-02020 logic board.
Then came the moment of truth.
Power Test
After cleaning the board and reconnecting power, I plugged the USB-C charger back in and watched the meter.
Instead of being stuck at 5V…
The voltage boosted to 20V exactly as it should.
The board sprang back to life.
Testing the “Replaced” Parts
Since the MacBook had arrived with a new battery and replacement USB-C port, I wanted to verify whether those parts had actually been necessary.
So I tested them individually.
Interestingly, the original battery was perfectly healthy, and the original USB-C port also tested fine.
Which meant the earlier replacements hadn’t been required at all — the real fault had always been on the logic board.
With that confirmed, I reinstalled the original battery and original USB-C port back into the machine.
Final Testing
Once the system was fully reassembled, I ran Apple Diagnostics to make sure everything was functioning correctly.
No errors. No warnings.
Just a fully revived MacBook.
After a final clean, the MacBook Pro A2338 was ready to head back to its owner — alive, charging properly, and doing exactly what Apple intended it to do.
Photos and Repair Footage
For those interested in the technical side of board repair, I’ve included photos and short video clips from the repair process throughout this post. You’ll be able to see:
The voltage testing on both USB-C ports
The faulty controller removal
The reballing process
The donor chip installation
And the moment the board negotiates 20V again
Sometimes a MacBook just needs a battery.
Sometimes it needs a port.
And sometimes it needs someone willing to look a little deeper than the obvious suspects.
Replacing and Programming the TBT ROM Firmware Chip
While diagnosing the USB-C controller fault on the MacBook Pro A2338, another issue surfaced during board inspection that needed attention before the machine could be considered fully repaired.
Close to the USB-C controller circuitry on the 820-02020 logic board sits a small but very important chip known as the TBT ROM chip. This chip stores firmware used by the CD3217 USB-C controller chip to manage USB-C power delivery, data communication, and device negotiation.
In simple terms, the CD3217 controllers rely on this ROM chip to know how they should behave. Without the correct firmware, even a perfectly healthy controller chip can refuse to function properly.
Discovering the Fault
During resistance checks around the USB-C circuit, the readings on the TBT ROM chip didn’t look quite right. Further testing confirmed that the chip itself was shorted, meaning it was effectively unusable.
Since this chip contains firmware specific to the board, simply swapping it without preparing it first wouldn’t be enough. The replacement needed to contain the correct firmware data for the board.
So the next step involved sourcing a replacement from a donor board.
Preparing a Replacement Chip
I carefully removed a compatible TBT ROM chip from a donor logic board using hot air. Once removed, the chip was cleaned and prepared for programming.
Before installing it onto the customer’s board, I connected it to a SPI BIOS programmer. This allows the firmware stored on the chip to be read, erased, and rewritten.
Using the programmer, I flashed the chip with the correct firmware for the 820-02020 board, ensuring it contained the proper data required by the USB-C controllers.
Programming these chips is a critical step. Installing a blank or incorrect ROM would prevent the USB-C subsystem from functioning correctly, even if the hardware itself was fine.
Installing the Programmed ROM
Once the firmware was written and verified, the newly programmed chip was soldered onto the logic board in place of the faulty one.
After installation and cleaning the surrounding area, the USB-C subsystem could now properly communicate with the newly installed CD3217 controller, allowing the board to negotiate power correctly and operate as intended.
These small components may not look like much, but without the correct firmware in place, even the most carefully performed hardware repair can fall short. Thankfully, once the ROM was programmed and installed, the USB-C circuitry behaved exactly as it should.
FAQ
Why is my MacBook stuck at 5V on USB-C?
If a MacBook remains at 5V and does not negotiate 20V, it usually indicates a fault in the USB-C power negotiation circuit, often involving the CD3217 controller chip.
Can a faulty CD3217 chip stop a MacBook from turning on?
Yes. The CD3217 manages USB-C power delivery. If it fails, the charger cannot negotiate the correct voltage and the MacBook will not power up.
What logic board does the MacBook Pro A2338 use?
The MacBook Pro A2338 with Apple Silicon commonly uses the 820-02020 logic board.
Is replacing the battery a common misdiagnosis for no-power MacBooks?
Yes. Many no-power issues are caused by logic board faults rather than batteries, particularly when the USB-C controller circuit fails.
MacBook Pro A2338 Repair in Birmingham
If you have a MacBook that is stuck at 5V or not powering on, we provide professional logic board diagnostics and repair services in Birmingham.
