Broken Intel MBP's top left USB-C/Thunderbolt 3 port?

TidBITS Talk
1

Hello,

A 2020 13.3" Intel MBP (A2251 model; MWP62LL/A)'s top left USB-C/Thunderbolt 3 port stopped working for power charging and connecting with original Apple USB-C power and third party power adapters (e.g., Anker). I even tried to connecting Apple’s USB-C Digital AV Multiport Adapter and iPhones, but macOS Ventura v13.6.7’s top right notification says “USB Accessories Disabled – Unplug the accessory using too much power to re-enable USB devices.” even with direct iPhone connected with USB-C and lighting cables! Also, no HDMI video too.

The other three ports worked fine so I suspect this port is busted. I looked inside and things looked OK (not dirty and dusty), but it was tiny and hard to see inside. Does anyone know what else to try? I wonder if it got fried inside. I sniffed that port and didn’t smell anything unusual. My client said that port stopped working during his out of country week hot and humid trip.

Thank you for reading and hopefully answering soon. :)

2

I just tried two USB-C hardwares (a flash stick and a mouse) on this “broken” USB-C/TB3 port. Both also failed to connect and macOS Ventura v13.6.7 says “USB Accessories Disabled – Unplug thew accessory using too much power to re-enable USB devices.” Console app and Terminal app’s dmesg command showed this interesting line: HS02@14200000: AppleUSBHostPort::interruptOccurred: overcurrent detected with port status 0x4000, localSimulatedInterrupts = 0x0

I think this hardware port is broken. What do you think?

3

Sounds like a repair trip to Apple is in this Mac’s future. I don’t know Apple Diagnostics would shed any light on the situation, but it might be worth trying.

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4

Good idea, Adam. With the external hardware accessories (Apple’s USB-C Digital AV Multiport Adapter with ASUS VA27DQSB 27" 1080P monitor(HDMI)) connected to the broken USB/TB3 port, I ran its offline diagnostics (why did it need to go online to run it in Internet Recovery mode? I thought macOS Ventura provided that already in MBP’s SSD). It did not find any issues found after a few minutes of testing like in https://cdsassets.apple.com/live/7WUAS350/images/macos/big-sur/macos-big-sur-apple-diagnostics-results-no-issues.jpg screen shot.

5

While sometimes helpful, I have never put tremendous faith in the Apple diagnostic tools. Of course those tools may not provide any clue if there is some odd system/software corruption causing that port to be unusable.

I wonder if it is worth booting off a clean system via external SSD and try the port again?

6

Ah, a good idea with an external live bootable media. I wonder if I can use Linux, but which one to use?

7

I’d try some magic voodoo that sometimes works for problems like this first. Try resetting the NVRAM and the SMC:

Note that after resetting NVRAM, some system settings may have reverted back to factory defaults. In particular, you should reset your Startup Disk preference afterward, in order to avoid a delay at boot time (caused by waiting for storage devices to come on-line and searching them for bootable volumes).

It may not help, but if it does, it will save you a trip to the repair shop.

1 Like
8

Thanks David. Resetting NVRAM and SMC didn’t change anything assuming I did them correctly. :( I will go to Apple store if I lose more ports. Thanks God I have four in total. No AppleCare too. I am going to assume they would have to replace the whole motherboard and that is not going to be cheap.

9

You’re correct. Apple or an Apple authorized service professional will replace the motherboard and charge quite a bit to do it.

An independent repair shop could probably identify and replace the failed component (likely to be something like a USB interface chip or some related components on the board), but Apple has used its leverage over chipmakers to ensure that nobody else can buy the replacement chips, even though they are generic commodity chips with trivial changes, like which signals are on which pins. So repair shops are forced to scavenge them from dead boards.

This is one of the critical Right-To-Repair issues that nobody in government or industry wants to even talk about, let alone do something about. When lawmakers talk about making parts available, they only think about entire assemblies (e.g. complete circuit boards), not the assembly’s components (e.g. the chips on the board).

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10

So, this confirms a broken port since booting a bootable USB Ventoy with Debian stable (live) doesn’t get seen during MBP’s boot up with option key with disabled security and allowed boot external drives (this part was news to me). Same in Debian live with an external USB device. :(

Thanks to all who answered to help. :)