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Model Number A1707. Released June 2017, this MacBook Pro features Kaby Lake processors up to the 2.8 GHz quad-core Intel Core i7 processor with Turbo Boost up to 3.8 GHz.

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3 USB-C Charging ports of 4 stay on 0V, 4th port functions OK

I’m a repair tech guy, and I’ve run into a really weird issue with a 15-inch Macbook Pro with 4 Thunderbolt ports: out of 4 Thunderbolt ports 1 port works totally OK (charges, boots, all 100% OK), the other 3 ports stay on 0V even if I plug in the charger. Not even 5V. 0V 0A.

The working port is the top-left port of the macbook (on the left of macbook, closer to the screen; If you take out the PCB and put it CPU up, it will be on the top-right)

No corrosion of any kind. Was reported as “not charging“, another store replaced the battery and it didn’t solve the problem, so it came to me. That’s all the info I have.

Tools I use:

1) BY3200 power adapter with MagSafe 1&2 and USB-C power delivery integrated. So normally when I plug it in, I see 0V before plug in, jumps immediately on plug in to 5V, 2 seconds later it becomes 20V and the macbook starts to boot. In this specific case, it’s just 0V, I plug the cable in and it stays at 0V as if I didn’t insert the cable at all (in any of 3 ports).

2) Openboardview and PDF schematic for Board 820-00281

Things I’ve tried/checked:

1) Ports themselves are totally OK. I can swap left and right port flexes around, doesn’t change anything. One specific port works, others 0V 0A.

2) Fuses are all OK (F3000, F3001…). Besides, they’re all completely independent circuits, 3 completely independent circuits on different sides of the board go dead all at the same time? Something fishy is going on here.

3) No shorts found.

4) I have researched the schematic. Out of every 2 Thunderbolt controllers CD3215C00, one is primary and one is secondary. The working port is connected to secondary controller.

I still don’t understand how 3 completely electrically independent ports give 0V 0A while 4th port gives full 20V and boot. All power lines from the ports meet at PPDCIN_G3H, which is obviously not shorted because I can charge and boot from the 4th port.

I believe the problem is somewhere between PPDCIN_G3H (where power lines from ports meet) and Power delivery charger, there is simply nowhere else for the problem to be with such behavior.

To power the CD3215C00, I need 5V from charger to become PP3V3_G3H. Which is again totally fine since it works with 4th port. But I don’t even get 5V on charger on the 3 ports, which is what freaks me out and what I totally fail to understand and have never seen before.

Why would power delivery stay on 0V? How could 3 totally independent ports die at the same time? What do they have in common that the 4th port doesn’t have? I’m kinda lost here. Spent hours with the thing, no matter what I measure, nothing of interest comes up. Despite years of repairing Macbooks, I can’t solve this one and I’ve never seen anything like it.

Update (10/23/2021)

Interesting development: on the working port charging begins only in one cable orientation. In another one it's the same 0V 0A as if I connected nothing

Update (10/23/2021)

Further addition: the 3 works that don't charge simply don't work at all, USB hub doesn't light up when connected to one of those.

Отвечено! Посмотреть ответ У меня та же проблема

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Next development: did diode mode on the ports. VBUS one 3 non-functional ports is 0.18V, on the working port it's 0.13V. No idea how to interpret this.

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Update: new flex cables arrived. Nothing changed in behavior: 3 ports 0V 0A and don't light up the USB hub, 4th port works 100% correctly with only one side, another side 0V 0A too (same as before)

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You're welcome to propose new idea/solutions. I marked it as no fix and offered board replacement with data transfer (luckily the last working port will let me make a backup without problem). For a pair of days it will be around, then I will give it back to the customer. Still curious about what it could be, guess will never know tho.

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@ellectrician - Disconnect the ribbon cable to the port assembly and plug-in a spare unit does that fix things? Also try the other side as well.

You may have simply bad port unit assemblies

Also give this vid a watch from Louis Diagnosing USB-C muxing issues that prevent Macbook from charging

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I think I have covered this in my reply: one port works, I switch port flex cables around, only one same port keeps working. Doesn't matter with which port flex.

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@ellectrician - Moving the unit is not the same as getting a fresh part. MacBook Pro Retina (A1706 & A1707 Late 2016-2017) USB-C Board

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Alright, my logic is then the following: I take out the flex cable from the side where both ports are dead, I put it on the other side of board, and one of the ports starts working on that flex, just like it worked there with the original flex from that side. To me it seems like a clear indication the flex cables have nothing to do with it. You still think I should get a replacement port to be sure? Put a requisition order for a few flexes, probably worth checking out, in any case, replacement ports are good to have around. Should come next week, I will report of any changes. Let's pray this is all due to flexes. I doubt it, but want to believe.

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@ellectrician - Let me restate it so I'm clear: You have three bad ports in the fourth port the orientation of the cable plugged in alters it from good to bad (or the other way) You removed the port assembly from the case keeping track the iffy port and then swap it over with the fully dead assembly. Your logic is if the iffy port is still working (halfway) then it can't be the assembly. Is that what you are thinking?

I just find it easier having a spare part to use for testing that I know is fully good.

OK, let's dive deeper into the iffy port. The USB-C cable maybe bad or just not very good. I would try another cable to make sure that is not the case.

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Yeah, well, I see your logic. I mean, what else would it be. There are some vibes saying it's flex and some saying it's not, but there aren't many options that could cause this kind of faulty behavior, so let's hope you're right, I'm not discarding your version (and I don't have a better one anyway). As I've said, I'll report any changes. Probably next Tuesday/Wednesday. Thanks for the discussion.

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Ilya будет вечно благодарен.
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