MacBook Pro: one USB port "dead", other works (sort of)

[RandyOo]

On a mid-2012 MacBook Pro 15" Unibody (820-3330 logic board):

This issue seems to have started after using the USB ports to charge R/C aircraft. I've tried SMC and PRAM reset, unplugging the internal battery, but no change.

The front port (closest to the SD slot) seems to be completely dead, and doesn't supply power to devices at all. Haven't checked with a powered hub yet, but I have a feeling that the data lines probably work fine.

The rear port (closest to Magsafe) works, but when I try to charge an iPhone, for example, it only works for a few seconds. I think it's requesting higher charge current, and then it cuts off. Other low-power USB devices seem to work fine on the rear port.

Looking at the schematic, it seems maybe U4600 is responsible for distributing the power to the two ports. I haven't tried any measurements yet, but wondering:

- is there a common failure point in this circuit? or...
- do these symptoms point to a specific component?
- any suggestions on where to start with measurements?

I have a friend who has equipment to handle surface mount soldering, once I can figure out the component(s) in need of replacement. Thanks in advance for any suggestions!

[jasko_jacker]

Re: MacBook Pro: one USB port "dead", other works (sort of)

u4600 receive 5v on pin 1 and 2 ?

[RandyOo]

Re: MacBook Pro: one USB port "dead", other works (sort of)

u4600 receive 5v on pin 1 and 2 ?

I haven't been able to check yet: I'm traveling at the moment, and the only multimeter I could find has very large probes. I was afraid that I might short something, so I'll wait until I have access to proper tools, then report back.

[rookieme]

Re: MacBook Pro: one USB port "dead", other works (sort of)

u4600 receive 5v on pin 1 and 2 ?

I guess you mean pin 2 & 3
pin 1 is ground

@RandyOo you can use a needle as a probe

[RandyOo]

Re: MacBook Pro: one USB port "dead", other works (sort of)

I guess you mean pin 2 & 3
pin 1 is ground

@RandyOo you can use a needle as a probe

Thanks. Got a chance to check today: 5.0 volts on pins 2 & 3, as expected. Also pins 4 and 5 have the expected 3.3 volts. Pins 9 and 8 match the values I measure at the USB ports: 4.7V on port A, and 2.0V and dropping on port B.

R4600 and the adjacent cap seem okay. And L4605 has continuity...

I'm starting to suspect D4600 for my problems with port A, because pin 1 to pin 6 of D4600 is low resistance. (D4700, service port B, showed "overload" when I checked reverse bias)

Will start with that one, since it's fairly simple. My friend happens to have a "donor board", so we can do some comparison measurements on that one, too.

[RandyOo]

Re: MacBook Pro: one USB port "dead", other works (sort of)

Came back to report that after replacing the TI TPS2561 IC, I got 5V back on both USB ports, and they both work fine.
(like this guy: https://www.stohn.de/3d/index.php/20...k-pro-13-2012/ )

[Superja]

Re: MacBook Pro: one USB port "dead", other works (sort of)

Came back to report that after replacing the TI TPS2561 IC, I got 5V back on both USB ports, and they both work fine.
(like this guy: https://www.stohn.de/3d/index.php/20...k-pro-13-2012/ )

Hi. Did you use TPS2561DRCR or TPS2561DRCT? I see a difference in Max static drain-source on state resistance, 50 vs 70 mOhms.
I have the same problem that you had.

[RandyOo]

Re: MacBook Pro: one USB port "dead", other works (sort of)

I used the TPS2561DRCT, and Mr. Stohn had used the TPS2561DRCR.

And for what it's worth, those ports continue to work perfectly.

[Superja]

Re: MacBook Pro: one USB port "dead", other works (sort of)

I used the TPS2561DRCT, and Mr. Stohn had used the TPS2561DRCR.

And for what it's worth, those ports continue to work perfectly.

Nice to hear that!! Then I think I'm gonna use CT as you did, but it seems both are ok. Thanks!!

[microkid]

Re: MacBook Pro: one USB port "dead", other works (sort of)

On a mid-2012 MacBook Pro 15" Unibody (820-3330 logic board):

This issue seems to have started after using the USB ports to charge R/C aircraft. I've tried SMC and PRAM reset, unplugging the internal battery, but no change.

The front port (closest to the SD slot) seems to be completely dead, and doesn't supply power to devices at all. Haven't checked with a powered hub yet, but I have a feeling that the data lines probably work fine.

The rear port (closest to Magsafe) works, but when I try to charge an iPhone, for example, it only works for a few seconds. I think it's requesting higher charge current, and then it cuts off. Other low-power USB devices seem to work fine on the rear port.

Looking at the schematic, it seems maybe U4600 is responsible for distributing the power to the two ports. I haven't tried any measurements yet, but wondering:

- is there a common failure point in this circuit? or...
- do these symptoms point to a specific component?
- any suggestions on where to start with measurements?

I have a friend who has equipment to handle surface mount soldering, once I can figure out the component(s) in need of replacement. Thanks in advance for any suggestions!

Hi - I am about to replace the TPS2561 as well, my Mid 2012 15" MBP (i7) has no USB ports. A local company (I do some work for) manufacture surface mount PCB assemblies and they are happy to do the work, I just need to supply the chip and show them where it goes - and that where I'm stuck I cannot locate it on the PCB assembly, I have looked around the USB ports but cannot see TPS2561. Could it be under the board? Are you able to provide any insight as to where it may be? Any help very much appreciated - thanks!

[piernov]

Re: MacBook Pro: one USB port "dead", other works (sort of)

Use schematics and boardview to locate it.

Note that there can be a lot of different reasons why USB won't work, and it's not because someone else had a problem with this chip that your problem will be exactly the same.

[microkid]

Re: MacBook Pro: one USB port "dead", other works (sort of)

Use schematics and boardview to locate it.

Note that there can be a lot of different reasons why USB won't work, and it's not because someone else had a problem with this chip that your problem will be exactly the same.

Yeah appreciate this, but would like to locate chip so I can check voltages around it. Looking at the schematic this chip does appear as the most likley culprit, and if not a good place to start poking about. The schematic I have is just a PDF of schematics, no layout diagrams.

[microkid]

Re: MacBook Pro: one USB port "dead", other works (sort of)

Where can I find an appropriate schematic / layout file to use in openboardview?