A1534 820-00045 - USB-C not working both sides

[obelix24]

Hi All,

I just got one Macbook 12" that was not powering on. I found out that the battery was flat on right side so I charged it little bit with power supply and the MacBook turns on.

Problems that I have when I connect everything I can see for second apple logo and it it dims down, then there is apple logo with progress bar also only for second and then dims down. I found that issue is with trackpad (probably keyboard part) as when I disconnect keyboard from trackpad MacBook boots up normally. I took off the black cover on keyboard I was expecting some water damage but nothing it's spotless. When I connect keyboard to trackpad when MacBook is on display is immediately turned off / when I disconnect it it turns on immediately - I've ordered new trackpad to see if this is the problem.

But my main issue is that when I connect charger without battery it takes only 5V 0A. When I connect everything and plug in charger it takes 20V and A go up it charges battery for while (I expect that it charges battery but it's not it's only showing thunder inside battery icon, % are not going up)

USB-C port is turning on my ammeter only on one side when I flip it nothing happens (ammeter does not turn on). I've checked usb port and it looks ok from both sides also flex cable looks ok.

Can someone help me where should I check USB port sides ?
this lines are for 2 sides USB ?
E85_LS_P
E85_LS_N

I've tried to replace U4700 2x but the same.

[obelix24]

OK finaly i got it

problem was that PP5V1_S4SW_CC1 was shorted to ground I was checking via diode mode on J4700 PIN52 and the reading was 0,003V

It looks like the trace was going only to U7860 but even with this IC removed short was still there. I've soldered little wire to pin 3 (U7860) and injected 0,9V it was taking only 0,3A and nothing showing on this side of the board, i've flipped the board and U4700 was getting hot after removing this short was gone I've soldered new U4700 and checked diode reading PP5V1_S4SW_CC1 and it was here 0,4V.

After placing board back to case port was fully working 14,5V on both sides

Only issue left is that there is no sound from internal speakers If i connect headphones sound is working. I can adjust sound via keyboard and internal speakers are visible in MacOS by no sound via them

[mon2]

Re: A1534 820-00045 - USB-C not working both sides

Attach the trackpad. Meter in voltage mode.

Carefully measure the voltage to ground of:

SMBUS_SMC_3_SCL
SMBUS_SMC_3_SDA

Post each measurement. Given that the unit stops working when you attach the trackpad, the above SMBUS lines are a suspect.

[obelix24]

Re: A1534 820-00045 - USB-C not working both sides

I will check and post but to add.
Macbook doesn't stop when trackpad flex is connected or disconnected. On trackpad there is small board where connects keyboard one flex and then there is another flex cable that goes from this board to motherboard.

When I connect to this trackpad board keyboard flex and connect it to motherboard displays immediately goes off, but MacBook stays on, just the screen is off. When I leave trackpad board connected to motherboard and just disconnect keyboard flex from trackpad board display immediately turns on.

[mon2]

Re: A1534 820-00045 - USB-C not working both sides

Review the contacts of this keyboard flex. Swipe the contacts with IPA (alcohol) to clean these up of any possible residue.

Is the keyboard the original? Any history of liquid damage on the keyboard?

Does the trackpad function ok?

[obelix24]

Re: A1534 820-00045 - USB-C not working both sides

I've cleaned and check flex for keyboard and also the one that connects trackpad board to motherboard and they are in great condition (no damage) keyboard should be original and there were no signs of liquid damage on keyboard. When I've removed track I noticed there is something like rust or burned (small dot) but I was able to clean it, it was only on trackpad metal part and opposite metal part of chasi (not on any PCB). Trackpad is working now I've replaced one IC on trackpad board from another trackpad

[obelix24]

Re: A1534 820-00045 - USB-C not working both sides

Ok today arrived trackpad and the macbook is behaving same ...
So there is probably short on the keyboard. Is there anyway how can i inject voltage to keyboard connector to see which component is shorted (if there is) ?
I've attached photo of the keyboard connector.
Keyboard number is 820-00252-A but this gives me no schematics

[obelix24]

Re: A1534 820-00045 - USB-C not working both sides

Does anyone know if there parts are fuses ? (It's audio board) they looks to me like fuses and most of them beep if i test them only 2 not so i'm curios if this is why there is no sound

[obelix24]

Just received spare keyboard so I've replaced keyboard and MacBook is working fine. So problem was with keyboard.
But currently I've problem with battery - it's not recognized. When I connect charger it's not charging battery (battery should be ok as MacBook was running from it before)

Also when I connect charger I'm able to turn it on but in OS battery is not visible, but when I disconnect charger MacBook stays on (so the battery is giving power)

I've checked with diode mode connector J4700 (USB-C is connecting here) on pins
USB3_EXTA_R2D_N and USB3_EXTA_R2D_P I'm getting OL
E85_LS_N<1> and E85_LS_P<1> I'm getting OL
DP_E85SNK_ML_N<2> and DP_E85SNK_ML_P<2> I'm getting OL
on all other pins I'm getting I guess ok reading 0,003V (on ground) and from approx 0,3 - 0,8V on others

I've tried another USB-C connector and same result

can someone help how to troubleshoot this ?

[mon2]

Attach the battery -> meter in DC volts mode (20v or higher is ok). Measure the voltage to ground of each pin of the battery connector. Of most interest are the pins # 1 and # 3 = Battery ESD diode pins. Often, one of these dual diodes will get zapped from being man handled and the ESD diode @ D6950 dies as it should under an ESD event. This prevents the battery communication from working after such an ESD event. Confirm the voltage to ground of these pins and also confirm by using the meter in DIODE mode.

In DIODE mode, red meter probe (yes RED) to ground. Black onto battery connector pin # 1 - what is the measurement? Then repeat for pin # 3. If the ESD diode is damaged, the reading will be very different for that leg of the dual diode and should be close to 0 volts.

[obelix24]

I've checked and on battery pins I'm getting SMBUS_SMC_5_G3_SCL - 0,488V, SMBUS_SMC_5_G3_SDA - 0,588V
on D6950 I'm getting SMBUS_SMC_5_G3_SCL - 0,49V and SMBUS_SMC_5_G3_SDA 0,58V

[mon2]

So these SMBUS / I2C lines are not shorted. These measurements are good for a working pair of lines.

Just repaired an A1932 yesterday that came in with almost the same case as yours. Client reported that the battery would not charge. She purchased a fresh 20V @ 5A = 100W Type C power adapter to rule out the Apple original from being defective. Also purchased a matched 100W type C cable to power the target laptop. No change. We tested with our known power adapter & cable - no difference on the results.

We guessed it could be the battery but the Apple stats reported 510 charge cycles with NORMAL condition so battery is not the fault.

Observed that the Type C meter was stuck @ 5V and drawing ~1.9A which means the power up default of the power adapter is active - should be @ 20V unless the ACE controllers are defective.

Cringed at the thought of replacing the CD3215 controller(s) to fix this unit so kept checking. Laptop boots fine but after some wiggling of the type C connector - saw 20V. Proceeded to remove the USB-C paddle charge board and the view was like someone puked on the contacts. Attempted to clean with IPA and the results improved but not like a factory fresh unit. Fault is NOT with the CD3215 but now most likely a contact fault.

With 5A @ 1.9A - the charge stats reported it will take ~14 hours to charge the laptop battery. Not good.

Found a fresh new USB charge board and applied onto the unit. Laptop fixed to 100%. Now the battery charger (@20V) reports full charge cycle will be ~2 hours - perfect.

Take away is that the single wire BMC contacts on the Type C connector are key to dialing up the 20V power contract.

Do consider to test your logic board with a fresh USB charge board before proceeding further. These boards are available locally from Mobile Sentrix but you can buy from Aliexpress or similar.

At the very least - clean the contacts on the USB Type C connector on the laptop with IPA (alcohol).

[obelix24]

But my problem is that battery is not recognized. There is no battery icon in macOS and also in settings not battery detected. I've 2 usb-c cables for A1534 and they are 100% ok as I've tested them with another board.

[mon2]

Oh, thread title states:
USB-C not working both sides

Test with a known good battery. Your smbus lines are ok so the fault may be a defective or incompatible bms board on the battery pack itself.

[obelix24]

Yes because before battery was working fine. I've 2 batteries (one was showing as service needed but working and charging fine) but now none is recognized. I have also another board that is not working (but battery is charging, and also both sides of usb are working)

[mon2]

On post #10 -

1) are these voltage to ground measurements or diode mode measurements?

2) if diode mode measurements, remove all power and also remove the battery before using diode mode on your meter to test these smbus lines.

3) if voltages to ground readings then these values are not correct. Remove the battery and attach the power adapter and check these lines again to see if each line is at a higher voltage level. If not, the pull up voltage on this pair is missing.

4) if the voltage is ok without the battery pack but bad when the battery pack is connected then battery pack is defective.

5) if voltage here remains low but pull up voltage is ok then the esd diodes are damaged and they are pulling down these lines. Flux and remove the tiny esd diode pair. Measure again after the dual diodes have been removed.

[obelix24]

Reading are diode mode (power removed) red probe on ground black test point.
i've checked pp3v3_aon and the resistance is in Mohms ... according to repair wiki i've tried to replace U4700 but this didn't helped. I'm still getting only 5V and battery not recognized.

[mon2]

Share the voltage to ground while battery and adapter are connected of pins # 1 and # 3 on the battery connector = SMBUS lines.

[obelix24]

I've checked and
SMBUS_SMC_5_G3_SDA (Pin 3) I'm getting 3,2V but not stable it's jumping between 3,2 - 3.0V, 2,8V
SMBUS_SMC_5_G3_SCL (Pin 1) I'm getting 6,5V

I've checked also F7140 and it's ok on both sides I'm getting 7,28V

on PPVBAT_G3H_CONN I have 7,24V
on CHRG_BOOST_DL I've 0V
on PPVBAT_G3H_CHRG_REG I've 7,28V

Maybe U7100 is faulty ? (i would like to replace but i'm not able to find it for 2015 model only for 2016 and board 244 and i don't know if they're compatible.

[mon2]

Double check this measurement. It is too high as posted.

SMBUS_SMC_5_G3_SCL (Pin 1) I'm getting 6,5V

[obelix24]

I've checked it more times and it's 6.5V as mentioned.
I've another board but it's taking also 5V only but I tried to replace U7100 from one board to another and now it's still taking only 5V but now I can see on logon screen battery icon and also it's taking 0,2-0.3A from charger so I guess it's charging but really slow ...
Also both sides USB are working (but on both I'm getting only 5V)
Problem is that keyboard is not working at all ... mouse is working ok but there is no sign of life on keyboard ... I will try another keyboard
but I still don't understand what is responsible for USB (as on this board there is no CD32xx IC ...