MacBook Pro 15" 2017 A1707 Touchbar No power

[Ajbernasko1]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Hi, I am back to let you know I tried so many ways to find a problem on the board and guess the technique I used ?

1) With all power removed the coils do not have a short; but when an adaptor is plugged in, I see the PP5V_S4 (L7600) is shorted (20 ohms) and cannot turn on to 5V just zero,

2) With all power removed, I injected 5V onto that rail and I saw U7800 lighting up to about 38 degrees celsius with 0.03Amps.

3) I pull the PMIC out and the rail is not shorted again (I injected 5V again then 0 amps draw). I guess now I will have to replace the PMIC. I did replace U7650 and didn't solve the issue. Please post your replies so I can know the way forward. I heard shoutouts from KamiL to Piernov on this same issue later when I looked up for this issue from YT.

[ajbernasko]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Voltage and resistance are fine. So the ESD device is not impacting the communication lines.

1) Are you using the official power adapter or one that is capable of powering this logic board ? Suggest 60W or higher power supply.

2) After the board powers off -> check the voltages of PPBUS_G3H.

3) What is the history of this unit ? Just died one day or for some other reason ? Do search for clues on the logic board.

Continue to review the other suggestions above while I take care of my weeds...err lawn.

1)official 60W

2) stays at 12.6

3) Customer was selling it off so had to wipe it out before final sale, then now powers on alright but do not stay on for more than 1 minute.

[ajbernasko]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

1) No, do not have any other device to test it.

2) 2.195 V on the battery. connect the com to - and the Red probe to + on the battery board

3) PPVBAT_G3H_CONN is 12.66 V

4) @ Q7065, pin # 1-2-3 (SOURCE; PPVBAT_G3H_CHGR_R) = 12.66v

5) TBA_CSO_N = 12.66v
TBA_CSO_P = 12.66v

6) Q7065 , shows 10 M ohms rose up to 50 MB ohms then 0L for all 8 pins. all measure in diode mode and the mosfet seems fine.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Voltage and resistance are fine. So the ESD device is not impacting the communication lines.

1) Are you using the official power adapter or one that is capable of powering this logic board ? Suggest 60W or higher power supply.

2) After the board powers off -> check the voltages of PPBUS_G3H.

3) What is the history of this unit ? Just died one day or for some other reason ? Do search for clues on the logic board.

Continue to review the other suggestions above while I take care of my weeds...err lawn.

[ajbernasko]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Hi Brother,

Thank you for getting back with your reply. I have located the D6950


PIN 1 - SMBUS_SMC_5_G3_SDA = 3.398 - 3.401 ,
PIN 2 - SMBUS_SMC_5_G3_SCL = 3.398 - 3.401

The reading isn't stable for both pins, started reading from 3.0 M ohms and declined till it stopped at 130.2K

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

See attached.

1) Is the battery a known good battery ?

2) what is the present voltage on the battery ?

3) Measure this voltage @ PPVBAT_G3H_CONN and post the voltage value. This is the voltage that is being used to interface with the logic board via the battery mosfet @ Q7065.

4) Leave the power adapter OFF. Using only the battery, what voltage do you see @ Q7065, pin # 1-2-3 (SOURCE; PPVBAT_G3H_CHGR_R) ?

5) With care, take the measurements of the following pins:

TBA_CSO_N
TBA_CSO_P

This is the current feedback loop used by U7000. The ISL9239 IC takes as input the voltage on each of the above legs and monitors the voltage drop across the current sense resistor @ R7060.

Based on the voltage drop, U7000 is able to determine if there is too much of a load on the logic board and will shut down the use of the battery mosfet and/or charging.

So it is important that the resistor values remain as per the original PCB assembly schematic. Respectively, the feedback voltage must reach the ISL9239 otherwise it assumes that the voltage drop is caused by a dangerous and excessive load and is beyond the expected current draw -> shut it down mode.

6) Will be a good idea to check if the battery mosfet (Q7065) is ok with a resistance check.

Remove all power / remove the battery. Meter in resistance mode.

Measure the resistance of Q7065 as follows:

Source (1-2-3) & drain (5-6-7-8)
Source (1-2-3) & gate (4)
Gate (4) & drain (5-6-7-8)

Post each measurement and the meter scale used. If your meter shows '1' or 'OL' then the meter scale is too low -> switch to a higher scale till the meter is able to measure the resistance values. Too low of a reading means this mosfet is leaking / defective and must be replaced.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

The battery BMU communication is over the I2C / SMBUS interface. Locate the battery connector and in the schematic will be a dual ESD diode component.

Often it is D6950 but do confirm the reference in the schematic. I do not have the schematic in front of me at this time.

Once you find this part, measure the voltage on the SCL pin to ground. Meter in 5 volts dc or higher.

Repeat to measure the SDA voltage to ground. Post each measurement.

Next, remove all power. Meter in resistance mode.

Check the resistance to ground of these same pins.

We are checking to see if this dual esd diode is defective which will halt the proper operation of these common communication lines.

[ajbernasko]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Hi Mon2, finally you are up to help me as well ?

Appreciate you I hope we can start working on this now. Board is 820-00281-A, 2016.

1) It shows 19.3V, 0.9399 amps then kind of goes back to 0 amps after it cycles(0.9399 - 0.000) about twice then stays on 19.6V 0.00 for the board only when battery and bmu cable is connected to the board; it starts at 19.6V 0.00 then I see 11V / 13V at 0.00 then 4.99V the cycles between 340ma, 370ma, 24ma, 27ma, 24ma 0.00ma.

I also saw that when BMU cable is connected to the board(without battery) it reads 19.6V 1.1amps then stays at 19.6V 0.00. PPBUS is 12.6 either way

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

What is the 820-xxxx board number on your A1707 logic board ?

1) Does your power adapter go to 20V to power your logic board ? Do you have a USB C meter ?

2) See attached. Measure the voltage of PPBUS_G3H at the referenced fuses.

[Ajbernasko1]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Also our board is
820-00281-A

Hi everybody, I have a A1707 MacBook 2016 that turns on then powers off after few minutes. It cannot turn on when I use the PSU only with the type-c charger or battery. Now there's no os on it. SSD does not show when booting from drive on startup however it does show in disk utility. It powers off after about 1-2 minutes into installing OS from storage drive.

PPBUS 13V

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Agreed. Sounds too hot.

Perhaps consider to reflow the hot CD3215 ? Maybe it is damaged but try the reflow again.

hi,

Reflowed UB300.
UB300 is now reading 130 mA about.

UB400 has good readings on LDOs and no shorts but does not power on.
Perhaps it's poorly connected on the power lines or broken.
I tried to reflow it, no change.

the ports on the other side work too somehow, 130 mA about.

I suppose UB400 needs to come off again, but given that I have no reballed spare or reball solder, I have to leave it for now.

Unfortunately I do not have time for a while to pursue this, I will probably order some reball solder or more chips, depending on if I find another broken one.
Lack of time sucks, might keep it for spared for a while.

It has been a great learning experience and I hope to get back to it.
@powerblackout would you mind uploading the TBT rom incase me or anyone else needs it?

Thanks a lot!

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Agreed. Sounds too hot.

Perhaps consider to reflow the hot CD3215 ? Maybe it is damaged but try the reflow again.

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

hi, thanks for the quick response.

The readings for LDOs are:
u3100 :
pp1v8_upc_xa_ldod : 0.466
pp3v3_upc_xa_ldo : 0.480
pp1v1_upc_xa_ldo_bmc : 0.486
pp1v8_upc_xa_ldoa : 0.503

u3200
pp1v8_upc_xb_ldod : 0.458
pp3v3_upc_xb_ldo : 0.479
pp1v1_upc_xb_ldo_bmc : 0.477
pp1v8_upc_xb_ldoa : 0.496

ub300:
pp1v8_upc_ta_ldod : 0.450
pp3v3_upc_ta_ldo : 0.478
pp1v1_upc_ta_ldo_bmc : 0.474
pp1v8_upc_ta_ldoa : 0.490

ub400:
pp1v8_upc_tb_ldod : 0.458
pp3v3_upc_tb_ldo : 0.484
pp1v1_upc_tb_ldo_bmc : 0.474
pp1v8_upc_tb_ldoa : 0.492

so those look all good?

I never touched the chips before, but got as warm as close to burning my finger, does not feel good.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Confirm the diode readings of both U300 & u400.

Measure the diode readings of the other CD3215 devices on the board and compare if their readings are similar and in this range.

Post the values.

Was U300 more warm to touch than usual ?

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

man, what a journey ! Could not get ub400 4th point to work. It came off eventually, but I had no reballing tools. Felt lucky, cleaned and fluxed and got it back on with all LDO readings between 0.45 and 0.49 now!
2 caps came off, took an hour to get back, but made it!

All excited, but this is the situation now:
Upper ubc-c port only went on in one plug direction - then it shows 5.19 volt, but now 0.565 amps ( was much lower before, like 0.015-0.150).
Felt that UB300 became warm, so it seems sometimes goes wrong there.

Unplugged in time and still have same LDO reading on UB300 about, so it seems fine.
The other ports don´t do anything at the moment, neither direction.

I am wondering if I got further or not ?
I feel stuck again, although I am happy with the newly acquired understanding and skills.

Happy to get any tips to proceed. Thank you

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Yes, ub300 looks good now.

But ub400 needs some love.

Apply flux and reflow it. We want similar diode readings like ub300.

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Yes, could be a bad cap. What is the history of this CD3215 ? Was it replaced?

If yes, could also be soldering of the replacement part.

There is only 1 cap on this rail - see attached. Remove it and check the resistance to ground again for the same rail.

If there is still a short then the fault is in the soldering.

Proceed to apply flux on the top of this IC and hover over the CD3215 in circles till you cover the top surface with enough heat to melt the balls.

Use tweezers to gently nudge the IC - 'make it dance'. Then the IC will naturally bounce back into position - do this 2-3 times and the chip should settle onto the proper pads. Remove the heat. Allow it to cool and check the resistance of this rail again.

If the rail does return to normal (it should) then place the innocent cap back on, unless the cap is guilty.

I was a bit confused, but I think you mean CB306 because it is the LDOA rail?
CB305 resistance was very high.

I moved CB300 - it was replaced before - after that CB306 reading is better : 0.484 with diode mode on ldoa rail .

New diode readings:
ub300:
pp1v8_upc_ta_ldod : 0.443
pp3v3_upc_ta_ldo : 0.466
pp1v1_upc_ta_ldo_bmc : 0.471
pp1v8_upc_ta_ldoa : 0.487

ub400 after same treatment:
pp1v8_upc_tb_ldod : 0 - the cap cb405 is off
pp3v3_upc_tb_ldo : 0.567
pp1v1_upc_tb_ldo_bmc : 0.473
pp1v8_upc_tb_ldoa : 0L

Does this mean the UB400 is bad or anything else?
Not connected properly when measuring 0L ?
I will try to replace it again, or move again, this one needs a lot of heat to move and CB305 came off along the way .

Thanks for the help, seems UB300 is ok now?

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Yes, could be a bad cap. What is the history of this CD3215 ? Was it replaced?

If yes, could also be soldering of the replacement part.

There is only 1 cap on this rail - see attached. Remove it and check the resistance to ground again for the same rail.

If there is still a short then the fault is in the soldering.

Proceed to apply flux on the top of this IC and hover over the CD3215 in circles till you cover the top surface with enough heat to melt the balls.

Use tweezers to gently nudge the IC - 'make it dance'. Then the IC will naturally bounce back into position - do this 2-3 times and the chip should settle onto the proper pads. Remove the heat. Allow it to cool and check the resistance of this rail again.

If the rail does return to normal (it should) then place the innocent cap back on, unless the cap is guilty.

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

I think that both UB300 & UB400 have issues.

Configure your meter in resistance mode.

For UB300, measure & post the resistance to ground of the pp1v8_upc_ta_ldoa rail.

Hi, thank you for the quick reply!
I measure about 0.9 Ohm in the beginning and then it slowly drops to 0 in about 20 seconds.
Measuring the ground pin of that cap shows 0 first and then goes up a bit.

bad cap ? Measuring in bleep mode gives bleep, so looks like a short on it.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

ub300:
pp1v8_upc_ta_ldod : 0.453
pp3v3_upc_ta_ldo : 0.450
pp1v1_upc_ta_ldo_bmc : 0.475
pp1v8_upc_ta_ldoa : 0.000

ub400:
pp1v8_upc_tb_ldod : 0L ( so nothing? ) groundpin is 0.000
pp3v3_upc_tb_ldo : 0L again
pp1v1_upc_tb_ldo_bmc : 0.478
pp1v8_upc_tb_ldoa : 0L again

I think that both UB300 & UB400 have issues.

Configure your meter in resistance mode.

For UB300, measure & post the resistance to ground of the pp1v8_upc_ta_ldoa rail.