Macbook Pro A1706 doesn't power on

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

Could it be something with thunderbolt RAMs ?

I would not suspect the thunderbolt Rams. I would still suspect the power circuit because if i am not mistaken the thunderbolt RAMs defect might affect the powering on but not the voltage value. It should show as around 20v on the metre.

So i would still suspect either one of the CD3215'S or a short on the 20v somewhere on the board which forces the CD3215'S to stuck on the 5v.

Take a look on this video...

https://youtu.be/6yVUEXRonHc

[miro.manchev]

Re: Macbook Pro A1706 doesn't power on

I would not suspect the thunderbolt Rams. I would still suspect the power circuit because if i am not mistaken the thunderbolt RAMs defect might affect the powering on but not the voltage value. It should show as around 20v on the metre.

So i would still suspect either one of the CD3215'S or a short on the 20v somewhere on the board which forces the CD3215'S to stuck on the 5v.

Take a look on this video...

https://youtu.be/6yVUEXRonHc

Yeah, I've watched this video a couple of times, that's why I've checked the diode. I will make more measures and check the 20V line

[Stevedb]

Re: Macbook Pro A1706 doesn't power on

Hi

@wheelcup @miro machev

I think you got the same problem has louis rosmann has

Watch this

https://youtu.be/vXAK2l1oMZM

Regards Steve

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

Hi

@wheelcup @miro machev

I think you got the same problem has louis rosmann has

Watch this

https://youtu.be/vXAK2l1oMZM

Regards Steve

Thanks for the video.
I was not expecting a faulty thunderbolt Ram would cuz the power to cut on 5v. Never. So this was unique. Thanks again.

I would still suspect a SHORT may be on the TB ram chip but again that was odd.

Although the case here is not on one hole side. It is only one port that stays on 5v with out reseting itself. So might be the line that connect the thounderbolt RAM to the CD3215 on that side.

[miro.manchev]

Re: Macbook Pro A1706 doesn't power on

So I've meassured everything arround U6903(MAX77596). This is the result:
- pin1 P3V3G3H_VBST 7.8V
- pin2 PPVIN_G3H_P3VG3H 4.85V
- pin3 P3V3G3H_LX. 3,43V
- pin8 P3V3G3H_BIAS 4.85V
- pin9 P3V3G3H_FB. 1.01V
- pin10 PM_EN_P3V3_G3H. 5.01V

I've put a video where measurung the 20V line caps arround the CD3215s. One of them stays on arround 10kOhm and the rest 3 of them are rippling a lot. I suspect the one, which is stable is on the port that stays on 5V constantly whithout bootlooping.

Meassuring C3101 and C3201 arround CD3215 I've got 533ohm, which seems too low. This is meassured from ground shield to the PP20V_USBC_XA(XB)_UBUS, but meassuring on both sides of the caps, you can see on the video.
https://www.youtube.com/watch?v=LLfnbsotSaw

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

So I've meassured everything arround U6903(MAX77596). This is the result:
- pin1 P3V3G3H_VBST 7.8V
- pin2 PPVIN_G3H_P3VG3H 4.85V
- pin3 P3V3G3H_LX. 3,43V
- pin8 P3V3G3H_BIAS 4.85V
- pin9 P3V3G3H_FB. 1.01V
- pin10 PM_EN_P3V3_G3H. 5.01V

I've put a video where measurung the 20V line caps arround the CD3215s. One of them stays on arround 10kOhm and the rest 3 of them are rippling a lot. I suspect the one, which is stable is on the port that stays on 5V constantly whithout bootlooping.

Meassuring C3101 and C3201 arround CD3215 I've got 533ohm, which seems too low. This is meassured from ground shield to the PP20V_USBC_XA(XB)_UBUS, but meassuring on both sides of the caps, you can see on the video.
https://www.youtube.com/watch?v=LLfnbsotSaw

The 533ohm is low for the 20v line. Can you compare it to the other side ... i meant what is the resistance on CB301 AND CB401..?

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

So I've meassured everything arround U6903(MAX77596). This is the result:
- pin1 P3V3G3H_VBST 7.8V
- pin2 PPVIN_G3H_P3VG3H 4.85V
- pin3 P3V3G3H_LX. 3,43V
- pin8 P3V3G3H_BIAS 4.85V
- pin9 P3V3G3H_FB. 1.01V
- pin10 PM_EN_P3V3_G3H. 5.01V

I've put a video where measurung the 20V line caps arround the CD3215s. One of them stays on arround 10kOhm and the rest 3 of them are rippling a lot. I suspect the one, which is stable is on the port that stays on 5V constantly whithout bootlooping.

Meassuring C3101 and C3201 arround CD3215 I've got 533ohm, which seems too low. This is meassured from ground shield to the PP20V_USBC_XA(XB)_UBUS, but meassuring on both sides of the caps, you can see on the video.
https://www.youtube.com/watch?v=LLfnbsotSaw

I got an apple a1706 today. Different issue, but took these measures for you on the 20v line.

[miro.manchev]

Re: Macbook Pro A1706 doesn't power on

I got an apple a1706 today. Different issue, but took these measures for you on the 20v line.

Thanks, I will compare tomorrow and measure. Will let you know asap.

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

Thanks, I will compare tomorrow and measure. Will let you know asap.

Just remembee. These are diode mode measures. Red probe on GND and black probe on component pin.

[miro.manchev]

Re: Macbook Pro A1706 doesn't power on

So I did the diode meassurements and put my readings next to yours. Also checked those 4 20vc caps: CB301, CB401, C3101 and C3201. The 4 of them behave the same and it's like this:
- black probe on GND gives non stable readings, jumping from k to mOhms and can't get any stable data. Only once I was able to get about 4mOhs and rising on CB301. Not sure if there was a contact issue with my probes
- red probe on GND gives readings about 533Ohm on all of the caps

No sure, but I will get a better multimeter and check again.

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

So I did the diode meassurements and put my readings next to yours. Also checked those 4 20vc caps: CB301, CB401, C3101 and C3201. The 4 of them behave the same and it's like this:
- black probe on GND gives non stable readings, jumping from k to mOhms and can't get any stable data. Only once I was able to get about 4mOhs and rising on CB301. Not sure if there was a contact issue with my probes
- red probe on GND gives readings about 533Ohm on all of the caps

No sure, but I will get a better multimeter and check again.

The readings are normal. And yes it is normal to flactuate when black probe is on GND. I do not suspect those line.

I would suggest to check resistors. Supposing that the CD3215 is ok and soldered correctly.

I would check the resistors connecting thunderbolt ram with the CD3215. The one that you replaced.

Check these 2 groups of resistors.
3.3k group
RB090
RB091
RB092
RB093

15 ohm group
RB280
RB281
RB282
RB283
RB284
RB285

Those are all sourrounding the thunderbolt ram chip.
The given specific resistors numbers are belonging to one side of the board. It might not be the side you are interested in. If not, kindely check relative resistors on the other side (where you replaced the CD3215.

[miro.manchev]

Re: Macbook Pro A1706 doesn't power on

The readings are normal. And yes it is normal to flactuate when black probe is on GND. I do not suspect those line.

I would suggest to check resistors. Supposing that the CD3215 is ok and soldered correctly.

I would check the resistors connecting thunderbolt ram with the CD3215. The one that you replaced.

Check these 2 groups of resistors.
3.3k group
RB090
RB091
RB092
RB093

15 ohm group
RB280
RB281
RB282
RB283
RB284
RB285

Those are all sourrounding the thunderbolt ram chip.
The given specific resistors numbers are belonging to one side of the board. It might not be the side you are interested in. If not, kindely check relative resistors on the other side (where you replaced the CD3215.

I've checked both resistor groups for both sides. All seems fine readings for 3.3k are about ~3.27k and for 15.2 are from 14.8-15.4 ohms.

I cannot be sure that CD3215 was soldered correctly. I'm gonna buy one more chip and resolder it on another place. Any other ideas till the chip come?

[Weelcup]

Re: Macbook Pro A1706 doesn't power on

I've checked both resistor groups for both sides. All seems fine readings for 3.3k are about ~3.27k and for 15.2 are from 14.8-15.4 ohms.

I cannot be sure that CD3215 was soldered correctly. I'm gonna buy one more chip and resolder it on another place. Any other ideas till the chip come?

I would suggest the same thing at this point.
Hoping the new chip to fix the issue..

All the best