MacBook Pro 15" 2017 A1707 Touchbar No power

[MobileXT]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Try check on pin 2 R6923 for shorted.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Yes, as per above.

What is the resistance to ground on pin 2 of the removed zero ohm resistor?

If the value is low, then you have probably have a bad cap on this rail.

Please post the value.

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Left the shop, will post value first thing tomorrow!

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

so further testing on pin 2 i am getting a reading and it keeps dropping.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

What is the reading of the value?

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

ok don't think I am dumb here. But I have it set to Resistance. But should i have the power plugged in for this or not? Because I get two readings doing it. Sounds dumb I know.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Resistance and Diode values can only be measured with the unit powered OFF.

Kill the power and black probe to ground; RED probe onto pin 2 of this resistor pad that has been removed.

Wish to check the resistance along this rail to see if it is too low. Often too low of a reading implies a short circuit - either external due to corrosion or internal from some bad cap. Tantalum (black polarized ones) are usually the bad ones over time.

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Figures thanks
It starts at 40.00 M OHMS and drop and keeps dropping.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

That is a high reading and that is fine. If you bring back the zero ohm resistor, this line starts to fluctuate or is it steady?

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

When we bring back the resistor the board starts to turn off and on on the USB C meter. It basically starts the process over looping. It stopped when the resistor was removed

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Also if the resistor is brought back the line will fluctuate and loop.

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Which CD32xx USB controllers have been replaced?

When you attach a suitable power adapter, does the voltage ever negotiate to 20V?

Are you confident of your CD3215 replacement exercise?

From my (limited) knowledge, each CD3215 controller is required to be operational and has to ping back to the SMC controller over the I2C bus (SDA / SCL lines).

That is, the SMC controller will systematically communicate with each local controller over the I2C bus using their unique address and the respective controller is required to ping back a valid response.

Perhaps this communication is broken with one of more of the CD3215 controller. Or it is possible that the communication is ok and then the power negotiation is escalated to 20V and the unit powers down due to an excessive current draw and starts this looping cycle.

Have not personally attempted it but any chance you have a low cost USB based logic analyzer? They are < $20 USD on Amazon and < $5 USD on Aliexpress.

Using such a tool, you can solder 3 wires onto the macbook and snoop on the I2C bus traffic to monitor what the SMC is sending / receiving from each I2C slave.

Here is what I am referencing:

https://www.aliexpress.com/item/4000...archweb201603_

There are many others at lower costs.

You just need to find one that is available in the USA at a fair price.

We may be going down a rabbit hole here but am a strong believer that you need to the proper tool to diagnose such rather high tech devices.

Perhaps a better suggestion is to first check the wikipedia link:

https://logi.wiki/index.php/CD3215_Bootup_Sequence

and confirm the diode readings for the D+ / D- lines for each CD3215 port.

1) Place your multimeter in DIODE mode.
2) Turn OFF all power to this logic board.
3) RED (yes RED) meter lead to GROUND.
4) BLACK (yes BLACK) meter lead to the D+ line to a CD3215 port.

What is the reading?

5) BLACK (yes BLACK) meter lead to the D- line to a CD3215 port.

What is the reading?


Repeat the above steps (4 & 5) for each USB Type C port.

What are the readings for each probing?


If the readings are off then that local CD3215 controller may need to be replaced.

Please post your updates.

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

The board never goes to 20V. It just gets to 5.20v then cycles off and repeats. I have replaced two CD32 chips, I guess I need to replace the other two as well. I have stenciled the other two and they came out great, Ill just replace those other two and reball them and put them back on the board and see what happens.
lol it just sucks because these CD32 are a bitch since there is 4 of them you have to do lol. Also I will look into buying that stuff as well. Ill keep you posted. This is just a board laying around. We threw it in our Crest Ultrasonic cleaner and it cleaned up very well, and still having issues so now we know its def in this area for sure. So far visually under the scope there are no lifted pads (THANK GOD). This may be a 2TB board with the max GPU upgrade and we really want to get this working because this is a very pricey board we want repaired. Other boards are pretty easy, but once we get to this level it starts getting down to problem solving again, ALSO thanks for your help mon2

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

No worries. We are on similar paths. Have a painful A1706 that needs more love and trying to avoid it. Doing so without a microscope till the CNY.

Do post your DIODE readings as they may assist us in debugging this logic board.

[Stephen]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power



This is what I am working with atm. We are still adding more repair equipment to our office.

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

Try check on pin 2 R6923 for shorted.

That is a high reading and that is fine. If you bring back the zero ohm resistor, this line starts to fluctuate or is it steady?

Hi, I hope it's ok to join the thread, I have a very similar problem.
Short background: MacBook Pro 15 late 2016 A1707 820-00281-A board. I have boardview and schematics, it's one of my first repairs.
Cleaned board with toothbrush and WD-40 and some place alcohol.

Before cleaning the backlight seemed broken, but also the non-backlit screen got dimmer - otherwise it chimed and booted and worked with external screen.
After clean: no more chime - fans on - off /on loop it seems.

I read this whole tread and tried measuring.
I had a steady 3.4 V on the 0 Ohm R6923 on both pins, but only after plugging in the USB charger (Apple, 87W) and sometimes for a few seconds, sometimes longer (minutes).
Then it goes to 0 V for a while and if I measure a bit later it is sometimes -0.4 V and then 0.

I don't have a USB amp meter yet, but I had a steady 20.1 V on the fuse shortly after the USB powerplug, so it seems I'm good on the USB chips part?
Actually while writing this I also only have 5V on the fuse that was 19 before, seems things are deteriorating .... but also that I am in the same situation now?

I'm confused about S0 - I understood from reading that 20V means S0 is reached so those should be measured.

but it seems I suddenly have a short on pin 2 of R6923 using a Fluke in bleep mode, it bleeps.. In diode mode about 1.5 Ohm.

How should I proceed now, take of this resistor and measure both points in diode mode?
Thanks, hope I'm not hijacking the thread, thought we might all get to a working end result

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

hi @openminded. it is an all age virtual group party. everyone is welcome.

1) lose the wd40 - not sure I would consider that for anything electronic. also concerned about it being flammable around heat sources.

pure alcohol is fine and recommended - ideally sourced from an electronics vendor but should be ok to get medical grade from a pharmacy in a pinch. higher purity is always recommended.

2) proceed with caution - if in doubt - DO NOT power on the board. The A1706/A1707 or newer are very tiny and dainty PCBs. Not sure about you but the parts are quite small and unless you have a microscope, almost impossible to work with once the parts are removed or damaged.

We have a full SMT line in-house and prefer to stay with 0402 parts for our designs. Have worked with 01005 placements just to exercise our machinery but when Apple sprinkles these all over their PCBs, have to believe they want to torture the repair shops.

3) Remove R6923 for now. Be sure that all power is OFF to the logic board. Place your meter in resistance mode. Then black probe of meter to ground on the board (metal shields are good). Red probe onto the pin # 2 of where the R6923 used to be. You are testing to check the resistance to ground for the voltage rail. If the resistance is too low, then there is a shorted cap on this rail and causing the poor, low current regulator to shut off to protect itself.

If it is safe to do so with this logic board, power up and place your meter in voltage mode -> check the voltage on pin #1 of where R6923 used to be.

Is this voltage regulator still working?

Post your values for each requested points of interest.

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

hi, thanks for the quick reply .

Small addition : I looked at https://www.youtube.com/watch?v=US-Iia5Er7E which was quite helpful.
I might have a short on pin 2 of D6902, so maybe indeed a bad cap.

I don't understand what you mean with all the numbers at the moment, but yeah, things are really small and I am not too well equipped to work with that - magnifying glass, no microscope .
I have hot air / SMD station so I am going to try the removal of the resistor, measure and post the values.

Thanks once again!

[mon2]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

To test the diode you have referenced, note that this is dual diode inside a single package. This package is called sot-23 in the industry.

Fancy way of naming this 3 legged device.

The part, when it works correctly, will take in 2 power rails and allow the higher voltage to pass through to pin #3 (common cathode) without impacting the other voltage rail.

The diode does not allow for the voltage on pin #3 to reverse feed into pin #1 or pin #2.

To test this dual diode, remove all power on this logic board.

Set up your meter into diode mode and follow this webpage:

https://www.fluke.com/en-ca/learn/bl...to-test-diodes

Summary, red probe on pin #1 of the diode (anode #1) and black lead on pin #3. Reading should be about 0.5 to 0.6 volts if ok.

Repeat with pin #2 and #3.

Setup your meter to voltage mode.

Power up.

Check voltage on pin #1...then pin #3. The readings should be close to each other. Confirm.

Power down the board.

Pin #2 is the voltage fed from your battery. Any voltage? If not, battery could be depleted. Pin #3 and pin #2 should be close to each other but only if power is off.

Pin #1 of the diode is powered by your external adapter as the power source and then a local buck (step down) converter.

Post the values for all 3 pins of this dual diode.

[openminded]

Re: MacBook Pro 15" 2017 A1707 Touchbar No power

hi, thank you for all the explaning, that helps a lot for a beginner like me .
The WD-40 I will keep aside, it's mostly to get rid of fluid. I'm in Sweden now so can't buy alcohol like that so I am careful with what I have .

aha, so 0402 is the small stuff, it's small indeed! and the 10015 capacitor too, aha.

I got the resistor off, pin 1 has high resistance, pin two has:
- about 153 Ohm with power on
- about 2 Ohm with power off
clear short - but where?

I measured no voltage on pin 1 with power on it - that is when the charger gave 5.1 V - it does not go to 19V (anymore)

The diode measurements (using 1,2,3 as from boardview schematics, 3 being top):

Summary, red probe on pin #1 of the diode (anode #1) and black lead on pin #3. Reading should be about 0.5 to 0.6 volts if ok.
- this reads 0.2 V - black on one , red on 3 gives 2,1V

Repeat with pin #2 and #3.
- black on 2, red on 3 gives 1.99 V , vice versa 0.2V

Setup your meter to voltage mode.

Power up.

Check voltage on pin #1...then pin #3. The readings should be close to each other. Confirm.
- the voltage are 0 on all pins (actually 0.002 on pin 1, power on charge 5.1V)

Power down the board.

Pin #2 is the voltage fed from your battery. Any voltage? If not, battery could be depleted. Pin #3 and pin #2 should be close to each other but only if power is off.

Pin #1 of the diode is powered by your external adapter as the power source and then a local buck (step down) converter.

Post the values for all 3 pins of this dual diode.

- My board is completely out so I have no battery attached. do the values suffice?
I have like 8 Ohm on pin 2 of the diode, with resistor still off all the time. that smells like a short too?

Thanks for the help and happy to learn what a next good stap to make is!