MacBook Pro 2019 A2159 (2-port) wont boot

[2informaticos]

First of all, welcome to the forum!

Work with the MLB alone on the desk, using original 61/87W charger.
Do not connect anything, apart of charger (no battery).
Just check the voltage on big coils.

 

[Eniaro]

Thank you.
I don't repair Macs that often but there has been an uptick lately and most of my repairs have been exploded caps so this level of troubleshooting is new for me.
I have been using the Apple 87W, (I included the dock information in case it provides any information that could be helpful)

All coils measure 0.01v
To make sure I'm doing the right thing I included a photo

 

[2informaticos]

If USB-C inputs switch to 20V, then PPBUS_G3H and 3V3_G3H_RTC are both present.
Check their exact voltage anyway.
Also check all G3S and SSD voltages.

 

[Eniaro]

@ the USB-C voltage goes from 5v to 20v like normal

PPBUS_G3H: 12.58V (measured at @ CD761)
PP3V3_G3H_RTC: 3.312V (measured the same everywhere)

I'm not quite following when you say all G3S and SSD voltages...

I2C_SSD_SCL: 1.797V (measured at @R2523)
I2C_SSD_SDA: 1.797V (measured at @ @R5230)
P3V3G3S_SS: 2.889V (measured at @ @U8200 & C8200)

Edit: while testing everything in Board Viewer that lists G3S
PP5V_G3S_VCCIOPVCC: C8143 appears to be shorted

Edit 2 can I use: Schematics says 10UF 20% 10V X5R Cerm 0402-7, on hand, I have 0402 10uF 6.3V 20% X5R can I use it for testing?

 

[2informaticos]

Good enough for test.

 

[Eniaro]

Replacing C18143 with 0402 10UF 6.3V
PP5V_G3S_VCCIOPVCC to measure 5.102V
P3V3G3S_SS
The USB-C meter is now 20.14V and 0.25A before it was 0.00 amp
CPU gets warm at about 40°C

Does this indicate its back to life being a noob it would be a pain to reassemble and it still doesn't work

 

[2informaticos]

Check voltage on the big coils from CPU area.
You can also connect an external monitor for test.
An USB-C test tool is also helpful.

 

[Eniaro]

USB-C 87W: 20.16V 0.28A when CPU gets warm. 20.16V 0.00A when CPU does not get warm
USB-C monitor cycles 5v > 20v >off > 5v> 20V > off> repeat

 

[2informaticos]

When CPU gets hot, you should have voltage on more coils near CPU; apart of RAM's one.
This board is not complicated to put back in case and test...

 

[Eniaro]

So I put it back together, the system has improved, however, there is no display, and the USB-C monitor (with USB-C meter) shows 5v then 20v then off the monitor sees MacBook for a few seconds then off... endless loop.

with just the 87w charger there's no 5v>20V loop

also, the fan spins as well

 

[2informaticos]

Is it recognized in DFU mode?

 

[Eniaro]

Took some serious tries to get it to DFU mode but it did, I am not sure if it's a 1d10t (me) issue or the system itself
I tried "revive" & "restore", during the process, the display remained blank eventually my host mbp displayed a lock... but the A2159 still has nothing on screen

Edit 2: I just noticed the 5>20V endless loop connected to the USB-C monitor only occurs when the battery is disconnected but when the battery is connected it cycles and then maintains 0.95 amperage

 

[2informaticos]

Check diode mode to ground on all secondary power rails (big coils).
BTW, good enough to check ONLY one pin of the coils.

 

[Eniaro]

my noobness is about to show here...
Red to ground and Black to coil pin?
Am I checking for open or short?

 

[2informaticos]

Ideally, compare with good board.
Short, or open, both are bad; we suspect short somewhere.

Reference table exists on Internet.

OpenBoardData Project

 

[Eniaro]

I didn't get to inspect the rails yet,
I noticed L2950 had a crack in it and tested it for short, and thinking it was a cap, removed it. While removing it, it completely disintegrated. I don't think this was the issue but I have to suspend troubleshooting until I find a replacement. The only "donor" board I have is an 820-00430 which was given to me I don't know if it has parts I can use

Edit does anyone know where I can find L2590 (0.68UH-20%-6.1A-0.020OHM 1210)

Edit 2: will this work?
TDK TFM322512ALMAR68MTAA

 

[2informaticos]

The board can boot without that coil.
You have time to find a replacement coil, once you've got the board booted first.

 

[Eniaro]

Component	Type	OBD P Value	Tested Value	Testpoint (comments)
PP3V3_G3S	d	0.365	0.358
PP3V3_G3S_KBD	d	0.368	0.360
PP3V3_G3S_TPAD	d	0.3336	0.357
PP3V3_G3S_WLANBT	d	0.365	0.360
PP5V_G3S	d	0.426	0.435
PP5V_G3S_ALSCAM	d	0.426	0.440
PP5V_G3S_CPUREG_MISC	d	0.426	0.441
PP5V_G3S_DFR_FILT	d	0.4195	0.442
PP5V_G3S_EDRAMPVCC	d	0.427	0.442
PP5V_G3S_EDRAMVCC	d	0.427	0.442
PP5V_G3S_FAN_CONN	d	0.4154	0.440
PP5V_G3S_KBD	d	0.426	0.440
PP5V_G3S_TPAD	d	0.423	0.440
PP5V_G3S_TPAD_CONN	d	0.4147	0.438
PP5V_G3S_VCCIOPVCC	d	0.431	0.509
PP5V_G3S_VCCIOVCC	d	0.429	0.534
P5VG3S_COMP1	d	0.75	0.763
P5VG3S_COMP1_R	d	OL	2.628	R7675 C7679
P5VG3S_CS1_L_N	d	0.422	0.439
P5VG3S_CS1_L_P	d	0.422	0.038
P5VG3S_CSP1	d	1.264	1.036
P5VG3S_DRVH	d	0.991	0.990
P5VG3S_DRVH_R	d	OL	0.989	R7666 (Short?)
P5VG3S_DRVL	d	0.565	0.560
P5VG3S_DRVL_R	d	0.566	0.559
P5VG3S_EN	d	0.584	0.625
P5VG3S_EN_DLY	d	0.528	0.560
P5VG3S_EN_R	d	0.585	0.626
P5VG3S_PGOOD	d	0.584	0.617
P5VG3S_SNUBR	d	OL	OL
P5VG3S_SW	d	0.425	0.438
P5VG3S_VBST	d	0.642	0.614
P5VG3S_VBST_R	d	0.636	0.643
P5VG3S_VFB1	d	0.586	0.629
P5VG3S_VFB1_R	d	0.422	0.438
P5VG3S_VFB1_R2	d	0.433	0.453
P5VG3S_VFB1_RR	d	OL	2.522
P5VG3S_VSW	d	0.416	0.437
L8410	d		0.880
L7420	d	0.007	0.080 0.007
L7210	d	0.007	0.090 0.007
L7220	d	0.007	0.090 0.007
L7270	d	0.051	0.051
L8102	d	0.144	0.144
L8100	d	0.302	0.302
L7030	d	0.480	0.480
L7690	d	0.429	0.429
L7670	d	0.438	0.438
L8410	d	0.880	0.880
L9081	d	0.354	0.354
L9080	d	0.353	0.353
L9021	d		0.414
L9020	d		0.415
L7410	d		0.090
L9030	d		0.333

I didn't find the coil values on OpenBoardData Project :\

P5VG3S_DRVH_R @ R7666 seems to have a short

 

[2informaticos]

Oh god, did you test all these???
I said to check power rails; put some logic on your job.
Also don't waste time checking the same line in 10 points, just because it changes the name.

"I didn't find the coil values on OpenBoardData Project"
Big coils have line names associated also.

Board still cycles testing alone on the desk (no monitor connected)?