MacBook Pro 2019 A2159 (2-port) wont boot

Eniaro

New member
Hi Noob here kinda I have a MacBook Pro 2019 A2159 (2-port) wont boot

Trackpad clicks.

Plugging in a genuine USB-C charger and any other charger = 20V and charges all the way.

Plugging in a Dell USB-C dock (WD15 docking station: is capable of outputting 19.5V/3.34A)
or
Dell USB-C monitor causes the voltage to cycle endlessly between 5V and 19V (Dell P2419HC: has built-in power delivery, capable of outputting 20V/3.25A)

The Caps Lock button doesn't illuminate.

Holding the power button (fingerprint scanner) for 10 seconds stops the trackpad clicking temporarily, but it starts clicking again after 3 seconds.

If I open the lid slightly, the trackpad stops clicking.

The keyboard backlight is not working.

The Touch Bar is not displaying anything.

Resetting the SMC and PRAM, as well as fully discharging the battery, has not resolved the issue.

I've replaced the display. ( Original had a small crack on lower right corner)

I've even bench-tested the logic board with nothing attached, plugging in a genuine USB-C charger and any other charger = 20V but the same 5/19V loop cycle when connected to a USB-C hub or monitor.

No physical components are visually damaged


I'm at a loss as to where to start troubleshooting this problem any help will be appreciated
 

2informaticos

Administrator
Staff member
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

New member
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

PXL_20241218_230905247.MP@0.75x.jpg
 

2informaticos

Administrator
Staff member
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

New member
@ 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?
 
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Eniaro

New member
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

Administrator
Staff member
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

New member
PXL_20241218_230905247.MP-Recovered@0.75x.jpg

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

Administrator
Staff member
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

New member
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
 

Eniaro

New member
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
 
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2informaticos

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

Eniaro

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

Eniaro

New member
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
 
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2informaticos

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

Eniaro

New member
ComponentTypeOBD P ValueTested ValueTestpoint (comments)
PP3V3_G3Sd0.3650.358
PP3V3_G3S_KBDd0.3680.360
PP3V3_G3S_TPADd0.33360.357
PP3V3_G3S_WLANBTd0.3650.360
PP5V_G3Sd0.4260.435
PP5V_G3S_ALSCAMd0.4260.440
PP5V_G3S_CPUREG_MISCd0.4260.441
PP5V_G3S_DFR_FILTd0.41950.442
PP5V_G3S_EDRAMPVCCd0.4270.442
PP5V_G3S_EDRAMVCCd0.4270.442
PP5V_G3S_FAN_CONNd0.41540.440
PP5V_G3S_KBDd0.4260.440
PP5V_G3S_TPADd0.4230.440
PP5V_G3S_TPAD_CONNd0.41470.438
PP5V_G3S_VCCIOPVCCd0.4310.509
PP5V_G3S_VCCIOVCCd0.4290.534
P5VG3S_COMP1d0.750.763
P5VG3S_COMP1_RdOL2.628R7675 C7679
P5VG3S_CS1_L_Nd0.4220.439
P5VG3S_CS1_L_Pd0.4220.038
P5VG3S_CSP1d1.2641.036
P5VG3S_DRVHd0.9910.990
P5VG3S_DRVH_RdOL0.989R7666 (Short?)
P5VG3S_DRVLd0.5650.560
P5VG3S_DRVL_Rd0.5660.559
P5VG3S_ENd0.5840.625
P5VG3S_EN_DLYd0.5280.560
P5VG3S_EN_Rd0.5850.626
P5VG3S_PGOODd0.5840.617
P5VG3S_SNUBRdOLOL
P5VG3S_SWd0.4250.438
P5VG3S_VBSTd0.6420.614
P5VG3S_VBST_Rd0.6360.643
P5VG3S_VFB1d0.5860.629
P5VG3S_VFB1_Rd0.4220.438
P5VG3S_VFB1_R2d0.4330.453
P5VG3S_VFB1_RRdOL2.522
P5VG3S_VSWd0.4160.437
L8410d0.880
L7420d0.0070.080 0.007
L7210d0.0070.090 0.007
L7220d0.0070.090 0.007
L7270d0.0510.051
L8102d0.1440.144
L8100d0.3020.302
L7030d0.4800.480
L7690d0.4290.429
L7670d0.4380.438
L8410d0.8800.880
L9081d0.3540.354
L9080d0.3530.353
L9021d0.414
L9020d0.415
L7410d0.090
L9030d0.333

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

P5VG3S_DRVH_R @ R7666 seems to have a short
 
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2informaticos

Administrator
Staff member
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)?
 
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