MacBook Pro A2251 - 820-01949 Voltage Drop and unkown issues.

[pb1911nt]

Hello forum,

I'm still relatively new to the world of electrical repairs.

I have a Macbook here that I can't figure out

When the battery is gone, the USB input consumption goes up to 20 V and 0.06A. But it breaks down after about 2-3 seconds and you can also hear a small ticking on the logic board. But I can't pinpoint it exactly.

I removed the logic board and took a few measurements.

But I can't really figure it out.

At first I thought the infamous CD chip was defective - but then of course you read more on the internet and suddenly it could be more or something else.

That's why I'm not so sure. I'm still new to repairs - and I'd like to slowly understand what's happening.


I also found the table online and I hope it can help ME? I entered the measurements but I didn't want to take 1800 measurements now?

Netname	Condition	Type	Value	measurement
1V8_SWCH_EN	Default	d	754	24,64
1V8_SWCH_SLEW	Default	d	OL	OL
ACT_GND	Default	d	0	0
AGND_P1V8PRIM	Default	d	0	0
ALL_SYS_PWRGD	Default	d	753	1.080
AP_PCIE_WAKE_L	Default	d	525	14.94
I2C_UPC_R_SCLM	Default	d	551	1,009
I2C_UPC_R_SDAM	Default	d	553	1,009
I2C_UPC_WR_SCL2	Default	d	485	fluctuates
I2C_UPC_WR_SDA2	Default	d	487	39 - 40
I2C_UPC_W_SCLM	Default	d	555	0,994
I2C_UPC_W_SDAM	Default	d	556	1
P1V05_VCCST_EN	Default	d	800	OL
P1V1REG_AGND	Default	d	0	0
P1V1REG_MODE	Default	d	539	28,82
P1V1REG_TRIP	Default	d	746	39,2
P1V1S3_PGOOD	Default	d	543	171.9
P1V1_BOOT_RC	Default	d	623	OL
P1V1_DRVH	Default	d	647	127
P1V1_DRVH_R	Default	d	650	127
P1V1_SNS	Default	d	167	50
P1V1_SNS_R	Default	d	158	40
P1V1_SW	Default	d	158	41
PD_P1V1_S3_EN	Default	d	516	990
PD_UPC_W_GPIO1	Default	d	691	100,9
PD_UPC_W_GPIO10	Default	d	712	100
PD_UPC_W_GPIO9	Default	d	711	100,9
PP0V6_S3	Default	d	200	635
PP0V6_S3	Default	v	600	0v
PP0V6_S3_REG_R	Default	d	200	fluctuates
PP0V82_SLPDDR	Default	d	52	31,1
PP0V82_SLPDDR	Default	v	820	0,825 - breaks down.	X.
PP0V8_SLPS2R	Default	d	224	fluctuates
PP0V9_SLPDDR	Default	d	70	48,1
PP0V9_SLPDDR	Default	v	900	0,9v
PP0V9_SSD0	Default	d	300	123
PP0V9_SSD0	Default	v	900	0,0v
PP0V9_SSD0_FB_DIS	Default	d	298	123,8
PP0V9_SSD0_S4E0_VDD_PLL	Default	d	307	123,7
PP0V9_SSD0_S4E1_VDD_PLL	Default	d	295	123,8
PP0V9_SSD0_S4E2_VDD_PLL	Default	d	312	123,7
PP0V9_SSD0_S4E3_VDD_PLL	Default	d	301	124,4
PP0V9_TBT_LVR_R	Default	d	516	28,51
PP0V9_TBT_LVR_T	Default	d	525	22-23
PP0V9_TBT_LVR_W	Default	d	517	29
PP0V9_TBT_LVR_W	Default	v	900	0,0v
PP0V9_TBT_LVR_X	Default	d	523	24-25
PP0V9_TBT_R_LC	Default	d	361	fluctuates
PP0V9_TBT_SVR_IND_R	Default	d	416	1,757
PP0V9_TBT_SVR_IND_R	Default	v	900	0,0v
PP0V9_TBT_SVR_IND_T	Default	d	397	1,637
PP0V9_TBT_SVR_IND_T	Default	v	900	0,0v
PP0V9_TBT_SVR_IND_W	Default	d	425	1,712
PP0V9_TBT_SVR_IND_W	Default	v	900	0,0v
PP0V9_TBT_SVR_IND_X	Default	d	400	0,922
PP0V9_TBT_SVR_IND_X	Default	v	900	0,0v
PP0V9_TBT_SVR_R	Default	d	416	1,34
PP0V9_TBT_SVR_R	Default	v	900	0,0v
PP0V9_TBT_SVR_T	Default	d	397	1,685
PP0V9_TBT_SVR_T	Default	v	900	0,0v
PP0V9_TBT_SVR_W	Default	d	425	1,721
PP0V9_TBT_SVR_W	Default	v	900	0,0v
PP0V9_TBT_SVR_X	Default	d	400	0,906
PP0V9_TBT_SVR_X	Default	v	900	0,0v
PP0V9_TBT_T_LC	Default	d	375	18,2
PP0V9_TBT_W_LC	Default	d	358	16,68
PP0V9_TBT_X_LC	Default	d	367	8,77
PP16V0_MESA	Default	d	648	fluctuates
PP16V0_MESA_FILT_CONN	Default	d	665	fluctuates
PP17V0_MOJAVE_LDOIN	Default	d	587	fluctuates
PP1P05_PCH_EXT	Default	d	514	0,785
PP1P05_PCH_EXT	Default	v	1.000	0,0v
PP1V05_PCH_OUT_FET	Default	d	192	125
PP1V05_PRIM_OUT_PCH	Default	d	193	128
PP1V05_S0SW_VCCSTG	Default	d	125	96,4
PP1V05_S0_CPU_VCCPLL	Default	d	193	128
PP1V05_S0_CPU_VCCST	Default	d	113	262
PP1V05_VCCSTG_OUT	Default	d	126	96,4
PP1V1_S0SW	Default	d	467	1,047
PP1V1_S3	Default	d	44	39,9
PP1V1_S3	Default	v	1.100	0
PP1V1_S3_CPU	Default	d	158	38
PP1V1_S3_REG_R	Default	d	44	38,2
PP1V1_S3_REG_R	Default	v	1.100	0V
PP1V1_SLPDDR	Default	d	330	2,262
PP1V1_SLPDDR_SOC_VDDIOPLLDDR_F	Default	d	330	2,262
PP1V1_SLPS2R	Default	d	241	2,04
PP1V1_SLPS2R	Default	v	1.100	1,103 breaks down	X.
PP1V24_S5_PCH_VCCDPHY	Default	d	369	19,05
PP1V25_SLPS2R_SMC_AVREF	Default	d	681	1,849
PP1V2_AWAKE	Default	d	522	fluctuates
PP1V2_AWAKE_SOC_PCIEPLL_F	Default	d	522	fluctuates
PP1V2_AWAKE_SOC_PLLCPU_F	Default	d	377	fluctuates
PP1V2_AWAKE_SOC_PLLSOC_F	Default	d	525	fluctuates
PP1V5_UPC_LDO_CORE_R	Default	d	505	fluctuates
PP1V5_UPC_LDO_CORE_R	Default	v	1.500	1,581
PP1V8_AWAKE	Default	d	402	29
PP1V8_AWAKE	Default	v	1.800	1,801
PP1V8_AWAKE_SOC_FMON_RC	Default	d	455	fluctuates
PP1V8_AWAKE_SOC_TSADC_RC	Default	d	402	fluctuates
PP1V8_SLPS2R	Default	d	359	38,41
PP1V8_SLPS2R	Default	v	1.800	1,802
PP20V_USBC_R_VBUS	Default	d	137	OL
PP20V_USBC_R_VBUS	Default	v	20.000	0
PP20V_USBC_W_VBUS	Default	d	135	OL
PP20V_USBC_W_VBUS	Default	v	20.000	0V
PP3V3_AWAKE	Default	d	639	8,65
PP3V3_G3H	Default	d	450	0
PP3V3_G3H	Default	v	3.300	3,339 breaks down	X.
PP3V3_G3HSW_DFR	Default	d	567	250
PP3V3_G3H_DFR	Default	d	450	OL
PP3V3_G3H_MESA_SW	Default	d	369	150
PP3V3_G3H_PMU_VDDMAIN	Default	d	450	fluctuates
PP3V3_G3H_PMU_VINRTC_R	Default	d	368	fluctuates
PP3V3_G3H_RSLOC	Default	d	369	fluctuates
PP3V3_G3H_RTC	Default	d	369	OL
PP3V3_G3H_RTC	Default	v	3.300	3,392
PP3V3_G3H_RTC_MESA	Default	d	369	fluctuates
PP3V3_G3H_RTC_REG_R	Default	d	388	fluctuates
PP3V3_G3H_RTC_REG_R	Default	v	3.300	3,394 stable
PP3V3_G3H_SSD0	Default	d	369	fluctuates
PP3V3_G3H_SSD0	Default	v	3.300	3,393
PP3V3_G3S	Default	d	338	4,2
PP3V3_S5	Default	d	356	fluctuates
PP3V3_S5	Default	v	3.300	0
PP3V3_UPC_R_VOUTLV	Default	d	538	100
PP3V3_UPC_T_LDO	Default	d	500	548,8
PP3V3_UPC_T_LDO	Default	v	3.300	3,388 - stable
PP3V3_UPC_W_LDO	Default	d	498	fluctuates
PP3V3_UPC_W_LDO	Default	v	3.300	3,393
PP3V3_UPC_W_VOUTLV	Default	d	537	100,3
PP3V3_UPC_X_LDO	Default	d	510	fluctuates
PP3V3_UPC_X_LDO	Default	v	3.300	3,388
PP5V_G3S	Default	d	433	411
PP5V_G3S	Default	v	5.000	0v
PP5V_S4_WR_USBC	Default	d	511	16,7
PP5V_S4_WR_USBC	Default	v	5.000	0
PP5V_VDD2_V5IN	Default	d	424	407
PPBUS_G3H	Default	d	510	fluctuates
PPBUS_G3H	Default	v	13.100	12,32
PPBUS_G3H_SPKRAMP_LEFT	Default	d	510	OL
PPBUS_G3H_SPKRAMP_LEFT	Default	v	12.000	12,32
PPBUS_G3H_SSD0	Default	d	510	OL
PPBUS_G3H_SSD0	Default	v	13.100	12,32
PPBUS_HS_CPU	Default	d	510	OL
PPBUS_HS_CPU	Default	v	13.100	12,32
PPDCIN_G3H	Default	d	550	fluctuates
PPDCIN_G3H	Default	v	20.000	20,52
PPDCIN_G3H_CHGR	Default	d	562	fluctuates
PPDCIN_G3H_CHGR	Default	v	20.000	20,52
PPHV_INT_G3H_R	Default	d	550	fluctuates
PPHV_INT_G3H_R	Default	v	20.000	20,52
PPHV_INT_G3H_T	Default	d	550	fluctuates
PPHV_INT_G3H_T	Default	v	20.000	20,52
PPHV_INT_G3H_W	Default	d	549	fluctuates
PPHV_INT_G3H_W	Default	v	20.000	20,53
PPVCCIN_AUX_PCH_PRIM	Default	d	380	154
PPVCCIN_AUX_PCH_PRIM	Default	v	1.800	0
PPVCCIN_S0_CPU	Default	d	90	25,5
PPVCCIN_S0_CPU	Default	r	80.000R	?
PPVCCIN_S0_CPU	Default	t	start 1,8v -0v 1sec - 1,6v.	0
PPVCCIN_S0_CPU	Default	v	1.500	0
PPVTT_VTTREF	Default	d	489	14,57
PVDD2_EN_R	Default	d	558	212
PVDDQ_EN	Default	d	558	212
SPARE_UPC_R_DBG	Default	d	625	100,4
SPARE_UPC_W_DBG	Default	d	640	98,9
TBT_W_FORCE_PWR	Default	d	586	OL
UPC_R_OSC_R	Default	d	465	14,99
UPC_R_RESET	Default	d	588	91,3
UPC_SS_R	Default	d	579	4,8
UPC_WR_5V_EN	Default	d	627	101,3
UPC_WR_UART_RX	Default	d	553	1,009
UPC_WR_UART_TX	Default	d	553	1,007
UPC_W_FAULT_L	Default	d	687	10,06
UPC_W_RESET	Default	d	590	92
UPC_X_VRET_R	Default	d	0	0
UPC_X_VRET_W	Default	d	0	0
USBC_AUXLSX_N_R	Default	d	712	12,6
USBC_AUXLSX_P_R	Default	d	701	12,7
USB_UPC_1_N_R	Default	d	432	1,55
USB_UPC_1_P_R	Default	d	431	1,56