Lenovo IdeaPad 5 15ALC05 NM-D701 black Screen

[master3112]

Hello everyone,

I have a Lenovo IdeaPad 5 15ALC05 NM-D701. When I press the power button, the fan comes on, the power button flashes but the screen remains black. The device has a current consumption of 0.7A. I only have a BoardWiever for the device and no schematic. I have already tried to rewrite the BIOS, but the behavior is the same.
I have checked all voltages and everything fits:
PU1901 LV5028RPC - works
PL6202 -5.08V
PL6201 - 3.32V
PL300 - 0.77V
PL2101- 1.8V
PL1901 - 0.77V
PL1902 - 1.8V
PL1903 - 1.21V
PL5601 - 1.10V
PL5602 - 1.10V
PL5603 - 1.10V
PL5604 - 0.77V
However, I have found a anomalous. When the device turns on and I look at the mainboard with a thermal imaging camera, the inductors get warm. One area of the CPU is supplied with 1.1V via PL5601, PL5602, PL5603 and another with 0.77V via PL5604. The PL5601-PL5693 get warm but the PL5604 is completely cold and there is no current flowing through it. Is this responsible for the GPU area and therefore no picture? The CPU power controller for PU560152 (RT3663BR) seems to be fine because the voltages are present. Does anyone have an idea?

[rogfanther]

Have you tried with external display ?

[master3112]

I have connected an external monitor via HDMI. I have also replaced the flex cable to the screen and the screen with a new one. No picture. I have also examined the power IC UT3 (RTS5457V-GR) to see what it controls. This goes via PIN 2 to the CPU and via PIN 37 to the QC8 and this supplies 1V8 to the CPU. I will investigate this area in more detail. Does anyone know how I can investigate the RTS5457V-GR in relation to the control of the CPU? Does anyone have measured values at the PINs of the RTS5457V-GR for comparison? I have read, that the IdeaPad 5 often has problems with the black screen. I will post the results in the article.
Thanks to all.

[pc_okay]

Hello,

I receive two board like this last weeks ~ same symptoms:
https://www.badcaps.net/forum/troubl...tinuously-0-5a

I finally think the blinking of the power button is not important, maybe caused by the battery discharged or absent. (test with the battery, the blinking may stop)

I 'll recheck these board by the end of the week and i'll tell you if i found something.


I think it's not related to the screen, your laptop may not post too, look at your caps lock indicator, i'm sure it's not working when you press it.

PS: all latpop have blackscreen problems, but there are many reasons why! 😉

GL !

[master3112]

I checked the board carefully again. I took measurements on the IT8227E-128 and compared them with data from another user in another forum. The only deviation I noticed was on pins 6 to 10. There I got 0.38V instead of 3.3V. Does anyone know if that could be the cause? I suspect that the CPU is faulty.
2 APUALW_PWRGD 3,29
3 DCIN_ATTACHED_EC 3V
4 N33832385 3.3V
5 SERIRQ 3.29V
6 LPC_FRAME#_R 3.32V 0V38
7 EC_LPC_AD3 3.3V 0V38
8 EC_LPC_AD2 3.3V 0V38
9 EC_LPC_AD1 3.3V 0V38
10 EC_LPC_AD0 3.3V 0V38
11 N2909909242 3,32V
12 VCOREVCC 1.84V
13 CLK_PCI_EC_R 1.65V
14 WRST# 3.26V
15 EC_SMI# 3.32V
18 PM_SLP_S3# 3.32V
20 FP_EC_PWRON 3.29V
21 EC_ON_R_3V 3.29V
22 APU_LPC_RST# 3.31V
23 EC_SCI# 3.29V
25 BATT_CHG_LED# 3.25V
26, 50, 92, 114, 121, 127 +3VL_EC 3,29V
29 BATT LOW LED 3.29V
30 FPR_LED_GREEN# 3.29V
31 GPA5 0.13V 2V4
32 EC_FAN_PWM 1V 0V3
33, 34 3.29V
50 +3VL_EC 3,29V
51-65 KSI/KSO
68 NTC_V1 2.38V 2V5
69 CHG_MOD3R 3V3
70 3V_WLAN_EN_R 3V3
71 ADP_I 0,81V 3V3
72 2_5VEN_R 3.29V
73 PSYS 0,38V
74 +3VL_EC_R 3.29V
76 EC_PD_INT# 3.29V
77 PM_SLP_S5# 3,32V
78 VR_PWRGD 3.31V
79 EC_ON_APU 3V29
80 H_PROCHO+T#_EC 3.32V
81 EC_0.75VALW_EN 3.29V
82 CHG_MOD1_R 3.29V
83 EC_APU_ALWEN_R 3.11V
84 NUM_LED# 3.29V
85 STATUS#_R 5V
86 PBTN_OUT# 3.29V
87 EC_SMB_CK0 0V
88 EC_SMB_DA0 3V31
89 EC_PCIE_WAKE_R# 2V35
90 ENBKL 0V
91 GND
92 +3VL_EC
93 EC_RSMRST#_R 1.88V
94 EC_SMB_CK3 3V3
95 EC_SMB_DA3 3V3
96 EC_SYS_PWRGD 3V3
97 +CAPS_LED# 3.29V 0V
98 BKOFF# 0V
99 NOV_BTN# 3.26V
100 GPG2 3.26V
101 EC_SPI_CS1# 1.80V
105 EC_SPI_CLK 1.49V
106 +1.8VALW 1.82V
107 EC_ON_R_5V 2,97V
108 ACPRN 3.26V
109 LID_SW# 2V29
110 ON/OFF_R 3.26V
111 APU 0V
112 3V32
113 0V
114 +3VL_EC 3V29
115 EC_SMB_CK1 3V29
116 EC_SMB_DA1 3V26
117 EC_SMB_CK2 3V29
118 EC_SMB_DA2 3V29
119 N29099480 2V5
120 USB_CHG_EN 3V29
121 +3VL_EC 3V29
122 SYSON 3V29
123 EC_MUTE# 3V29
124 SUSP# 3V29
125 GPG0
126 P_APU_OCPL_10 2.54V
127 +3VL_EC 3.29V
128 AC_PRESENT 3.29V

THX

[master3112]

Here are voltages for a quick check on inductors if anyone needs it.
PL6202 -5V
PL6201 - 3V3
PL300 - 13V
PL2101- 1V8
PL1901 – 0V77
PL1902 – 1V8
PL1903 – 1V2
PL5601 – 1V1
PL5602 – 1V1
PL5603 – 1V1
PL5604 – 0V77