ACER A315-53G C5V01 LA-E892P rev2A the laptop turns on, but the display does not show

[Ludmilaharhordina]

good afternoon.
need help.
ACER A315-53G C5V01 LA-E892P rev2A
the laptop turns on, but the display does not show.
the laptop came to me from another workshop. visually broken USB 3.0 and soldered BIOS flash drive.
I unsoldered USB 3.0 and flashed several different BIOSes, but it did not help.

+VCC_CORE 0V
+VCC_GT 0V
+VCC_SA 1.03V
+0.6VS_VTT 0.6V
+1.0VALW_PRIM 1.0V
+1.0V.VCCSTU 1.0V
+VCCIO 1.OV
+1.0VS_VCCSTG 1.0V
+1.2V_VDDQ 1.21V
+1.8VALW_PRIM 1.81V
+1.8VS 1.81V
+3VLP 3.27V
+3VALW 3.3V
+3VS 3.3V
+5VALW 5.18V
+5VS 3.3V
+RTCVCC 2.99V
+DDR_DRAMRST# 0.05V +AC_PRESENT 3.27V
+VGA_CORE_EN# constantly changing in range 0.3-0.5V
+VGA_CORE_PG 3.29V
+VGA_EN 3.32V
+VGA_GATE 3.30V
+PLT_RST# 0V
+PLT_RST_BUF# 0V
+PCH_PWROK 0V
+PSIS 0V
+H_CPUPWRGD 0V
+AC_ IN 3.23V
+EC_VCCST_PG 1V
+VR_ON 3.27V
+SIS_PWROK 2.23V

PL907 (+VCC_SA) 1.03V 22 Оm
PL904 (+VCC_CORE) 0V 5.5 Om
PL906 (+VCC_GT) 0V 8.5 Om

PU902 pin:
2 - 1.98V
3 - 4.97V
4 - 5.18V
7 - 0V

UC6 pin 6 - 1V

UC5 pin:
1; 2 - 1V
6; 7 - 1.81V
8; 9 - 1.81V
13; 14 - 1V

UQ1 pin:
3 - 3.27V
5 - 3.27V
1; 2; 4 - 5.18V
6; 7 - 3.3V
8; 9 - 3.3V
10 - 10.73V
12 - 11.18V
13; 14 - 5.18V

schematic and boardview links

https://www.badcaps.net/forum/troubl...-a517-la-e892p
https://www.badcaps.net/forum/troubl...ic?t=123072

[mcplslg123]

+2.5VP present? What about VR_ON?

Since Core voltage is missing , a lot of troubleshooting was un-necessary eg PLTRST# or DRAMRST# will never rise unless Vcore is present.

[Ludmilaharhordina]

+2.5VP 2,5V
VR_ON 3,26V

[Ludmilaharhordina]

+2,5vp 2,5v
vr_on 3,26v

[mcplslg123]

VR_Ready/DRVON?VCC? check these pins on core ic.

[Ludmilaharhordina]

VR_ RDY 3,29V DRVON 4.97V
VCC 5,12V

[Ludmilaharhordina]

here are some more measurements

PU901
pin2 (PWM1_2ph_IA)

[Ludmilaharhordina]

PU901
pin3 (DRVON)

[Ludmilaharhordina]

also checked the working line +VCC_SA (PL907 - 1.03V) for comparison. on PU904 pin2 (PWM_1B_SA)

[mcplslg123]

Try replacing the core voltage IC. Else, no idea on remote basis. this sort of fault is very difficult to sort out without physically having the mb on your table.

[Ludmilaharhordina]

Is it possible that the problem may be in the firmware BIOS?

[Ludmilaharhordina]

What signals should come to PU801 (Ncp81218) to obtain PWM signal PWM1_2ph?
What should be on PSYS? I have nothing on it
thank you for helping me

[Ludmilaharhordina]

I also measured signals on PU801(NCP81218):
SCLK - 1V;
SDIO - 1V;
ALERT# - 0.05V;
SOC_SVID_ALERT# 0.05V (I think it should be 1V). What could be the reason?

[mcplslg123]

Is it possible that the problem may be in the firmware BIOS?

This should've been done at the very beginning.Flash a clean me tested ok bios first.

[Ludmilaharhordina]

I already asked ME BIOS in the topic "Aspire A315-53G need bios dump". Hoaca338 sent me the BIOS file. I flashed this BIOS, but it did not help. And I have no way to flash the EC file.

data about my laptop:
Acer Aspire A315-53G-3786 C5V01 LA-E892P Rev 2A
S/N: NXH18EU0248220D34B3400
SNID: 82205409134

here is a link to the BIOC from Hoaka338:

https://www.badcaps.net/filedata/fetch?id=3605401

here is a link to the bios that was flashed on my laptop :

https://www.badcaps.net/filedata/fetch?id=3605397