• Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu

Forum rules:Click here to view the forum rules

  1. Topic title should contain: the device's manufacturer, full model and the brief description of problem.
  2. Topic message should contain: the PCB marking code (required in case of hardware repairs), an extended description of problem, things you have checked/replaced/measured, your conclusions and the question. If you are not able to find the PCB marking code, please read THIS TOPIC. If you still cannot locate the PCB markings, please upload a clean, both-side photos of the mainboard - it is required to remove any films, modules or brackets possibly covering these markings.
  3. Before posting a new topic please read all topics in TRAININGS subforum and make a preliminary diagnostic based on the content of those trainings.
  4. Uploading of any complete schematics, BIOS / firmware files or any other kind of documentation, or linking to 3rd party websites with such files, is STRICTLY PROHIBITED. You can only upload the small portion of documentation or, link to BIOS file on UNVERIFIED BIOS FILES subforum, which simplifies the diagnostics/repair. You are not allowed to upload more then one complete page of instruction/schematic per single topic. The file you upload must not contain any watermarks, "confidential" markings, links or email addresses and cannot be password-protected.
  5. It is only permitted to describe one faulty device per single topic - you should always open a new topic for each subsequent device.
  6. Requesting of the full schematics, BoardView files, BIOS files or any other kind of documentation is NOT ALLOWED in this subforum. If you need to ask for any of these, you should open a new topic in DOCUMENTATION/BIOS REQUEST subforum.

#1 Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 30 March 2024, 11:24
Witam,

Lenovo Legion 5 15IMH05H NM-C911 Rev: 1.0

Laptop trafił do mnie na brak obrazu po HDMI, jednak okazuje się, że już od dawna nie miał również obrazu na matrycy.
Jakiś serwis stwierdził że nie ma części do niego aby to naprawić i właściciel korzystał z laptopa po HDMI (i teoretycznie zależy mu jedynie aby tą funkcjonalność naprawić).

Laptop uruchamia się normalnie, wchodzi do systemu - słychać melodie powitalną Win11. Brak obrazu na matrycy, HDMI oraz po USB-C.
Bios podmieniany na inny, bez zmian - Win11 uruchomił się. HDMI oraz taśma matrycy przedzwoniona.
Brak napięcia na PL3102, rezystancja około 2-3 ohm.
Brak napięcia na pin 4 z UG9.
Reszta przetwornic wygląda, że pracuje prawidłowo.

Proszę o pomoc w diagnozie - wracam do tematu naprawy elektroniki po kilku latach przerwy przez budowę domu :)

Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by Google Adsense [BOT] 30 March 2024, 11:24

#3 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 30 March 2024, 15:40
UR3 not exist on my motherboard.

Image

#4 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 30 March 2024, 22:01
Perform the following measurements while the machine is booted into the OS:
- Measure the voltages to ground on pins 15, 16, 18 of HDMI connector with the external HDMI screen connected.
- Measure the voltage to ground on pin 19 of HDMI connector with and without external HDMI screen connected.

#5 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 1 April 2024, 21:07
Pin 15: 4,24 -> 4,96V after OS booted
Pin 16: 4,35 -> 4,96V after OS booted
Pin 18: stable 5,09V
Pin 19: 0,2V without external HDMI screen

#6 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 2 April 2024, 08:37
matic wrote:Measure the voltage to ground on pin 19 of HDMI connector with and without external HDMI screen connected.


#7 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 2 April 2024, 08:46
Oh, sorry for that - voltage is something around 5V with external HDMI screen connected.

#8 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 2 April 2024, 09:38
Measure the following voltages to ground with and without external HDMI screen connected:
- On pin 1 of transistor QG4.
- On pin 3 of transistor QG6.

Transistors QG4, QG6 pinout:
Image

#9 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 2 April 2024, 17:39
With and without HDMI screen connected values are the same
- Pin 1 of QG4 = 1,8 V
- Pin 3 of QG6 = 0,2 V

Sometimes (random reconnect) with HDMI connected is 2,8V on QG6 pin 3 then on QG4 pin 1 is 64mV.

#10 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 3 April 2024, 10:08
Measure the following voltages to ground with and without external HDMI screen connected:
- On all pins of transistor QG6.
- On both pins of resistor RG58.

#11 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 3 April 2024, 21:28
QG6 with and without HDMI: 1 - 0,2V; 2 - 3,3V; 3 - 0,2V
RG58 with and without HDMI: 0,2V and 105mV

One time (random reconnect) on RG58 was 4,96V and 0,5V probably.

#12 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 4 April 2024, 09:33
Use a continuity tester and check the following connections:
- Between pin 19 of HDMI connector and pin 2 of resistor RG58.
- Between pin 19 of HDMI connector and pin 1 of transistor QG6.

#13 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 4 April 2024, 21:02
Those connections have 0 Ohm, but I found small problem with losing connection on HDMI port with pin 19. After resoldering now everytime with HDMI connected is 2,8V on QG6 pin 3 and on QG4 pin 1 is 64mV. RG58 have 4,96V and 0,57V.
Checked again connections between HDMI pins on MB and 2nd end of HDMI cable. Looks good.

Still no video on HDMI.

#14 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 9 April 2024, 10:38
Please, remeasure the following voltages to ground with and without external HDMI screen connected:
- On pins 1, 2 of transistor QG4.
- On pins 1, 3 of transistor QG6.

#15 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 9 April 2024, 19:11
Thank you for answer!

With HDMI:
QG4 pin 1: 65mV, pin 2: 0,58V
QG6 pin 1: 4,98V, pin 3: 2,81V

Without HDMI:
QG4 pin 1: 1,81V, pin 2: 106mV
QG6 pin 1: 0,21V, pin 3: 0,21V

#16 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 10 April 2024, 07:34
Set your multimter to the diode test mode and measure te following voltage drops to ground:
- On pin 1 of capacitors CG32, CG33, CG34, CG35, CG36, CG37, CG38, CG39.
- On pins 1, 4 of transistor QG3.

#17 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 10 April 2024, 21:29
CG32, CG33, CG34, CG35, CG36, CG37, CG38, CG39 pin 1: 0,314V on all capacitors

QG3 pin 1 and 4: 0,622V on both

#18 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by matic 11 April 2024, 07:05
Measure the voltages to ground on all coils.

#19 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 11 April 2024, 07:14
All looks good, in first post was information about missing voltage on PL3102:
DemoNx4 wrote:Brak napięcia na PL3102, rezystancja około 2-3 ohm.
Brak napięcia na pin 4 z UG9.
Reszta przetwornic wygląda, że pracuje prawidłowo.

But if you want, I can check it again and post here later all values.

#20 Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by DemoNx4 16 April 2024, 21:50
Sorry for the long reply time - my son was born :)

PL1401: 0,964V
PL3201: 0,996V
PL3001: 0,967V
PL3002: 0,966V
PL3003: 0,966V
PL3004: 0,966V
PL3102: 0V
PL8201: 1,202V
PL8202: 1,204V
PL7501: 0,751V
PL7502: 0,756V
PL7503: 0,759V
PL2701: 1,228V
PL2001: 3,31V
PL2002: 5,12V
PL1301: 1,067V
PL101: 0,219V

Re: Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu


by Google Adsense [BOT] 16 April 2024, 21:50

Who is online

Users browsing this forum: Google [Bot] and 1 guest

_______________________________
All rights reserved. Unauthorised copying of this website's content or any of its part is strictly forbidden.
Any trademarks, brand names, products or services published on this website belong to their legal owners, are copyrighted and used for information purposes only.