• Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

It is currently 14 December 2024, 05:43

Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

 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.
 This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).

#1 Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by tknach • 20 May 2024, 11:34
Lenovo Ideapad Flex 5 14ALC05 brak obrazu.
Platforma Wistron LC56-14A
Ryzen 5 5500U
nuvoton ncpe386pb0dx

Płyta startuje.
Brak napięcia PWR_1D2V.
Cewka PL5101 0 Ohm
PU5103 na źrodle, bramce i drenie zwarcie do masy.
Po wylutowaniu tranzystor działa poprawnie.

PU5101
na pinach 5 PWR_VDDQ_VDDQ ,16 PWR_VDDQ_PH,19 PWR_VDDQ_VLDOIN zwarcie do masy

Gdzie szukać możliwego zwarcia ?
Możliwe jest zwarcie na kościach ram ?

Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by Google Adsense [BOT] • 20 May 2024, 11:34

#2 Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by matic • 20 May 2024, 11:57
Hello!

Remove the coil PL5101 from the board and measure the resistances to ground on both pads on the place of this coil.

- If the short circuit to ground is present on the converter side (rail "PWR_VDDQ_PH"), the controller chip PU501 is very likely damaged.
- If the short circuit is present on the system side (power rail "PWR_1D2V"), perform a short circuit test described here (lesson #3). For a short circuit test limit the voltage to 1.2V.

tknach wrote:Możliwe jest zwarcie na kościach ram ?
In the case of a short circuit on the system side, the OnBoard RAM memory chips may be damaged, but there are also other possible causes.

#3 Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by tknach • 20 May 2024, 15:23
Thank you for fast response.
I removed the coil PL5101.
The short circuit is present on the system side (power rail "PWR_1D2V").
From the converter side I have ~1.5 MOhm so no short circuit.
I'm going to perform a short circuit limit voltage test.
I let you know what's happaned.
Thank you so much.

Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by Google Adsense [BOT] • 20 May 2024, 15:23
 This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).
Similar Topics
[BIOS DUMP REQUEST] LENOVO IDEAPAD FLEX 5 14ALC05 LC56-14A 203021-1
[BIOS DUMP] Lenovo IdeaPad Flex 5 14ALC05, MB: Wistron LC56-14A SVT, 203021-1, 448.0MD08.0011
Lenovo ideapad flex 5 14are05 LC55-14A 19893-1M - nie włącza się
LENOVO IDEAPAD GAMING 3 GY535/GY536 NM-D191 - brak zasilania RAM
Lenovo Ideapad Gaming 3 15imh05 brak obrazu
Lenovo Ideapad Legion 5 15IMH05H - brak obrazu

Who is online

Users browsing this forum: ADAMK101 and 5 guests

_______________________________
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.