• Dell 5420 LA-K491P Znikające napięcie CPU

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 Dell 5420 LA-K491P Znikające napięcie CPU


by ktosik 14 May 2025, 19:04
Witam laptop po uszkodzeniu PU601 UI1 oraz UT3.
Po zanotowaniu nowych układów laptop dał obraz po czym zostawiłem go na noc bez zasilania(odpięta bateria)
Dzisiaj laptop nie daje obrazu zaczyna post po czym zatrzymuje się na 0.6a na początku zasilanie procesora jest obecne po czym znika.
Mogę prosić o jakąś podpowiedź bo usterka daje mi do myślenia.
Dodam że także znalazłem rezystor uszkodzony PR607 zaniżał napięcie na przetwornice PU601 .
Po wymianie tak samo
Oczywiście brak zwarć na cewkach również procesora.

PS. Czy to normalne przy tej konstrukcji że laptop nie uruchomi się jak nie ma wpiętej baterii ?

Re: Dell 5420 LA-K491P Znikające napięcie CPU


by Google Adsense [BOT] 14 May 2025, 19:04

#2 Re: Dell 5420 LA-K491P Znikające napięcie CPU


by matic 15 May 2025, 09:25
Hello!

Measure the voltages to ground on all coils.

#3 Re: Dell 5420 LA-K491P Znikające napięcie CPU


by ktosik 15 May 2025, 11:55
PL101 5,11v
PL601 8,6v
PL701 8,6v
PL201 1,21v
PL100 3,37v
PL501 1.82v
PL301 1,82v
PL603 1,79v
PL602 1,79v

After a while, the consumption drops to 0.3a and the voltage of PL602 and PL603 disappears. The rest of the voltages are present. Also on PU601 pin 31 and 32 3.3v present.

I also changed the bios the board began to boot without batteries.

#4 Re: Dell 5420 LA-K491P Znikające napięcie CPU


by matic 15 May 2025, 17:00
ktosik wrote:I also changed the bios the board began to boot without batteries.
So does the machine works fine now?

Re: Dell 5420 LA-K491P Znikające napięcie CPU


by Google Adsense [BOT] 15 May 2025, 17:00

Who is online

Users browsing this forum: No registered users and 3 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.