Laptop Lenovo IdeaPad 3 15ITL05 doesn’t turn on.

[Evgenii999]

Hello everyone,
I need your advice in diagnosing a motherboard issue on a Lenovo IdeaPad 3 15ITL05, motherboard HS45A/HS55A Rev 1.0 NM-D461 (2020-11-02).
Symptoms:
The laptop does not power on and does not respond to the power button.
Background:
According to the owner, her child was playing on the laptop when it suddenly shut down.
What has been done so far:
Original charger is missing; the non-original one was tested and found faulty (0 V output).
Using a lab power supply (20 V, 0.5 A) — no activity on the board, no LEDs, no standby voltages.
20 V present at the DC jack and PQ100 (MOSFET), but missing at PQ101.
PU100 receives 20 V.
Power consumption 0.030–0.050 A.
The battery (Lenovo L16L2PB3, 7.6 V nominal, 8.7 V charging) was deeply discharged.
Initially 0 V output, BMS locked.
Each cell ~3.2 V, recharged to 4.2 V, but BMS still locked (0 V total).
MOSFET PQ101 (SM3319) was shorted and replaced with the same model.
After replacement, the board shows signs of life:
Orange BATT_CHG_LED turns on when battery is connected.
Battery controller unlocked; charging voltage 8.49 V, battery voltage 8.36 V.
On power button press: fan spins, CPU warms up (no heatsink now), power button and PWR_LED blink.
Current rises to 1.8 A, then drops to 0.3–0.4 A (charging). Without battery – 0.036 A.
Screen stays black, no image on internal or HDMI output.
Voltage measurements:
PJ5901 (V9B+): 8.38 V (battery) / 19.9 V (AC adapter)
PJ5902 (3VALW): 3.35 V in both cases
PJ5601 (V9B+): 8.38 V / 19.9 V
PJ5602 (+5VALW): 5.09 V / 5.11 V
I’ll attach motherboard photos and schematic below.
Question:
Could you please advise which section I should check next, or what could prevent the board from turning on the display?
Thank you!

Schematic - https://www.badcaps.net/forum/troubl...atic-boardview

[khaahk]

How much current is drawn without battery after power button pressed, any voltages on ram, cpu? Slot ram removed - any changes? Resistances on main coils? RTC battery removed - does it autostart?
Can you reprogram bios?

[Evgenii999]

Hi! After I reprogram the BIOS, the Laptop successfully lunched. But now I faced with problem to boot Windows from SSD. The Bitlocker asks the recovery key to unlock the system. I programmed the BIOS with dumb which I downloaded from internet and didn’t change it (didn’t change the motherboard serial number or other data), so I believe that Bitlockers thinks that the motherboard was changed. And the owner of the laptop doesn’t have a Bitlocker key and doesn’t have access to Microsoft account where she can get this key. Is it any way to change motherboard’s serial number in BIOS from Windows/Linux without reprogramming the BIOS again?

[khaahk]

Reprogramming the bios triggers tpm to think that the mainboard has been changed anyways - regardless of the dmi data. In my experience anyways. So you could not have saved the data anyways.

[m1ch43lzm]

+1 to what khaahk said, the firmware TPM is emulated by the Intel ME, flashing a new BIOS with clean ME will reset TPM, which stores the decryption key
Copying the DMI will only restore unique system data such as S/N, model, machine type, UUID; and the Win license key is also stored in the BIOS

Check this video:
https://www.youtube.com/watch?v=5rPOxb8KJ9U

Windows 11 forces Bitlocker/Device Encryption when you setup a MS account on a clean install/new laptop, and the worst part is that you don't even know about it until it's too late, nowhere during OOBE you get to take note of the 48 digits recovery key should you need it, instead it's stored on the MS account automatically and the customer has to remember MS account credentials
Even if you bypass MS account the drive still has BitLocker albeit in a "suspended" state, you have to disable Device Encryption from Settings
When in "Suspended" state the key is stored somewhere on the drive, but the data is still encrypted (regular BIOS updates from Windows usually suspend Bitlocker for 1 reboot count, as updating BIOS via the regular procedure also resets the TPM, then after a successful boot the key is stored again in the TPM)
Maybe the laptop was setup by another person, then the bitlocker key is in that person's account, if you can't get the key, goodbye data as you have to format and reinstall Windows

https://support.microsoft.com/en-us/...3-056f5ab347d6

That's why I disable BitLocker/Device Encryption for home customers, or at least take note of the recovery key when the laptop still works

To backup the key (before it's too late), open command prompt as admin then run the following:

manage-bde -protectors -get  C:

[Evgenii999]

@ khaahk @m1ch43lzm Thank you very much for the response!!

[reformatt]

With Windows 10/11 installers created with Rufus, you have the option to disable Bitlocker encryption by default. On factory installs, only machines that support 'Modern Standby' power states have Bitlocker automatically enabled.

I also noted on a laptop recently that Bitlocker was in suspended mode as the user had not fully completed his sign in correctly for his MS account. So this maybe a change MS has done to prevent full encryption until the key is at least backed up to an account. Then we get the issue of multiple accounts on the one machine and we don't which one the key is backed up on.......

I always check each laptop for BDE before I work on it and backup the key if so. Saves those deer in the headlight stares from customers about what the hell I'm talking about and their denials they ever setup such a thing. You can literally waste an hour on this bullshit with them not knowing their password, or they don't have access to their 2FA device. At least Apple have a way to reset FileVault by iCloud etc, there is no fall back option with MS.

[m1ch43lzm]

With Windows 10/11 installers created with Rufus, you have the option to disable Bitlocker encryption by default. On factory installs, only machines that support 'Modern Standby' power states have Bitlocker automatically enabled.

As in, most laptops made after 2019-2020 that can be upgraded to Win11; you can also bypass the Bitlocker/automatic Device Encryption during OOBE on the factory install if you can open a command prompt with Shift-F3 (or Shift-Fn-F3)

reg add HKLM\SYSTEM\CurrentControlSet\Control\BitLocker /v PreventDeviceEncryption /d 1 /t REG_DWORD /f

Or manually open regedit from command prompt during OOBE and set the same key
Win11 24H2 onwards they dropped the requirement for "Modern Standby", you can get Bitlocker on desktop PCs too...
https://learn.microsoft.com/en-us/wi.../oem-bitlocker

I also noted on a laptop recently that Bitlocker was in suspended mode as the user had not fully completed his sign in correctly for his MS account. So this maybe a change MS has done to prevent full encryption until the key is at least backed up to an account. Then we get the issue of multiple accounts on the one machine and we don't which one the key is backed up on.......

Or bypassed the MS account, either by themselves or by the shop they bought the laptop from, I even got this suspended Bitlocker on a clean Windows 10 install with local account on my own laptop
On that case, I disable Device Encryption from Settings, and wait until the drive is fully decrypted, then change the "not fully logged in" MS account to Local account; for now MS isn't forcing to switch to MS account if you already have a local account
But if during OOBE you setup a real MS account with the intent to change to a Local account later, the key is on that MS account; in that case if you don't know that account credentials you're out of luck..

I always check each laptop for BDE before I work on it and backup the key if so. Saves those deer in the headlight stares from customers about what the hell I'm talking about and their denials they ever setup such a thing. You can literally waste an hour on this bullshit with them not knowing their password, or they don't have access to their 2FA device. At least Apple have a way to reset FileVault by iCloud etc, there is no fall back option with MS.

+1 to that, if laptop still powers on and comes for a regular maintenance (cleaning, replacing thermal paste, etc.); bad design decision by MS to not tell users during OOBE "here's your bitlocker key, take note of it or save it to a USB drive, you will need it later if your device breaks", regular users don't even know Bitlocker/automatic Device Encryption is done, some don't even know what's a MS account as the laptop was setup by someone else, they barely know the User account PIN
Unless the laptop doesn't boot by a corrupted BIOS (you may be lucky if a regular BIOS update failed and Bitlocker was "suspended" for 1 reboot count before the BIOS update), or worse, you have to replace motherboard if the CPU is dead/motherboard can't be repaired for example
The "fall back" is supposed to be the MS account...