Problem with brightness when I open my laptop (plugged or unplugged)

[angie001_]

I am writing to request assistance with a persistent display brightness issue on my OMEN-17t an-100 CTO with a GXT 1070 The screen has been consistently dim on startup, and this problem has been present both when the laptop is running on battery and when it is plugged into the AC adapter.

​The issue began after I received a "CMOS is invalid" error, which was subsequently resolved by the system's automatic BIOS reset. Shortly after, I also replaced the laptop's main battery. While the laptop now functions, the screen brightness problem remains. I have since confirmed that the brightness issue was also present before the new battery was installed.

​Here is some key system information:

• ​Product Name: OMEN by HP Laptop
• ​BIOS Version: F.19
• ​System Board ID: 845A

​I have performed a number of troubleshooting steps to diagnose and resolve this issue, but the problem persists. Here is a detailed list of the steps taken:

• ​Driver and Software Troubleshooting:
  • ​I performed a clean installation of the NVIDIA graphics driver, reverting to an older, known-stable version to rule out a driver bug.
  • ​I checked and adjusted the power management settings within the NVIDIA Control Panel.
  • ​I confirmed that there are no HP-specific power management applications installed on the system, such as HP Power Manager or OMEN Gaming Hub.
  • ​I have verified that all Windows power settings are set for optimal performance and that "adaptive brightness" is not an available option.
• ​BIOS and Hardware Diagnostics:
  • ​The BIOS was reset to its factory default settings following the initial "CMOS invalid" error.
  • ​I confirmed that the brightness issue persists even when viewing the BIOS Setup Utility menu, ruling out a Windows-level software problem.
  • ​I ran the HP PC Hardware Diagnostics UEFI tool. Both the AC Adapter Test and the Battery Test passed without any errors.

​The most critical finding from my troubleshooting is that the screen's brightness is low even when the system is operating within the BIOS and diagnostic menus. This indicates that the problem is not related to the Windows operating system or its drivers.

​Based on these results, I believe the issue is either a hard-coded power management setting within the BIOS that cannot be changed through the standard menus or a physical hardware fault with the display itself.

​Could you please provide guidance on the next steps I should take? I would like to know if there is a known fix for this issue or if a professional repair is necessary.

​Thank you for your time and assistance.

[Samrit26]

Hello,

Thanks for the detailed write-up — this is exactly the level of troubleshooting I’d expect before escalating, and your conclusion is directionally correct.

I’ll walk through this the same way I would mentor internally, separating what we’ve proven, what remains possible, and what HP’s supported next steps are.

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What you’ve already proven (this is key)

You’ve done the right isolation steps, and a few findings are decisive:

1. Dim brightness present in BIOS and HP UEFI diagnostics

   • This fully eliminates Windows, NVIDIA drivers, Intel iGPU drivers, power plans, and OMEN software

   • Anything visible in BIOS is controlled by firmware + embedded controller (EC) + panel hardware

2. Issue existed before and after battery replacement

   • Rules out the replacement battery itself

   • Also rules out Windows power calibration issues

3. CMOS invalid → automatic BIOS reset

   • This is the first red flag

   • On OMEN systems, a CMOS event can sometimes expose latent EC or panel issues

At this point, your troubleshooting has already gone beyond what frontline support usually asks for.

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Remaining technical possibilities (ranked by likelihood)

1. Panel backlight degradation or failure (MOST LIKELY)

On the OMEN 17t-an series (especially GTX 1070 configs), the LCD assembly uses:

• LED backlight driven by panel-side circuitry

• Brightness control signal comes from EC, but actual luminance depends on panel health

Symptoms that match perfectly:

• Dim but visible image

• Brightness keys may respond logically, but luminance doesn’t change meaningfully

• Dim even in BIOS

• Stable, not flickering

👉 This usually means:

• Backlight LEDs are aging/failing or

• Backlight power circuitry on the panel is degraded

This is not repairable at component level in the field — HP replaces the LCD assembly.

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2. Embedded Controller (EC) stuck in a low-brightness state

Less common, but technically possible after a CMOS event.

However:

• You already did a BIOS reset

• BIOS F.19 is relatively late for this platform

• There is no user-accessible EC reset beyond full power drain

This leads to one remaining firmware step (see below), but historically this model does not recover from EC brightness faults reliably.

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3. BIOS corruption affecting panel power tables

Unlikely, but worth addressing once before declaring hardware failure.

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One final firmware step I would attempt (low effort, low risk)

Even though you’re already on F.19, I would still do a forced BIOS reflash:

1. Download BIOS F.19 again from HP Support (do not rely on existing image)

2. Flash it from within BIOS (F10 → Update BIOS) if available
   or from a USB recovery method

3. After flash:

   • Power off

   • Disconnect AC

   • Remove bottom cover

   • Disconnect main battery

   • Hold power button 15–20 seconds

   • Reconnect battery, AC, power on

Why this matters:
This is the only way to force the EC to fully reinitialize panel power rails after a CMOS event.

If brightness is still dim in BIOS after this → firmware is conclusively ruled out.

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What HP support will conclude (and I agree with)

Based on your evidence, HP’s official stance will be:

The issue is isolated to hardware, specifically the display assembly, and cannot be resolved via software or BIOS configuration.

For OMEN laptops:

• Display backlight is not a field-replaceable sub-component

• The supported fix is LCD assembly replacement

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Repair path (important to be clear)

For HP notebooks:

• Only option is depot repair (ship-to-repair center)

• No onsite or customer self-repair for display assemblies under HP support

• If out of warranty, it becomes a paid LCD replacement

If the unit is out of warranty and you’re considering third-party repair:

• Entire LCD assembly must be replaced (panel + backlight)

• Part number depends on:

  • Panel size (17.3")

  • Resolution (FHD vs QHD)

  • Refresh rate