what makes a laptop screen turn OFF when opened

[Gregory0557]

When the screen is up in normal using position, the screen is off. When the screen is closed about half way, the screen turns on. Continue closing the screen turns off. Moving the screen back to normal using position, the screen is off again. I think it's the Lid Sensor. How dot repair.

[Hawks_Eye · Accepted solution]

Hi @Gregory0557 

Welcome to the HP Support Community! We're here to help you get back up and running.

Thank you for the clear description and for already identifying the lid sensor as a possible cause. That’s a sharp observation, and I appreciate the effort you’ve made to isolate the issue. Let’s walk through how to confirm and address this.

The behavior you're describing—where the screen turns off when fully opened but turns on at a partial angle—is often caused by a misaligned or malfunctioning lid sensor or a damaged display cable that reacts to hinge movement.

What Could Be Causing This

Lid Sensor Misalignment or Fault
Most HP laptops use a magnetic or Hall-effect lid sensor embedded near the hinge. If the magnet or sensor is misaligned, loose, or damaged, it may falsely detect the lid as closed when it’s actually open.

Display Cable Strain or Damage
The display cable runs through the hinge. If it’s pinched, partially disconnected, or worn, it may lose contact when the screen is fully opened, causing the display to go dark.

Power Settings or Sleep Triggers
While less likely in your case, incorrect lid-close actions in Windows power settings can sometimes interfere with display behavior.

 

How to Isolate and Resolve It

Step 1: Test Lid Sensor Behavior

• Slowly open and close the lid while watching the screen and listening for system sounds (e.g., USB disconnect chimes).
• If the screen consistently turns off at the same angle, it suggests a sensor or cable issue—not a software glitch.

 

Step 2: Check for Display Output via External Monitor

• Connect your laptop to an external monitor using HDMI or USB-C.
• If the external display works fine while the internal screen goes dark when opened, the issue is likely hardware-related (sensor or cable).

 

Step 3: Perform a Hard Reset

• Shut down the laptop.
• Disconnect all external devices and power.
• Press and hold the power button for 15 seconds.
• Reconnect power and turn it on.
• This clears residual signals that might affect lid detection.

 

Step 4: Update BIOS and Graphics Drivers

• Visit your laptop’s support page on HP’s official site.
• Download and install the latest BIOS and graphics drivers.
• Example: HP Software and Driver Downloads

 

Step 5: Inspect the Hinge Area (Visually)

• With the laptop powered off, gently inspect the hinge area for signs of:
  • Loose trim or plastic near the hinge
  • Warping or uneven pressure
  • Any visible magnet (small black dot) that may have shifted

If you’re comfortable, gently press around the hinge while opening the lid to see if the screen flickers—this can help confirm a cable or sensor issue.

Let me know your laptop model and whether you’ve noticed any physical damage or recent hinge stiffness. That will help tailor the next steps. You're doing a great job narrowing this down—let’s keep going until it’s fully resolved.

If my response helped, please mark it as an Accepted Solution! ✅ It helps others and spreads support. 💙 Also, tapping "Yes" on "Was this reply helpful?" makes a big difference! Thanks! 😊

Take care, and have an amazing day!

Regards, 

Hawks_Eye

[Gregory0557]

I really do appreciate the response. I think we've pin-pointed it down to the screen sensor.  Is there a video or picture that would help me locate the sensor. Is there a part number or place to order a new one. I've included the product name and serial number. Thanks.

Model = 14a-na0030nr

Serial = #[edited]

[Hawks_Eye]

Thanks for replying @Gregory0557 

You're correct—the lid sensor is likely the issue, and for your HP Chromebook 14a-na0030nr, it's integrated near the hinge area. While HP doesn't sell the sensor as a standalone part, you can reference the service manual and part locator to identify and replace the full top cover or sensor assembly if needed.

Here’s how to proceed:

 

Locate the Lid Sensor

The HP Chromebook 14a-na0030nr uses a Hall-effect sensor, typically embedded in the palm rest or motherboard, and a magnet embedded in the display bezel near the hinge. When the lid closes, the magnet triggers the sensor to signal sleep mode.

To visually identify the components:

• Refer to the Interactive Part Locator for HP Chromebook 14a-na0000 series (PDF).
• The sensor is not labeled separately but is part of the top cover or keyboard deck assembly.

 

Repair or Replace the Sensor

HP does not list the lid sensor as a separate field-replaceable unit. Instead, it is part of one of these assemblies:

• Top cover with keyboard
• Motherboard (if sensor is soldered)
• Display bezel (if magnet is misaligned)

To proceed:

1. Download the HP Chromebook 14a Maintenance and Service Manual.
   • This guide includes disassembly instructions and part numbers.
2. Inspect the hinge area for a small black dot (magnet) or signs of misalignment.
3. If the magnet is intact, the sensor may be faulty—replacement would involve the top cover or motherboard, depending on design.

 

Where to Buy Parts

You can find replacement parts through:

• HP Parts Store

If you’re unsure which part to order, I can help you identify the exact spare part number from the service manual.

Take care, and have an incredible day ahead! 

Regards, 

Hawks_Eye