Vertical lines on monitor 27ER)

[Julien2044]

Hi,

I am having the same issue with a Hp 27ER connected to an iMac.

[VikramTheGreat]

Hi @Julien2044,

Welcome to the HP Support Community.
 

Thank you for posting your query. I will be glad to help you.

Seeing vertical lines on your 27ER monitor when connected to an iMac can be frustrating and concerning. Here's how to diagnose and address the problem, using clear, step-by-step guidance:

Step 1: Rule Out Connection & Cable Issues

1. Power-cycle the monitor: turn it off, unplug it for a minute, then plug it back in.
2. Inspect and reseat the cable connecting the monitor and iMac (HDMI, DisplayPort, etc.): unplug it and plug it back firmly.
3. Try a different cable or port, if available. 

👉 If the lines disappear after changing cable/port, the original cable or port may be faulty.
 

Step 2: Test with Another Device

• Connect a different device (e.g., a laptop) to the monitor.
• If the vertical lines persist, the issue lies with the monitor.
   

Step 3: Check Graphics Output from iMac

• Use Spotlight to search for “Safe Boot”, restart into safe mode, and see if the lines persist.
• Alternatively, connect an external display to the iMac: 
  • If the external display is clean, the iMac’s GPU or logic board may be fine, and the issue is the monitor.
  • If lines appear on both, the source may be the iMac’s output.
     

Step 4: Inspect Monitor Internals (if applicable)

If you're confident opening electronics:

• Inside the monitor, a loose or damaged ribbon cable between the board and LCD panel might cause lines.
• This, however, requires technical skill, and may not be recommended for everyone.
   

Step 5: If the Fault Is Within the Monitor

If cables, ports, and external tests point to the monitor:

• The LCD panel itself may be damaged, as confirmed by the HP community.
• In many 27ER cases, the panel is the culprit and typically requires replacement, often not repairable

I hope this helps.

Take care and have an amazing day!
 

Did we resolve the issue? If yes, please consider marking this post as "Accepted Solution" and click "Yes" to give us a helpful vote - your feedback keeps us going!

Regards,

VikramTheGreat