HP 24" LP2475W screen lights up with a vertical bar about 3 inches wide, no menu

[morganboy]

HP 24" LP2475W lights up with a vertical bar about three inches wide,  scrolling lines  no menu, could this be in the main board or a power supply issue? Something to do with horizontal hold? Worked great for years died. Seen reference to a failure of a diode in the power supply for a blank screen, but mine comes on. Seen parts, main board, and power supply for sale. I'm a retired engineer, never worked on a monitor or TV, just radios and digital devices.

[MysteriousMe]

Welcome to HP Support Community, @morganboy 

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

Step 1: Check OSD (Menu)

Turn off the monitor.

Disconnect all video cables.

Turn the monitor back on.

Result:

If the OSD still does not appear → problem is in the panel/T-Con or LVDS path.

Step 2: Reset Power

Unplug the monitor from AC.

Hold the power button for 10 seconds.

Plug it back in and test.

Step 3: Flashlight Test

With the monitor on, shine a flashlight at the screen.

Look for faint shapes or menus.

Interpretation:

Nothing visible → panel is not drawing an image.

Step 4: Check Cables Internally

(Only if you are comfortable opening the monitor.)

Remove the back cover.

Locate the LVDS cable (from main board to panel).

Unplug and re-plug both ends.

Inspect the cable for damage or looseness.

Step 5: Check T-Con Board

Look at the T-Con (attached to or behind the LCD panel).

Inspect for burnt spots or cracked components.

Test the small fuses (usually F1/F2) with a meter for continuity.

Step 6: Test with Another Input

Connect HDMI.

Connect DVI.

Connect DisplayPort.

If the issue is identical on all inputs → panel/T-Con problem.

Step 7: Thermal Test

Turn on the monitor.

Gently press around the screen edges where ribbon-cable bonds are located.

If the picture changes or flickers → panel tab-bond failure.

Step 8: Rule Out Mainboard

If the monitor powers on consistently

Backlight works normally

Buttons respond (LED changes)

Then the mainboard is less likely the cause.

I hope this helps.

Take care and have a good day.