Laptop black screen: is it the panel, the cable or the board?

A laptop black screen sends most people straight to a quote for a new display. Yet in a fair share of cases the panel is perfectly good, and something cheaper has failed behind it.

Test one: the external monitor

Connect any external monitor or a television over HDMI. Then press the display-switch key combination for your model, usually the function key with a screen symbol.

If the external display works, your processor, memory and graphics are all fine. Therefore the fault sits in the panel, the display cable, or the hinge that carries it.

If the external display also stays dark, the board holds the fault and the screen is innocent. That single test splits the diagnosis in half.

Test two: the torch test

Switch the laptop on, then shine a bright torch at an angle across the screen surface. Look very closely.

If you can faintly make out the desktop or a login box, the panel is producing an image but the backlight has failed. That is often a cheaper repair than a full panel, depending on the model.

Test three: the hinge test

Open and close the lid slowly while the machine is running. Does the image flicker, appear briefly, or change with the angle?

If so, a failing hinge is pinching the display cable. This is extremely common, and it is worth catching early, because a worn hinge eventually cracks the lid frame and the cost multiplies.

Replacing a cable is far cheaper than replacing a panel. Our laptop screen repair page explains how we test the two separately.

What if the screen is cracked?

Then there is no test to run. A cracked panel needs replacing, because nobody can separate and rebond the layers inside. However, we still check the hinge and frame, since the impact that broke the glass often bent something else.

Before you accept a quote

Ask whether they tested the panel and the cable separately. If nobody can answer that, they have not diagnosed the fault, they have guessed at it. Every bench of ours tests both, and you can bring the machine to any of our service centres for a free look.