By David Coe, founder and bench technician
Black screen but the laptop is on: check the backlight first
A laptop that lights up, sounds alive and shows nothing is one of the most misdiagnosed jobs on any shop's bench. The screen gets blamed and sold, the customer comes back, and only then does everyone suspect the board. Here is how to tell the difference before anyone orders a panel.
The two tests that settle it
- Shine a torch at the panel. If you can faintly see the login screen or desktop in the glow, the screen is drawing an image and the backlight is missing. That is a board-side fault, not a dead panel.
- Connect an external display. If the laptop drives an external monitor happily, the GPU and board are alive enough to start; the fault is in the internal display path, and the torch test above tells you which half.
What actually fails
- The backlight fuse: a tiny component that dies to protect the rest of the circuit. Often the whole fault.
- The boost/driver circuit: the chip (and its inductor) that steps voltage up to feed the LED strip.
- The display connector on the board: cracked solder or corroded pins after liquid or a strain on the cable.
- The panel's own LED strip: the genuine screen failure. Rarer than its reputation, which is the point of this page.
Why it matters to your quote
A panel is the most expensive part you can sell on this job; if the fault is a backlight fuse, you have sold the customer the wrong repair and created a comeback. Ten minutes with a torch and an HDMI cable protects both the margin and the reputation, and if the board is the fault, it is a fixed £120 + VAT job including return post in both directions, not a £400 screen.
What we need sent in
The complete laptop, not just the board. We test the backlight against a real panel and cable before it goes back. Diagnosis is £35 + VAT, waived when the repair goes ahead; the priority slot at £180 + VAT exists for the jobs a customer cannot wait on. If the panel itself is the fault, that finding comes back on the ticket too, so your screen sale is at least the right one.
Backlight and no-image questions
How can I tell if it's the screen or the board?
Torch test plus external display. A faint image under torchlight means the backlight circuit. Board side. External display fine but the panel dark points at the display path, usually the board. A panel that fails every test is the genuine screen failure, and the ticket says so.
Do you supply screens?
No. The bench does logic boards, not panels. What you get is a definitive finding: if the panel needs replacing, the ticket says so, so your screen sale is the right one.
What does the repair cost?
£120 + VAT if the board is the fault (post both ways included) or £180 + VAT in the priority slot. Diagnosis is £35 + VAT and is waived when the repair goes ahead.
Do I send the laptop or just the board?
The complete laptop. Backlight faults are tested against a real panel and cable before return.
The books are full. Join the list
Our bench is at capacity, so we are not taking new jobs right this moment. Open a trade account and we will email you the moment we are booking again. No commitment. Questions? Email jobs@soldersector.com.
