A Samsung Galaxy Tab A 10 (SM-T515) came to our repair bench with a display backlight not working problem.
At first, the display itself was suspected to be the cause. A replacement display was tested, but the backlight problem remained exactly the same.
This indicated that the fault was not simply a defective display. The motherboard and its backlight circuit needed to be checked.
Using Borneo schematics, the backlight circuit was traced and each relevant line was checked. During the inspection, a burned and open coil was found on the LED 27P line.
The faulty coil was removed, and the connection was restored with a jumper. After the repair, the display backlight came back and the tablet was successfully repaired.
Device Information
| Details | Information |
|---|---|
| Brand | Samsung |
| Device | Galaxy Tab A 10 |
| Model | SM-T515 |
| Problem | Display backlight not working |
| Initial attempt | Display replacement |
| Schematic | Borneo |
| Fault found | Burned/open coil |
| Repair | Jumper connection |
| Result | Backlight restored |
🔧 Customer Complaint
The Samsung Galaxy Tab A 10 T515 was received with a no-backlight display problem.
The display was not illuminating correctly, so the first step was to determine whether the display assembly itself was faulty.
🖥️ Display Replacement Did Not Solve the Problem
A replacement display was installed and tested.
However, even with the replacement display:
The backlight was still not working.
This was an important clue.
If a known-good replacement display produces the same fault, continuing to replace displays is unlikely to solve the problem. The next step is to inspect the motherboard and the backlight circuit.
🔍 Moving to Motherboard-Level Diagnosis
The tablet was disassembled carefully so that the motherboard could be inspected.
The backlight circuit was checked using Borneo schematics.
The relevant lines and components were checked to determine where the backlight circuit was being interrupted.
During this inspection, one coil was found to be burned and electrically open.
The damaged component was located in the LED 27P line of the backlight circuit.
This explained why changing the display had not solved the problem.
🔥 Finding the Burned and Open Coil
The damaged coil was visibly burned and was no longer providing continuity through the circuit.
An open component in an important backlight path can prevent the display backlight from operating even when the display panel itself is perfectly good.
This was the key finding in this repair:
Display → Good replacement tested → Backlight still dead → Motherboard circuit checked → Open coil found
🛠️ Repair Procedure
After confirming the faulty component and checking the circuit with the schematic, the damaged coil was removed.
The affected connection was then restored using a jumper.
The jumper restored the required electrical connection across the open section of the circuit.
Important: A coil should not automatically be bypassed with a jumper. Its function and position in the circuit must first be confirmed using the schematic and appropriate measurements. The jumper method described here relates specifically to this repair.
💡 Backlight Restored
After completing the repair, the tablet was powered on and tested.
The result was successful:
- ✅ Display working
- ✅ Backlight restored
- ✅ No need for another display replacement
- ✅ Motherboard fault repaired
- ✅ Samsung Galaxy Tab A 10 T515 returned to working condition
Problem solved.
📐 Why Schematic-Based Troubleshooting Matters
This repair demonstrates why motherboard-level diagnosis is important in tablet and mobile phone repairing.
A common approach to a backlight problem is:
Backlight not working → Replace display
But this isn’t always the correct solution.
When a replacement display does not change the symptom, the technician should investigate the motherboard.
Using a schematic makes it possible to:
- Identify the backlight circuit.
- Trace the relevant lines.
- Locate coils and other components.
- Check continuity.
- Find an open circuit.
- Identify the actual defective component.
- Perform the appropriate repair.
In this case, schematic-based troubleshooting helped locate the open coil on the LED 27P line.
👨🔧 Technician Tip
Don’t assume every backlight problem is a display problem.
If you have already tested a known-good display and the backlight remains dead, start checking the motherboard.
A good troubleshooting sequence is:
Display → Display connector → Backlight lines → Coils/components → Backlight power circuit
Checking the circuit systematically can save both time and replacement-display cost.
🧰 Tools and Equipment
The following equipment can be useful for this type of motherboard repair:
- Digital multimeter
- Microscope
- Soldering station
- Hot air rework station
- Jumper wire
- Borneo schematic/boardview
- DC power supply, when required
For board-level repairs, accurate measurement and schematic tracing are often more important than simply replacing parts.
⚠️ Important Repair Note
Before replacing or bypassing any motherboard component, always verify its function using the appropriate schematic and measurements.
A jumper is not a universal replacement for a coil. Depending on the circuit, a coil may perform filtering or other electrical functions, so bypassing it without understanding the circuit can cause additional problems.
In this particular T515 repair, restoring the affected connection successfully brought the backlight back.
✅ Final Result
The Samsung Galaxy Tab A 10 SM-T515 arrived with a non-working display backlight.
A replacement display was tested first, but it did not solve the problem.
The motherboard was then examined using Borneo schematics, and a burned/open coil on the LED 27P line was identified.
After removing the damaged coil and restoring the connection with a jumper, the display backlight came back successfully.
Repair Status: ✅ Successfully Repaired
Frequently Asked Questions
Why was the Samsung T515 backlight not working?
In this repair, the problem was caused by a burned and open coil in the backlight circuit, rather than the display itself.
Did replacing the display fix the problem?
No. A replacement display was tested, but the backlight remained non-functional.
How was the fault found?
The motherboard backlight circuit was traced and checked using Borneo schematics, which helped locate the open component.
What was repaired?
The damaged/open coil was removed and the affected connection was restored with a jumper after verifying the circuit.
Can every T515 backlight fault be repaired this way?
No. Different devices can have different backlight faults. The actual circuit should always be checked before deciding on a repair method.
FlashSoftFix Repair Case:
Samsung Galaxy Tab A 10 (SM-T515) — Backlight Not Working → Motherboard Diagnosis → Open Coil Found → Jumper Repair → Backlight Restored.
