Jan 04, 2020
iPhone display issues like screen flickering, white boxes, grey lines, red screen and blue screen are quite annoying. Luckily, you have found us. REWA chip-level motherboard repair service is aimed to help repair shops solve motherboard issues they could not handle by themselves. Today we will share a special repair case REWA LAB has helped with - iPhone XS Max abnormal screen display troubleshooting. Most importantly you need to understand the root causes of the screen flickering before undertaking any of remedies.
Here we have an iPhone XS Max motherboard from a client that comes with abnormal screen display.
Connect an iPhone XS Max display assembly with the motherboard, and connect the battery connector with the DC Power Supply. Get the motherboard powered on with tweezers. We can see that the screen comes with abnormal display and the boot current is larger than normal value. However, the phone can access the activation screen. Judging by this, the display problem is probably related to the display circuit, the GPU circuit or the third space PCB.
Let’s check the display circuit first. Run diode mode measurement of the display connector J5700. The measured value is normal. So the display problem has nothing to do with the display circuit.
Next, we need to check the GPU circuit. We need to separate the motherboard before the test. Place the motherboard on the specialized Heating Platform. 3 minutes later, pick up the upper layer with tweezers and then the lower layer.
The problem remains the same. Which indicates that the display problem has nothing to do with the third space PCB.
We need to continue with the GPU circuit. Attach the upper layer to the PCB Holder. Open REFOX and find the GPU circuit of iPhone XS Max. Compare the upper layer we are dealing with and the one on the bitmap. We find that the one we are dealing with is an iPhone XS upper layer, not an iPhone XS Max upper layer as described.
Upper Layer Comparison
Try to connect an iPhone XS display assembly with the upper layer and connect the battery connector with the DC Power Supply. Get the upper layer powered on with tweezers. The phone turns on normally with a normal display. The phone can access the activation screen and the boot current is also normal this time.
We can confirm now that our client soldered an iPhone XS upper layer onto an iPhone XS Max lower layer, and resulted in the abnormal screen display.
REWA repair masters suggest that repair technicians keep a well-organized workspace in their daily repair work. You can develop a good habit by dividing your workspace into different areas according to different needs. For example, the repair area, the refurbishing area, tools/consumables, etc..
Tools and Parts Used In The Video:
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REWA is a world leading electronics repair business solutions provider who was founded in 2008 in HongKong. We are committed to delivering one-stop services covering Sourcing Solution, Technical Support Solution as well as Recycle & Resell Solution.