Chosen Solution

the other day i was changing thermal past on cpu and and i forgot to unplug battery and she i was disconnecting lvds cable i probably short the power of lcd something like that – the screen was white than you turn machine and you could see vertical lines if you look from top angle , so i took it to the shop and the guy fixed this problem , display work now but there is a wavy lines on the bottom of display like if not all leds working , i asked the guy about this and he told me that the problem in display module , so i bought a new display module , but on the new module is absolutely the same thing , not sure where to go from this ,on schematic i see this LP8550 controller i guess. if this would be broken ,i mean could it be part broken like not fully ,maybe you guys have experience in this and could help me one the pic i show what the guy did to make display work again and what i don’t like to see is that just Thin wire,, is this even okay ? or this thing that died there had zero resistance anyway ?

and thats how those waves looks like

Looks like your original issue was with L9004 burning out, which causes a white screen. Can’t see clearly from the picture, but usually you do have to solder a new ferrite bead and add a wire too, when it burns it nearly always destroys 1 or both solder pads for the component. Regarding this issue, I would firstly check both sides of the LCD cable (make sure no melted plastic, pins aren’t chipped/bent and the gold dots on the bottom of the pins are not dull looking) and also clean this using isopropyl. I would then use a soft brush and isopropyl to clean inside the LCD connector. This issue is nearly always caused by debris or dried solder flux inside the connector/on the cable, I have had the same issue when soldering around the connector before, flux has always caused interference with this. This will especially be the case if these backlight marks where not visible when you had the initial white screen issue. If it is not this, it will likely be the LED return resistors, but it is very rare for these to have issues unless they were liquid damaged, knocked or soldered before. Give the connector and cable a good clean first, which should sort your issue.

Tell him to look the connections between LVDS 24 to 29 pins and the R9717, R9718, R9719, R9720, R9721 and R9722 and their values. It happens very often

Don’t worry if in my image you see the 820 2936 motherboard and yours is 820 3115, is the same thing but I don’t find mi 3115 files