Try connecting an external monitor to the laptop and check its' display.
If it is OK then as you've changed the LVDS cable the only things left are the display panel or perhaps the connectors on the motherboard or display but more likely the display panel
If the external monitor is the same then it is the GPU or the motherboard.
What is the full model number of the laptop?
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=== Update (11/26/2018) ===
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Hi,
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it seems as though the display panel is faulty and needs to be replaced.
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Here’s a link to the [http://h10032.www1.hp.com/ctg/Manual/c04510889|service manual] for your laptop, taken from this [https://support.hp.com/us-en/product/hp-envy-15-k200-notebook-pc-series/7527530/model/7633471/manuals|webpage].
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Scroll to p.48 to view the necessary pre-requisite steps and then the procedure to remove the display panel.
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Also on p.47 & 48 you’ll find the part numbers for the various display panels available for the model series.
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Find the part number appropriate to your particular model (usually it is stamped on the back of the display panel if you wish to verify the part number) and once you have the correct part number, search online, using the part number ''only'' in the search box of your browser to get suppliers of the part.
Hi ,
Try connecting an external monitor to the laptop and check its' display.
If it is OK then as you've changed the LVDS cable the only things left are the display panel or perhaps the connectors on the motherboard or display but more likely the display panel
If the external monitor is the same then it is the GPU or the motherboard.
What is the full model number of the laptop?