Predator PH317-55 display problems: HDMI port stopped working and now Internal display has stopped

If you get an external image from the "Mini DisplayPort, HDMI port and the DisplayPort and it works fine with external monitor" then the problem of your laptop is either a faulty eDP cable that its cables have broken from their plugs that go to the mainboard or screen or the actual mainboard or screen eDP plug is shorted/burned, as these two components are the major causes of why you don't get an image. The below are the eDP cable/plug and Screens for your PH317-55s laptop that you need to look at and/or replace, which I'm surprised that the computer repair shop didn't look at or relaced?

Note: before you do any work on the eDP cable and its plugs and/or the screen make sure that you FIRST DISCONNECT the main battery from the mainboard, as if you don't, you will cause damage to your laptop's graphics.

eDP cables - check which screen you have as the PH317-55 came with either a 144/165/240Hz refresher rate screens:

Check the eDP plugs 40 pin video connectors, if they are not burned/shorted at either the mainboard end or the screen end, shown below is the eDP plug at the screen end:

The below list is the LCD Screens fitted by Acer to the PH37-55 laptops, highlighted sections are the screen part number. The best way and if you need to replace the screen, is to see the exact screen part number that your PH317-55 has, and then match that number with a new screen, also and if you have a 144Hz/165Hz refresher rate screen, you can upgrade the top of the range 240Hz screens for better image quality, good luck and hope this solves your problem.

Its my pleasure to assist you and its even more rewarding when a community member like you awali is so grateful, thank you and anything else don't hesitate to ask, cheers👍😀

Here is a PDF extract from the Predator Helios 300 - PH317-55 SG for the LCD Panel and eDP Cable Removal for your information, follow these steps and you can't go wrong. Just so additional info, when you get to the screen where the eDP plug is, check if the mainboard plug or the eDP is not shorted in any way and/or its pins are not damaged or the eDP cables power/data strands are not disconnected from the plug, as that happens with these wires as they are very delicate and small, good luck and hope you sort the problem out.

No problems, glad to help you out. But be aware when you replace a screen, as allot of users think that you can just replace a screen of a laptop by just taking the bezel off and taking the screws and double sided tape off and disconnecting the screen plug and then reconnecting the new screens and plug and reglueing the new screen, which is WRONG and should NOT be done, as if you do that, you are going to cause serious damage to the laptops mainboards components like its chipset or gpu or cpu, so be aware of this!

I've seen laptop chipsets completely burned out like a bomb has hit them from a screen replacement that the user didn't disconnect the charger and main battery, as when you do this, the full 19.5v get injected into these components and they burn out. I hope that is not what happened to your mainboard. So always be aware of that with a screen replacement and if you are going to replace the mainboard and replace the screen on this laptop.