Topic: Purchased an original 3DS XL with a "Display issue" questions..

So I purchased another 3DS XL from ebay with a "display issue" it turns on blue light stays on and no backlight sound or screen turning on. It also charges as normal.

Here is what I have done so far based on what I have read online:

Took it apart and cleaned all contacts and inspected all contacts that are within view - no change
Re-seated all ribbon cables - no change
removed mother board and tested it in another known working 3DS XL and the board works fine
Purchased a new bottom touch screen installed that and still nothing
There is no turning on popping and shutting down. Battery tests at 3.7 V when fully charged

Only thing I can think of is I had a cut right trigger flex cable and replaced it with one from a original 3ds and nothing has changed.

Also there is case damage under above the right trigger so while the hinge still clicks there is a plastic piece which would normally hit against the actual case this plastic piece does come out a little when clicking the hinge to open or close the system. I do not think that has anything to do with it.

Questions:

Would the cable be causing this?
I have tried using a SD card and testing to see if it was soft modded but nothing comes up on the screen in a recovery mode. Have tried recovery mode as well nothing.

Checked upper screen by removing the top lid and everything seems to be intact, no breaks or solder joints that are bad from what I can see with jewelers glasses.

Have also now tested a memory card with boot. Firm and nothing not sure if custom firmware because the board worked fine in a known working 3ds xl