No display after meson replacement.
No touch so I did the obvious. Afterwards I've got no image, but I do have backlight. What should I check?
Step 1: connect to iTunes and see if it is recognized and if in DFU mode. If yes, do the obvious. Extra credit if you can salvage data. I would be able to in most cases.
Step 2: if not in DFU mode, remove Meson and test the phone without that chip.
Step 3: dig out everything around the connectors, check for resistors and filters that may have lifted. Then test the voltage drop to ground on the connector and compare to known good or a cheat sheet.
N.B.: you can invert Steps 2 and 3 and do whichever you prefer first. I'd start with 3 personally.
Step 4: check main power rails for shorts then for the proper voltages. Then the pull-up resistors for the same.
Good luck hunting. I charge expensive for Touch IC repair for exactly this. Most are done in 30 minutes including reassembly. Then some of them stay on your bench for 1 week.