at my wits end.. controllers dont charge or get recognized by pc.

i have 2 ds4 controllers, both with the same problem. ive searched google and these forums and i couldnt find anyone else with the same problem. which is odd because ive had this issue with 2 of 6 damaged controllers ive taken in, so it must be somewhat common.. il walk you through everything ive tried to do to troubleshoot the issue.

TL;DR

controllers dont react to being plugged into the ps4 system. no charging, no yellow light, no syncing, computer does not even register anything was plugged in when i plug it into my pc. charging port board plus ribbon cable nor the battery dont seem to be the issue.

controller 1 (second generation controller)

• was given to me by the previous owner and he said he couldnt get it to turn on.
• pressing the ps button didnt turn it on and pluging it in didnt show signs of life.
• took it home and tried a new battery which was known to work. nothing changed.
• took controller apart and noticed some greenish colored (corroded?) gunk on the pbc.( possible water damage?)
• wiped the corroded looking gunk off with some 90% alcohol and a Qtip.
• reasembled and pressed the ps button and we got white flashing light.(this means it looking for its console to connect correct?)
• pluging the controller into the ps4 via usb port doesnt seem to do anything.
• no yellow charging light. and not syncing with system when ps button pressed.tried different usb cable and that didnt help. plus all usb cables work with my other controllers
• pressed reset button on back of controller. no change, hold reset button for 15 seconds, no change
• when plugged into my computer, my pc doesnt recognize that anything has been plugged in, (no chime, no pop up message, nothing in my devices and printers)
• i have proper drivers installed as i regularly use my other ds4 controllers to play games on pc
• my immediate thought is the usb port must be dead. so i buy another 12 pin green usb port and ribbon cable
• does not seem to be the issue
• give up and declare the controller dead

controller 2 ( first generation controller)

• get controller from previous owner (different guy, gave me two controllers and said the batterys are dead)
• gives me pimped out controller in gold coloured shell and worn out gold buttons.
• replace battery with known working battery and press ps button. white light flashes looking for paired console.
• plug into ps4 via usb cable.
• does not sync, no yellow charging light, no signs of being plugged in.
• press reset button, no change. hold reset button for 15 seconds, no change.
• plug into my computer via usb cable. computer does not recognize anything is plugged in. (no yellow light, no sound notification, nothing added to my devices and printers, ds4windows tool does not detect anything plugged in,
• swap usb port board with known working controller. (controller3= normally working controller)
• controller 2 motherboard and front housing plus controller 3 backshell and usb port. shows same results as above.
• controller 3 motherboard and front housing plus controller 2 backshell and usb port, works as intended, no issues found,
• this should eliminate the usb port and ribbon cable from being cause of issue.
• no signs or water damage or that green gunk from before on the board.

so this is where im at.. i have no idea what to try from here. im hoping some super genius in here can lend me a hand in resolving the issue. thanks in advanced for anyone who read this novel of a problem. and thanks to anyone willing to give suggestions.