Ipad Air 1st Gen LCD not working after Lightning Connector replacement
So my gf's iPad Air A1475 suddenly stopped accepting power charge and no computer recognized it. Apple would charge $300+ to repair it with a new one being quoted at $370+, so she allowed me to try and fix it. This was my first time attempting electronic repair but I'm a fairly capable dude so I researched as much as I could before going about opening it.
We tried hard resetting it and all with no luck - whenever you plugged a cable into the Lightning port the battery symbol appeared on the screen, blinking red but never actually charging. I now feel this was probably rash of me but I ordered a new Lightning Connector and replaced it on the logic board using plenty of flux (channeling my inner Rossmann) which I cleaned with isopropyl.
Reassembled with care and attempted to charge with no luck, now the LCD didn't come on. I did use the alcohol on the LCD-connector on the logic board as a bit of flux had gotten smeared on it - this is one of those things I think might be the cause of this.
Another might be the fact that a flex cable from the power button was slightly ripped when I either took it off or put it back in, but I still believe the LCD should have shown the charger going in.
Checking with a multimeter I can see the battery is accepting power when the cable is connected to a wall socket, but the Ah of the Lightning port itself is a mere 0,44Ah, which according to some sources should be around 2,0.
Apologies for the long question, but any insight would be invaluable (the status of the iPad in my gf's eyes is that it's dead, but I'd still like to try and find out what's wrong and hopefully fix it).