iPad Pro 11" (2018, A1980) Water Damage – Board or Battery Issue?

Hi everyone,

I need some guidance regarding my iPad Pro 11" (2018, model A1980) which suffered a water incident about 1-2 years ago. I just tried to power it on after a long time, and here’s the situation:

Symptoms / Observations:

• The iPad initially did not respond at all.
• I used an FNB58 USB tester to monitor charging.
• After cleaning some corrosion at the USB-C port with 99% isopropyl alcohol:
  • Initially drew ~0.08 A at 5 V (minimal current).
  • After a hard reset and leaving it connected, it briefly reached 15 V / 1 A → iPad made the charging chime, but it did not start and is not detected by a Mac.
  • Currently, I cannot get it back to 15 V / 1 A. It stays at 5 V / 0.08 A, and when performing a hard reset combination, it briefly goes to 5 V / 0.5 A for a few seconds, then drops back.
• USB-C port had minor green/blue corrosion, cleaned.
• iPad reacts to PD negotiation sometimes, but cannot maintain the higher voltage/current.

Other notes:

• Hard resets can temporarily change the current, but it never boots.
• I suspect the battery may be too deeply discharged or damaged.

Questions:

1. Given the PD behavior and charging currents, does this point to just a failing battery, or could the logic board be damaged?
2. Is it worth attempting a USB-C port replacement, or would that not change the current behavior?
3. Are there any safe ways to get it to stabilize at 15 V so I can see if it will boot?
4. Any other tests you would recommend before considering a battery or board replacement?

Thanks in advance for any guidance – I can provide photos of the port and FNB58 readings if needed.