I tried a new (working) controller board of the exact same type
The small amount of liquid was spilled onto drive in the SATA connector area. The liquid mostly affected the 15-pin power connector, and caused a short circuit local to that area. The short circuit did not cause the power supply to fail (was probably not a complete, zero Ohms short circuit). The liquid spill happened while drive was unattended and while the computer was in the sleep mode. The liquid short circuit probably had lasted for a few hours causing the connector's plastic heating and slightly melting at the connector, also damaging to two of the copper pins on the SATA connector and some corrosion on PCB. The liquid was isolated to just SATA connector area. Tested surface mount fuses on PCB with Ohmmeter, and they appear to be open-circuit (fuses SK1, SK3, SK4).
We obtained a new (working) controller board of the exact same type and tried it on the drive. Drive spins up OK, but is not recognized by the computer. The new controller PCB is exactly identical except for code number on U1 (firmware IC??). We have enclosed the new PCB along with the drive -- you may use it for repair or parts for this repair.
We would prefer that you are able to repair this drive and make it fully operational again, but we have also enclosed an additional hard drive that you can use to copy the recovered data to. We would prefer that all of the data be recovered, but the most important data should be prioritized (as noted above). Thank you!