I wouldn’t think you’d need to change out the mother board, I think a new Hard Drive would suffice. I don’t know how much you paid, but this could be an opportunity to upgrade to an SSD.
Follow the below steps to setup the new drive to use for ps4,
# Using a PC or Mac, create a folder named "PS4" on a USB drive formatted as FAT32. Inside that folder, create another folder named "UPDATE".
# Visit the ++PS4 system software update page++ and select the "Reinstall system software" section. Download the installation file and save it in the "UPDATE" folder. Save the file as "PS4UPDATE.PUP".
# Plug the USB drive containing the installation file into the PS4 console.
# Start the PS4 console in Safe Mode: press and hold the power button, releasing after the second beep.
# Select Safe Mode option 7: '''Initialize PS4 (Reinstall System Software)'''.
# Select '''Update from USB Storage Device''' > '''OK'''.
If your PS4 console does not recognize the update file, check that the folder names and file name are correct. Enter the folder names and file name using uppercase letters.