The battery terminals on the 189 love to lure leaking battery gunk along the full path.. straight to the main board, (Energizer bunnied again IIRC
)
and eat at the metal rail style terminals along the way, they corrode very easily along the entire path
Been there when I bought mine used and unaware
not pretty, but saved it, just in time...
i.e. if you see some corrosion or darkened spots on the terminals in any seller photos, even slight, you need to see the board too
A replacement battery terminals kit isn't cheap either, if you can find it
A fully working 189 is still a great all rounder meter in 2019
that's why they rarely come up for sale and or cheap