Vintage 1980's 27C512 eprom (erasable programmable read only memory). Model TMS27C512-2JL. Very common eprom in arcade games. These are pulled from old boards, cleaned, erased with UV light and blank checked. Our eprom programmer also does a "pin check" for open/shorts. We also verify the chip is real by checking the internal manufacturer ID code. Not fakes that have been re-labeled.