28C256 to 27C256
28C256 to 27C256 adapter
This is an adapter PCB to plug a 28C256 into a socket that expects a 27C256 or a mas rom.
The 28C256 is (re)programmable without needing a test clip, by virtue of on-board jumpers to switch the pinout between 27C256 and 28C256. IE, the board is also it's own programming adapter.
How to do the DIP legs