EPROM NATIONAL SEMICONDUCTOR NM27C256Q 150nS (CMOS 256K 32K x 8 ) USED

Oh yes these are used devices but they have been removed from service very carefully (especially with respect to ESD)

National Semiconductor

CMOS

Type: NM27C256Q 150

256K (32K x 8)

150nS speed

These are used, previously programmed. Although they were partially UV erased, it would be wise to erase them thoroughly and start your loading your new program into the device then placing a UV light proof label over the quartz window.

If you should need datasheets, these are available (by request)

Cleaned the window, removed from sockets and handled under tight ESD safety conditions - now stored on ESD foam.