Unidentified Integrated Circuit - NEC 24 Prong
The question has insufficient information for a definitive answer, a photo would help.

Going by the description of it being a 24-pin device, and that it was socketed (which implies DIP, and also suggests replacement being a maintenance option), it could be this NEC ROM device: nMOS μPD2364, 64 kilobit, 5 Volt TTL ROM, programmed at fabrication by the manufacturer.