For sale is a premium, highly uniform workshop block of 17 genuine vintage Mitsubishi ceramic windowed EPROMs. Manufactured in Japan, these matching architectures (featuring M5L27128K and M5L27256K variants) are highly sought after by arcade PCB restorers and retro-computing hobbyists who want original, high-quality Japanese legacy silicon.

Perfect for Golden Age arcade game board programming, pinball motherboard maintenance, and vintage 8-bit/16-bit computer preservation. 17 Pieces of 28-Pin Ceramic Windowed DIP (CDIP-28) featuring highly desirable, stable 128K and 256K configurations with beautiful, clear quartz erase windows. All 17 clear windows are structurally sound and with zero cracks, scratches, or compromised seals. They have been safely housed directly inside rigid plastic carries to protect the pins. See photos for the industry standard brands Augat and Robinson Nugent (RN). Sold strictly AS-IS due to vintage semiconductor nature. Fast, next day shipping!