Mostek MK38P70/02H DEV CPU Microcontroller, Piggyback 2716 EPROM gold Unused. It takes a 2716 eprom in the bottom pins and interfaces with the built in CPU. You can check out a project development board here https://www.pcbway.com/project/shareproject/Mostek_s_3870_development_board_c47e941f.html These are unused still in the factory tubes here in my own stock in the USA. We do not sell Chinese counterfeit junk.
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