Coin Meter (Sega Mega-Tech) Updated Mar 15, 2026 · 1 min read · 0 viewing Previous Audio Circuit (Sega Mega-Tech) The audio circuit on the Sega Mega-Tech is identical to the Mega Drive, except for the final stage. ... Next Button Interface (Sega Mega-Tech) The IC24 I/O Expander connects the SMS Z80 data pins through to the CN2 (Select Buttons) and CN4 (Pl...