IC7
OKI MSM54C864
64K × 8 multiport (dual-port) DRAM: the 64 KB video RAM used by the VDP inside the 315-5660.
Other components on Sega Mega Drive II (Model 2) VA1 — PAL
About this component
Holds the tile patterns, name tables and sprite table that the VDP draws from. Model 2 VA1 boards replaced the two VRAM chips of the VA0 with this single 64 KB part. Faulty VRAM usually shows as corrupted or missing graphics, garbled tiles, or a blank screen with sound still playing. Sources: https://consolemods.org/wiki/Genesis:Motherboard_Differences , https://www.copetti.org/writings/consoles/mega-drive-genesis/
Pinout & readings
No pinout or reference readings yet — these show what each pin does and what a healthy part should measure.