EPROM

EPROMs are re-writable ROM chips, generally used for SNES prototypes. To erase them, you can use UV light on the window. Due to this, EPROMs with uncovered windows are inherently prone to damage.

M27C4001

Chip type: EPROM

Part #: M27C4001

Size: 0x80000

Manufacturer: STMicroelectronics

Date format: xYWWxx

Variables: Full part #, Date code, written label

D27C80010-12

Chip type: EPROM

Part #: D27C80010-12

Size: 0x80000

Manufacturer: NEC

Date format: YYWWxxxxx

Variables: Date code, written label