Nintendo NES

Mainboard Revisions

PCB revisions run from NES-CPU-01 to -11.  Revisions below -05 will have noticeably poorer video output than later revisions.  Revisions -10 and -11 use circuitry to try to defeat the lockout defeaters of the unlicensed cartridges.  

NES-CPU-02 - 2A03E/2C02E-0

The original US release of the NES (fewer than 10,000 were made).

• 1985 copyright on PCB
• VRAM and WRAM are NDIP-only
• 3193 Non-A CIC

NES-CPU-03

• Unreleased

NES-CPU-04 - 2A03E/2C02E-0

• 1986 copyright on PCB
• VRAM and WRAM are NDIP-only
• 3193 Non-A or 3193A CIC
• some have a 74HC139 at U3 instead of 74LS139

NES-CPU-05 - 2A03G/2C02G-0

• 1986 copyright on PCB
• VRAM and WRAM are NDIP-only
• 3193A CIC

NES-CPU-06 - 2A03G/2C02G-0

• 1987 copyright on PCB
• VRAM and WRAM are NDIP or DIP

NES-CPU-07 - 2A03G/2C02G-0

• 1987 copyright on PCB
• VRAM and WRAM are NDIP or DIP

NES-CPU-08 - 2A03G/2C02G-0

• 1989 copyright on PCB
• VRAM and WRAM are NDIP or DIP

NES-CPU-09 - 2A03G/2C02G-0 or 2A07/2C07-0

• 1987 copyright on PCB
• VRAM and WRAM are NDIP or DIP

Has one resistor between CIC pin and cart connector to prevent CIC stun attacks

NES-CPU-10 - 2A03G/2C02G

• 1987 copyright on PCB
• VRAM and WRAM are NDIP or DIP

Has two resistors between CIC pins  and cart connector to thwart more CIC voltage stun, some later revisions have a diode to nearby GND vias as well to prevent the -5V attack

NES-CPU-11 - 2A03G/2C02G or 2A07[A]/2C07[A]

• 1987 Copyright on PCB
• VRAM and WRAM are NDIP or DIP

Has two resistors and two diodes between CIC pins, cart connector and GND to prevent CIC stun and -5V attacks