Nintendo Entertainment System
The Nintendo Entertainment System (NES), released in Japan as the Family Computer (Famicom), is an 8-bit third-generation home video game console developed and manufactured by Nintendo. It launched in Japan on 15 July 1983 and reached North America, Europe and Australia over the following four years. It is the machine that re-established the home console market in North America after the 1983 crash, and its library — Super Mario Bros., The Legend of Zelda, Metroid — defined a generation of game design.
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| Top: NES Control Deck Bottom: Family Computer ("Famicom") | |
| Specifications | |
|---|---|
| Developer | Nintendo Research & Development 2 |
| Manufacturer | Nintendo |
| Type | Home video game console |
| Released | Release dates:JP: July 15, 1983 • NA: October 18, 1985 • EU: September 1, 1986 |
| Discontinued | Release dates:JP: September 25, 2003 • NA: August 14, 1995 • EU: 1995 |
| CPU | Ricoh RP2A03 (NTSC) / RP2A07 (PAL), MOS 6502 core with integrated audio, 1.789773 MHz (NTSC) / 1.662607 MHz (PAL) |
| Memory | 2 KB work RAM, 2 KB video RAM; cartridges may add more |
| Storage | ROM cartridge, with bank-switching mappers extending the address space |
| Display | 256×240 px; 64-entry palette table, up to 25 colours on screen at once |
| Sound | 5 channels (2 pulse, 1 triangle, 1 noise, 1 DPCM) in the CPU; Famicom cartridges may add expansion audio |
| Graphics | Ricoh RP2C02 (NTSC) / RP2C07 (PAL) PPU; 64 sprites, 8 per scanline |
| Power | NES: NES-002, 9 V AC. Famicom: HVC-002, 10 V DC, centre negative |
| OS / Firmware | None |
| Predecessor | Color TV-Game series |
| Successor | Super NES / Super Famicom |
| Model no. | NES-001 (front loader), NES-101 (top loader), HVC-001 (Famicom), HVC-101 (AV Famicom) |
For repair and servicing, start with Nintendo Entertainment System General Maintenance. The Famicom is a different board with different designators and a different power supply, and has its own pages: Nintendo Famicom General Maintenance, Nintendo Famicom Troubleshooting Guide and Nintendo Famicom Capacitor Replacement Guide.
Architecture
editThe CPU is the Ricoh RP2A03 on NTSC machines and the RP2A07 on PAL machines: a MOS 6502 core with the decimal mode disabled, plus the audio processing unit and the controller port logic on the same die. The NTSC part runs at 1.789773 MHz and the PAL part at 1.662607 MHz.
Because the audio and the controller ports are inside the CPU, a CPU fault can present as silence, or as dead controllers, with the picture intact. There is no separate sound chip to replace.
The master clock is 21.47727 MHz on NTSC and 26.601712 MHz on PAL. The NES derives its colour from a master clock six times the colour subcarrier, which is why the PAL figure is about 24 % higher rather than an arbitrary number.[1] On the NES-001 the master clock is generated at X1 and fed to the CPU's clock input at pin 29; the CPU divides it internally by twelve and presents the CPU clock at pin 31.[2][3]
Memory
edit2 KB of work RAM and 2 KB of video RAM, as separate 2K×8 static RAMs at U1 and U4 on the NES-001.[3] Cartridges routinely add their own RAM and a mapper to bank-switch program and character ROM beyond what the CPU can address directly. Save data, where a game has it, lives in battery-backed SRAM inside the cartridge — not in the console.
Graphics
editThe RP2C02 picture processing unit (RP2C07 on PAL) drives a 256×240-pixel display from tile-based backgrounds and hardware sprites, with 64 sprites available and a hard limit of 8 per scanline — the cause of the sprite flicker the machine is known for. The palette is a 64-entry table, several of whose entries are duplicates. The console's palette RAM is 32 bytes arranged as four background and four sprite palettes of three colours each, sharing one backdrop colour, so at most 25 colours can be on screen at once.[1]
Sound
editFive channels inside the CPU: two pulse, one triangle, one noise and one delta-modulation channel for sample playback. Audio leaves the RP2A03 on pins 1 and 2 (AD1 and AD2).[3] Famicom cartridges can drive additional sound hardware back into the console through the cartridge connector; the NES's 72-pin connector does not carry that path, which is why expansion audio titles sound different on the two machines.
Input, output and expansion
editTwo controller ports, detachable on the NES and wired into the shell on the Famicom — although even on the Famicom each controller ends in a connector that plugs into the mainboard, and Nintendo treats controllers as a swap-out repair.[4] The controller shift register (a 4021) is inside each controller, not on the console mainboard.[4]
The cartridge interface is 72-pin on the NES and 60-pin on the Famicom. On the NES-001 cartridge edge connector, VCC is pin 36 and ground is pin 72.[2] The Famicom adds a 15-pin D-sub expansion port on the front for peripherals, and a microphone in controller 2.[4]
Power
editThe two machines take incompatible supplies, and this is the single most destructive mistake made with them.
| Machine | Adapter | Output | Notes |
|---|---|---|---|
| NES-001 and NES-101 | NES-002 | 9 V AC | Rectifier, reservoir and regulator are all inside the console. A high off-load reading is normal — it is a bare transformer |
| Famicom (HVC-001) | HVC-002 | 10 V DC, centre negative | Nintendo specifies a no-load output of 13.5 ± 1.5 V as normal; the on-board 7805 takes 13–14 V in and gives 5 V out[4] |
Both machines run everything from a single +5 V logic rail. Neither has a +12 V rail.
Servicing
edit| Topic | Page |
|---|---|
| NES preventive care, chip map, test points | Nintendo Entertainment System General Maintenance |
| NES fault-finding | Nintendo Entertainment System Troubleshooting Guide |
| NES capacitors, by module | Nintendo Entertainment System Capacitor Replacement Guide |
| Famicom preventive care | Nintendo Famicom General Maintenance |
| Famicom fault-finding | Nintendo Famicom Troubleshooting Guide |
| Famicom capacitors | Nintendo Famicom Capacitor Replacement Guide |
Documents hosted here: NES-001 Schematic, Nintendo Famicom Service Manual, Nintendo World Class Service NES Product Maintenance Troubleshooting And Service Guide and the NOA Independent Servicer Technical Training Workbook. The original Nintendo NES motherboard schematic set is at File:NES Schematics.pdf.
Motherboard images
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NES-001 (front-loader) mainboard -
Famicom HVC-CPU-07 mainboard
Schematics
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Cartridge, controller and Zapper -
Controller ports -
CPU, PPU, RAM and CIC -
Power, AV and RF switch
Gallery
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Nintendo Entertainment System with controller -
Family Computer (Famicom) -
NES controller -
Famicom controllers I and II
Related pages
editReferences
edit- ↑ 1.0 1.1 NESdev Wiki, PPU variants — https://www.nesdev.org/wiki/PPU_variants , and PPU palettes — https://www.nesdev.org/wiki/PPU_palettes . Source for the 21.477272 MHz NTSC and 26.601712 MHz PAL master clocks and their relationship to the colour subcarrier, the RP2C02 / RP2C07 part numbers, the 64-entry palette table, and the 32-byte palette RAM layout of four background and four sprite palettes of three colours each sharing one backdrop entry, from which the 25-colour on-screen maximum follows.
- ↑ 2.0 2.1 Nintendo, NES Motherboard schematic set, document NESMB1.SCH, Rev. A, 12 July 1989, hosted at File:NES Schematics.pdf. Sheet 1: U10 (NES CIC) pin 6 CLK, pin 7 RES IN, pin 9 RES OUT, pins 1/2/10 CIC1/CIC2/CIC10 to the cartridge and pins 11–15 to ground; Y1 a 4 MHz crystal with R1 1 MΩ and sections of U9 (74HCU04) forming the CIC clock oscillator; the RP2A03 clock input at pin 29 labelled MC and fed from the 21.4772 MHz master clock, with PHS2 at pin 31; cartridge edge connector pin 36 VCC and pin 72 GND.
- ↑ 3.0 3.1 3.2 NES-001 Schematic (Electronix Corp. redraw by N. Schenk), hosted at File:NES-001.pdf. Source for the RP2A03 and RP2C02 pin assignments, the U-number allocation, the 21.47727 MHz crystal at X1, and the capacitor designators and values on the control deck PCB — C1 100 µF, C9 2.2 µF and C23 1 µF electrolytic, with C6/C7 at 220 pF and the C10–C25 run at 0.01 µF, all ceramic.
- ↑ 4.0 4.1 4.2 4.3 Nintendo, ファミコン・スーパーファミコン・ゲームボーイ サービスマニュアル (Famicom / Super Famicom / Game Boy Service Manual), issued 7 August 1992, hosted at Nintendo Famicom Service Manual. HVC section, pp. 2–10: AC adapter rated DC 10 V with a normal no-load output of DC 13.5 ± 1.5 V; HVC power-circuit block diagram showing a 7805 with 13–14 V in and 5 V out, drawn in both the standard and the VCCI variant; RF switch terminal carrying DC 5 V in game mode; the three solder points that need reinforcing around the DC jack; "before you decide it is a fault" table, p. 3; controller fault symptoms and the plug-in controller connectors, p. 4; exploded parts diagrams, pp. 7–9; Famicom repair price list, p. 10 (60-pin card connector, 15-pin D-sub jack, crystal, RF modulator unit, DC jack, 7805 three-terminal regulator, fuse listed for VCCI boards only, electret microphone, CMOS 4021 and 4069 in the controllers). SHVC section, pp. 11–15: power-switch harness polarity; SHVC power circuit, 7805 with 13–14 V in and 5 V out; Super Famicom repair price list (1.5 A SSTR axial fuse, 7805, 62-pin card connector in upper and lower halves, sound module).