NES-001 (9V AC Bridge Rectifier) vs. Famicom (9V DC Centre-Negative Only!) Power Trap

The original front-loading North American / European NES-001 and top-loading NES-101 include an internal full-wave bridge rectifier inside their power stage — meaning they safely accept 9V AC (from the original NES-002 transformer) OR 9V–12V DC of EITHER polarity! However, the Japanese Famicom (HVC-001), AV Famicom (HVC-101), and Famicom Disk System RAM Adapter have NO bridge rectifier and strictly require 9V–10V DC Centre-Negative! Plugging an original 9V AC NES-002 brick into a Famicom or Super Famicom sends raw alternating current into the filter capacitor and 7805 regulator, blowing both within seconds!

1 Power Polarity Matrix by Model

Console Model	Accepted Input	Plug / Polarity
NES-001 / NES-101 (US/EU/UK)	9V AC or 9–12V DC (≥850mA)	5.5×2.5mm (Any Polarity — internal bridge)
Famicom HVC-001 / AV HVC-101	9V–10V DC ONLY (≥850mA)	5.5×2.1mm (Centre-NEGATIVE ⊖)
Twin Famicom (Sharp AN-500/505)	7.6V DC Regulated (1.25A)	EIAJ-03 (Centre-POSITIVE ⊕)

2 RF/Power Box 2200µF Hum-Bar Recap

Rolling Dark Horizontal Bars & 60Hz/50Hz Buzz: Inside the soldered tin NES-001 RF/AV/Power box sits a single 2200 µF 16V/25V radial electrolytic capacitor right after the bridge rectifier.
After 35+ years next to the hot AN7805 heatsink, this capacitor dries out, allowing 100Hz/120Hz ripple into the +5V rail and PPU video amplifier.
Recap Checklist: Replace the main filter cap with a 2200 µF or 3300 µF 25V 105°C Panasonic FR/FC, plus the three 100 µF / 10 µF decoupling caps on the motherboard.

3 2C02 PPU has NO Native RGB Output!

Unlike the Sega Master System or SNES, the standard retail Ricoh RP2C02 (NTSC) and RP2C07 (PAL) Picture Processing Units generate Composite Video directly inside the silicon die — Pins 14–16 are Slave EXT inputs, not RGB!
To get true RGB, S-Video, or Component out of an NES/Famicom, install Tim Worthington's NESRGB kit, which sits between the motherboard and PPU to intercept digital palette data before the internal composite DAC.

Architectural Summary & Hardware Revisions

Dual-bus Harvard-style split architecture: CPU/APU bus ($0000–$FFFF) and PPU CHR/VRAM bus ($0000–$3FFF) routed simultaneously to every cartridge.

CPU & Audio (APU) Ricoh RP2A03 (NTSC 1.789773 MHz) / RP2A07 (PAL 1.662607 MHz) — MOS 6502 core (no BCD mode) + 5-ch APU (2 Pulse, 1 Triangle, 1 Noise, 1 DPCM)

Video (PPU) Ricoh RP2C02 (NTSC 5.369 MHz) / RP2C07 (PAL 5.320 MHz) — 256×240 resolution, 64 sprites (8 per scanline), 25 simultaneous colours from 54-colour palette

System & Video RAM 2 KB Internal Work RAM (6116 SRAM at $0000–$07FF) + 2 KB Internal Nametable VRAM (6116 SRAM) + up to 8 KB WRAM (6264) on Cartridge

Cartridge & Mappers 72-Pin NES ZIF (32KB PRG + 8KB CHR base; expanded via MMC1, MMC3, VRC6/7) / 60-Pin Famicom (adds Pin 45->46 External Expansion Audio mix!)

Front-Loading NES-001 1985 – 1993 • 72-Pin ZIF + 10NES CIC

To distance the NES from the 1983 North American video game crash, Masayuki Uemura redesigned the Famicom with a VCR-style zero-insertion-force (ZIF) spring tray, a 72-pin double-bend edge connector, and the 4-bit Sharp SM590 10NES CIC lockout chip (U10). When the 72-pin connector's nickel-plated spring fingers lose tension or tarnish, the console CIC cannot handshake with the cartridge CIC, resetting the CPU/PPU at 1 Hz (the infamous blinking red power LED).

Key Motherboard Revisions (NES-CPU-01 to NES-CPU-11)

NES-CPU-01 to -03: Early boards with glitchier RP2A03E (lacks looped periodic noise) and non-socketed 2KB SRAMs.
NES-CPU-07 (Most Common): Uses RP2A03G and RP2C02G-0; ideal candidate for NESRGB and 2200µF RF box servicing.
NES-PAL-001 / Mattel / NES-Version: Uses RP2A07 CPU and RP2C07-0 PPU with region-specific CIC (3195A Europe / 3197A UK/Italy/Australia) and controller port protection diodes.

72-Pin ZIF Connector Restoration & CIC Pin 4

Component / Area	Bench Procedure
Original 72-Pin ZIF	Remove the 72-pin connector, boil it in distilled water for 10 minutes to float out skin oils/flux, scrub contacts with 99% IPA, and gently lift each bottom-row pin upwards by 0.5mm with a precision dental pick (genuine boiled Nintendo connectors outlast stiff aftermarket clones!).
10NES CIC Pin 4 (U10)	On `NES-CPU-04` through `-11`, lifting Pin 4 of U10 (`3193A` / `3195A` / `3197A`) and tying it to Ground converts the console CIC from "Lock" to "Key" mode, disabling the 1Hz reset and making the console region-free (better yet: install a NullCIC or switching region mod).
Expansion Audio (Pin 54)	To hear VRC6/VRC7/FDS expansion audio on an NES-001 via an EverDrive N8 Pro, solder a `47 kΩ` resistor between Expansion Port Pin 3 (Audio In) and Pin 9 (EXP 6 / Cart Pin 54)!

Original Famicom (HVC-001) & AV Famicom (HVC-101) 60-Pin Direct Slot • Cartridge Audio Mixing

The Japanese 60-pin Famicom omits the 10NES CIC lockout chip completely and routes the console's internal 2A03 audio out to Cartridge Pin 45 and back in on Cartridge Pin 46 — allowing Konami VRC6 (Akumajou Densetsu), VRC7 (Lagrange Point), Namco 163, Sunsoft 5B, and the Famicom Disk System to mix extra synth channels directly into the console's audio output!

Original HVC-001 (1983): Hardwired Player 1 & 2 controllers (with Microphone on Controller 2 mapped to $4016 Bit 2), front 15-pin DA-15 expansion port, and RF-only output (requires a 2SA937 / THS7314 AV mod to get Composite video).
AV Famicom HVC-101 (1993 "New Famicom"): Top-loading 60-pin shell with two standard NES 7-pin controller sockets, the 15-pin Famicom expansion port, and a standard 12-pin Nintendo Multi-Out port with the cleanest factory composite video of any 8-bit Nintendo console!

HVC-001 Composite Mod & PPU Pin 21 Jailbar Fix

Early HVC-001 boards route the 2C02 PPU's Pin 21 (Video Out) directly across digital address traces, causing faint vertical jailbars:

Lift PPU Pin 21 slightly from the motherboard pad, solder a 2SA937 (or 2N3906) PNP emitter-follower buffer directly onto the PPU pins (Emitter to Pin 20 GND via 150Ω, Collector to GND, Base to Pin 21), and wrap a 4.7 µF tantalum decoupling capacitor directly from PPU Pin 40 (+5V) to Pin 20 (GND).
Player 2 Microphone Hum: If an original HVC-001 outputs a constant buzz even when no buttons are pressed, clean the dirty sliding volume pot on Controller II with DeoxIT F5 — a noisy mic slider triggers $4016 Bit 2 and leaks into the analog audio path!

Top-Loader NES-101 & Famicom Disk System (HVC-022) 1993 Redesign & Quick Disk Drive

While the Japanese AV Famicom (HVC-101) received a Multi-Out A/V port, the North American top-loading NES-101 was cost-reduced to RF-only output and suffered from severe vertical jailbar lines due to poor PCB trace routing between PPU Pin 21 and the RF modulator. Meanwhile, the Famicom Disk System (FDS) uses a Mitsumi 2.8″ Quick Disk mechanism with a notorious rubber drive belt and spindle alignment requirement.

FDS Drive Belt & Error 21 / 22 / 27 Calibration

FDS Error 01 (Battery) / Error 02 (Power): Check the 6× C-cell battery tray contacts or power the FDS via a 9V DC Centre-Negative adapter.
FDS Error 21, 22, 27 (Disk Read Failure): After replacing the perished 0.7mm × 69mm flat Mitsumi rubber belt, loosen the spindle hub hex screw, rotate the cam gear until the head clicks back to Track 00 (outermost stop), and fine-tune the spindle hub angle by ±2° until multi-side games load cleanly.

Diagnostic Flowcharts & Common Fault Decision Trees

Symptom-by-symptom board isolation for the NES-001, NES-101, and Famicom

⚠

1. 1Hz Blinking Red Power LED & Screen Flashing On/Off

Symptom: Power LED flashes once per second and the TV screen alternates between grey/white and black.

Diagnostic Decision Tree

Verify Cartridge Edge Fingers: Scrub both sides of the cartridge PCB edge with a white Mars Plastic eraser and 99% IPA. Four dedicated pins (Pins 34, 35, 70, 71) carry the 4-bit 10NES CIC clock and data stream!
Inspect & Boil the 72-Pin ZIF Connector: Remove the 72-pin connector, boil in distilled water for 10 minutes, and check continuity from the motherboard edge fingers through to the top cartridge slot pins.
Check 4.00 MHz Ceramic Resonator (X2): The 10NES CIC chip (U10) runs off its own dedicated 4.00 MHz ceramic resonator (X2). If X2 has a cracked leg, the CIC never boots and resets the CPU continuously.

⚡

2. Solid Grey, Blue, or White Screen (Power LED Stays Solid)

Symptom: Power LED stays solid red (no 1Hz blink), yet the screen remains a solid flat colour with no audio.

Diagnostic Decision Tree

Measure +5.0V at U1 (6116 WRAM Pin 24) & 2A03 Pin 40: If below 4.75V, replace the AN7805 regulator and 2200 µF capacitor inside the RF/Power box.
Check 2A03 CPU Pin 3 (/RST) & Pin 29 (21.477 MHz CLK): Pin 3 should go LOW briefly on power-up and stay at +4.8V. Verify M2 (1.79 MHz Phi2 clock) on 2A03 Pin 31.
Test U1 (2KB CPU Work RAM — 6116 SRAM) & U2 (74LS139 Decoder): A dead U1 6116 SRAM or failed U2 address decoder prevents the 6502 stack (`$0100–$01FF`) from functioning, freezing the CPU before the first PPU register write.

📺

3. Game Boots with Music, But Background Tiles Are Scrambled

Symptom: Game plays music and responds to controller inputs, but background graphics show random characters, vertical bars, or wrong nametable scrolling.

Diagnostic Decision Tree

Check U3 (74LS373 PPU Address Latch): The 2C02 PPU multiplexes its lower 8 address bits (PA0–PA7) with its 8 data bits (PD0–PD7) through U3 (74LS373). A faulty 74LS373 corrupts every VRAM/CHR read!
Test U4 (2KB PPU Nametable VRAM — 6116 SRAM): If sprites look clean (sprites live in internal PPU OAM) but background tiles are stuck or duplicated across screens, replace U4 (6116 SRAM).
Check Cartridge CIRAM /CE (Pin 57) & PA10/PA11 Mirroring Pins: Dirty CHR side pins on the 72-pin connector cause missing bitplanes (venetian blind lines through sprites).

🔊

4. Sound Works, No Composite Picture (or Picture Works, Dead Controllers)

Symptom: Console plays title music through the Red RCA jack, but Yellow Composite RCA is dead black (or controllers don't respond).

Diagnostic Decision Tree

No Composite Video: Probe PPU Pin 21 and the base/emitter of PNP transistor Q1 (2SA937) next to the PPU. If video is present at Q1 Emitter and 5-Pin Header Pin 5, reflow the cracked Yellow RCA jack solder joint inside the RF box!
Dead Controller Port 1 or 2: Both NES 7-pin controller ports pass through hex inverting buffers U7 and U8 (74HC368) and EMI filter arrays. Replace the corresponding 74HC368 if Clock/Latch/Data fail to reach 2A03 Pins 35/36/39.

Dedicated NES & Famicom Connector Pinouts

Click any connector below to open its interactive SVG pinout diagram, signal specs, and cable building guide

1. NES-001 RF / Composite A/V & Power Module (5-Pin Header) →

Complete 5-pin motherboard-to-RF-box header pinout (+5V, GND, Switched +V, Audio In, Video In), 2200µF hum-bar capacitor replacement, and Q1 2SA937 emitter-follower schematic.

Open Interactive Pinout →

2. NES 7-Pin Controller & Zapper Lightgun Port →

Synchronous serial CD4021B 8-bit shift register protocol (A, B, Select, Start, Up, Down, Left, Right), Zapper photodiode/trigger pins (D3/D4), wire colour table, and PAL NES diode bypass.

Open Interactive Pinout →

3. Nintendo 12-Pin Multi-Out Port (AV Famicom HVC-101 & NESRGB) →

Used natively on the 1993 AV Famicom (HVC-101) and installed on NESRGB-modded front-loaders and top-loaders for S-Video and RGB SCART output.

Open Nintendo Multi-Out Pinout →

NES / Famicom Custom Silicon & Glue Logic Reference

Click any chip card to open its interactive DIP pinout diagram in our IC Pinout Finder

DIP-40 • U1 CPU/APU

Ricoh RP2A03 / RP2A07 (6502 Core)

Second-source MOS 6502 core (with BCD decimal mode transistor trace omitted) + 5-channel PSG/DPCM Audio Processing Unit, DMA controller, and $4016/$4017 joypad strobes.

Inspect 6502 Core Pinout → DIP-20 • U3 PPU Latch

74LS373 Octal Transparent Latch

Demultiplexes the 2C02/2C07 PPU's lower 8 address bits (PA0–PA7) from its 8-bit data bus (PD0–PD7) using the PPU ALE (Address Latch Enable) strobe.

Open 74LS373 Pinout → DIP-16 • U2 Decoder

74LS139 Dual 2-to-4 Decoder

Decodes CPU address lines A13–A15 and M2 (Phi2) to generate chip selects for internal 2KB Work RAM ($0000–$1FFF), PPU registers ($2000–$3FFF), and Cartridge ROM ($8000–$FFFF).

Open 74LS139 Pinout → DIP-28 • Cart WRAM / CHR-RAM

6264 (8KB SRAM) & 6116 (2KB SRAM)

The NES motherboard uses two 2KB 6116 SRAMs (U1 CPU WRAM & U4 PPU VRAM), while cartridges like Zelda and Metroid use an 8KB 6264 SRAM for battery saves or CHR-RAM.

Open 6264 SRAM Pinout → DIP-14 • U9 CIC Inverter

74HCU04 Unbuffered Hex Inverter

Forms the 4.00 MHz crystal oscillator and reset conditioner for the 10NES CIC security microcontroller (U10) and audio amplifier stage on Famicom cartridges.

Open 7404 Pinout → DIP-28 • NROM PRG/CHR

27C64 / 27C256 EPROM

Standard 28-pin EPROMs used on NROM, CNROM, and UNROM boards (note that 128KB+ Nintendo Mask ROMs rearrange Pins 1, 2, 24, 30, 31 compared to JEDEC 27C010 EPROMs).

Open 2764 EPROM Pinout → Rust / Wasm • 6502 & ROM Lab

6502 Disassembler & ROM Patcher

Disassemble 2A03 / 6502 PRG-ROM slices, verify IEEE CRC32 & 16-bit checksums before burning 27C256 EPROMs, and apply hex patches in your browser.

Open Retro File Lab →

Capacitor & Power Stage Reference

Nintendo NES / Famicom — Capacitor & Recap Reference

Board revisions, electrolytic capacitor lists, voltage/farad ratings, and Through-Hole servicing notes.

Nintendo NES / Famicom — Printable Board Recap & Capacitor BOM ReferenceFormat this system's capacitor replacement list, diagnostic flowchart, and IC pinouts into a high-contrast bench PDF.

Nintendo NES & Famicom — NES-CPU-07 / NES-CPU-11 & Mitsumi Power/RF Module

Front-Loader NES-001, Top-Loader NES-101 & HVC-001 Famicom • Mount: Through-hole • Difficulty: Intermediate (RF box desoldering)

Full Printable Recap Sheet →

NES-001 Mitsumi Power / AV / RF Module (5 Capacitors)

Ref	Capacitance	Voltage	Package / Type	Circuit Location & Bench Notes
`C1 (Main)`	2200 uF	25 V	Radial (105 C Low-ESR)	Primary culprit for wavy hum bars on composite video.
`C2`	100 uF	16 V	Radial
`C3`	10 uF	25 V	Radial
`C4`	1 uF	50 V	Radial
`C5`	47 uF	16 V	Radial

NES-CPU-07 / NES-CPU-11 Mainboard (4 Capacitors)

Ref	Capacitance	Voltage	Package / Type
`C1`	100 uF	10 V	Radial / Axial
`C8`	10 uF	25 V	Radial
`C14`	1 uF	50 V	Radial
`C24`	2.2 uF	50 V	Radial

Printable Diagnostic Flowchart & Voltage CheckpointsFormat this step-by-step fault isolation tree into a high-contrast bench reference sheet.

Nintendo NES / Famicom — Interactive Diagnostic Flowchart & Voltage Checkpoints

Enable JavaScript to run the client-side interactive fault-isolation flowchart engine.

Complete Diagnostic Flowchart: Capacitive Load, ESR & Power Rail Ripple Diagnostic Tree (Universal Retro Mainboards (C64, Amiga, ZX Spectrum, Game Gear, Consoles))

STEP 1: Measure 100Hz/120Hz Peak-to-Peak AC Ripple on the +5V / +12V Bulk Filter Cap [node-1]

Set your oscilloscope to AC Coupling, 200 mV/div, and 2.5 ms/div (20 MHz bandwidth limit ON). Probe directly across the main bulk filter capacitor (e.g. C19 2200µF / C88 1000µF on C64, or C303/C304 on Amiga) under full system load. Measure the peak-to-peak sawtooth ripple amplitude (mVpp).

Expected Reading: < 50 mVpp clean regulated rail (post-regulator) or < 350 mVpp on raw unregulated bulk DC before the 7805/7812.

STEP 2: Check Linear Regulator (7805 / 7812) Input-to-Output Dropout Margin [node-2]

Switch oscilloscope or multimeter to DC Volts and measure Pin 1 (Input) of the 7805 (+5V) or 7812 (+12V) regulator at the bottom of the ripple trough. Verify that Input Voltage remains at least 2.0V above the regulated output (e.g. ≥7.2V into a 7805, ≥14.2V into a 7812).

Expected Reading: 7805 Input ≥ 7.2V DC; 7812 Input ≥ 14.2V DC. Below this dropout threshold, ripple punches straight through to the logic rail.

STEP 3: Check Local IC Decoupling & Audio/Video AC Coupling Capacitors [node-3]

Probe audio output coupling caps (e.g. C91 100µF on C64 SID Pin 27, or C324/C334 22µF SMD on Amiga Paula) — compare upstream vs. downstream signal amplitude. Inspect SMD electrolytic pads (Amiga 600/1200, Game Gear, DMG-01) under magnification for fishy odor, dull grey solder corrosion, or lifted copper traces.

Expected Reading: Full audio/video swing across the coupling capacitor with zero DC leakage on the output side and clean, shiny solder pads.

[ISOLATED FAULT: RES-BULK-CAP] Fault Isolated: High-ESR Bulk Filter Capacitor (>100 mVpp Rail Ripple) VERDICT

Excessive 100/120Hz sawtooth ripple on the DC rail confirms that the primary reservoir/filter electrolytics have dried out and lost effective capacitance.

[ISOLATED FAULT: RES-REG-DROPOUT] Fault Isolated: Linear Regulator Dropout / Bridge Rectifier Diode Open VERDICT

The pre-regulator DC rail is sagging below the minimum 2V dropout headroom required by the 7805/7812 regulator.

[ISOLATED FAULT: RES-COUPLING-CAP] Fault Isolated: Open/Leaky Audio or Video Coupling Capacitor & Trace Corrosion VERDICT

Signal attenuation, muffled audio, or DC offset hum across the coupling stage indicates dried-out or leaking coupling capacitors.

[ISOLATED FAULT: RES-RAILS-HEALTHY] Verification Passed: Power Rails, Ripple & Coupling Capacitors Within Spec VERDICT

All measured DC supply rails, AC ripple levels (<50 mVpp), and coupling stages pass bench specification. If performing a preventive recap, use the verified board BOM below.

Interactive Pinouts, Visualizers & Disassemblers

Nintendo NES / Famicom — System Bench Tools & IC Pinouts

Click any chip below to open its interactive DIP/PLCC pinout diagram, pin-by-pin signal table, and oscilloscope test waveforms.

Nintendo NES / Famicom — Printable IC Pinout & Chipset SummaryPrint this system's custom IC pinout summary or open any chip card below for its full DIP/PLCC pinout sheet.

DIP-14 74-Series Gates

74LS00

SN74LS00N / DM74LS00N

Quad 2-input NAND gate — the most common glue-logic part in retro computers.

Open Interactive Pinout →

DIP-14 74-Series Gates

74LS04

SN74LS04N / DM74LS04N

Hex inverter — six independent NOT gates in one 14-pin DIP, the standard logic-level converter of the 74-series family.

Open Interactive Pinout →

DIP-16 74-Series Decoders

74LS138

SN74LS138N / DM74LS138

3-to-8 line decoder with three enable inputs and eight active-low outputs — the classic memory-address decoder.

Open Interactive Pinout →

DIP-16 74-Series Decoders

74LS139

SN74LS139N / DM74LS139A

Dual 2-to-4 line decoder — two independent decoders, each with one active-low enable and four active-low outputs.

Open Interactive Pinout →

DIP-14 74-Series Gates

74LS32

SN74LS32N / DM74LS32N

Quad 2-input OR gate — same 14-pin pinout as the 74LS00, with outputs high when either input is high.

Open Interactive Pinout →

DIP-20 74-Series Bus Interface

74LS373

SN74LS373N / DM74LS373

Octal transparent latch with 3-state outputs — level-sensitive latch enable on pin 11, the standard address latch for multiplexed buses.

Open Interactive Pinout →

DIP-40 MOS 6500

MOS 6502

MOS 6502 / R6502 / UM6502

The 8-bit CPU at the heart of the Apple II, PET, VIC-20, BBC Micro and Atari 2600.

Open Interactive Pinout →

DIP-28 EPROM

2764 8K x 8 EPROM

2764 / 2764A / 27C64 / M2764A / HN482764

8K x 8 UV-erasable EPROM, the JEDEC 28-pin byte-wide standard. Same pinout as the 6264 SRAM except for four pins.

Open Interactive Pinout →

DIP-28 EPROM

27128 / 27256 EPROM & CPC 40009 System ROM

Amstrad 40009 / 27C128 (16KB) / 27C256 (32KB) / 27C512

16KB (27128) and 32KB (27256) JEDEC 28-pin ROM/EPROM — direct drop-in replacement for the Amstrad CPC 464's 32KB OS + Locomotive BASIC ROM (IC103, part 40009).

Open Interactive Pinout →

DIP-28 Static RAM

6264 8K x 8 SRAM

6264 / HM6264 / 5564 / TC5565 / UM6264

8K x 8 SRAM, the JEDEC 28-pin byte-wide standard. Two chip selects of opposite polarity — leave CS2 floating and it never responds.

Open Interactive Pinout →

Visualizer

Signal & Trace Visualizer (Scope)

Compare healthy vs. faulty CPU clocks, reset ramps, PLA strobes, and 5V PSU ripple waveforms.

Disassembler & ROM Lab

Retro File Utilities (Rust/Wasm)

6502/6510 disassembler with IC register links, C64 .D64 parser, and EPROM CRC32 verifier/patcher.

Logic & Pinouts

Connector & Port Pinout Reference

59 interactive RGB SCART, DIN A/V, PSU polarity, joystick, floppy, and expansion bus pinouts.

Logic & Pinouts

Logic & RAM Substitution Guide

Cross-reference 4116→4164 DRAM mods, 2364→27C256 EPROM adapters, and 74LS/74HCT swaps.

Workshop Rescue & Community Rehoming Free UK Shipping Never Resold

Dead Nintendo NES & Famicom on the Bench — or Clearing Out Spare Kit?

Worked through the fault checklist and found a dead custom IC, severe trace rot, or a repair you don't have the gear to tackle? Don't scrap your Nintendo NES & Famicom — donate faulty machines, donor boards, joysticks, cables, or peripherals to Smiggy's Workshop. We cover UK shipping and never resell a single item.

Donate Nintendo NES & Famicom / Parts →

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Where Refurbished Donations Go — Free to the Community

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Nintendo NES & Famicom Machine Hub

NES-001 (9V AC Bridge Rectifier) vs. Famicom (9V DC Centre-Negative Only!) Power Trap

1 Power Polarity Matrix by Model

2 RF/Power Box 2200µF Hum-Bar Recap

3 2C02 PPU has NO Native RGB Output!

Architectural Summary & Hardware Revisions

Front-Loading NES-001 1985 – 1993 • 72-Pin ZIF + 10NES CIC

Key Motherboard Revisions (NES-CPU-01 to NES-CPU-11)

72-Pin ZIF Connector Restoration & CIC Pin 4

Original Famicom (HVC-001) & AV Famicom (HVC-101) 60-Pin Direct Slot • Cartridge Audio Mixing

HVC-001 Composite Mod & PPU Pin 21 Jailbar Fix

Top-Loader NES-101 & Famicom Disk System (HVC-022) 1993 Redesign & Quick Disk Drive

FDS Drive Belt & Error 21 / 22 / 27 Calibration

Diagnostic Flowcharts & Common Fault Decision Trees

1. 1Hz Blinking Red Power LED & Screen Flashing On/Off

Diagnostic Decision Tree

2. Solid Grey, Blue, or White Screen (Power LED Stays Solid)

Diagnostic Decision Tree

3. Game Boots with Music, But Background Tiles Are Scrambled

Diagnostic Decision Tree

4. Sound Works, No Composite Picture (or Picture Works, Dead Controllers)

Diagnostic Decision Tree

Dedicated NES & Famicom Connector Pinouts

1. NES-001 RF / Composite A/V & Power Module (5-Pin Header) →

2. NES 7-Pin Controller & Zapper Lightgun Port →

3. Nintendo 12-Pin Multi-Out Port (AV Famicom HVC-101 & NESRGB) →

NES / Famicom Custom Silicon & Glue Logic Reference

Ricoh RP2A03 / RP2A07 (6502 Core)

74LS373 Octal Transparent Latch

74LS139 Dual 2-to-4 Decoder

6264 (8KB SRAM) & 6116 (2KB SRAM)

74HCU04 Unbuffered Hex Inverter

27C64 / 27C256 EPROM

6502 Disassembler & ROM Patcher

Nintendo NES & Famicom — Unified Workbench Reference

Nintendo NES / Famicom — Capacitor & Recap Reference

Nintendo NES & Famicom — NES-CPU-07 / NES-CPU-11 & Mitsumi Power/RF Module

NES-001 Mitsumi Power / AV / RF Module (5 Capacitors)

NES-CPU-07 / NES-CPU-11 Mainboard (4 Capacitors)

Complete Diagnostic Flowchart: Capacitive Load, ESR & Power Rail Ripple Diagnostic Tree (Universal Retro Mainboards (C64, Amiga, ZX Spectrum, Game Gear, Consoles))

Nintendo NES / Famicom — System Bench Tools & IC Pinouts

74LS00

74LS04

74LS138

74LS139

74LS32

74LS373

MOS 6502

2764 8K x 8 EPROM

27128 / 27256 EPROM & CPC 40009 System ROM

6264 8K x 8 SRAM

Signal & Trace Visualizer (Scope)

Retro File Utilities (Rust/Wasm)

Connector & Port Pinout Reference

Logic & RAM Substitution Guide

Theme Palette

Audio & Display

System Info