Super Nintendo (SNES / Super Famicom) Hub
16-bit Ricoh 5A22 & S-PPU / 1CHIP workbench reference — F1 1.5A Pico fuse alert, SHVC-CPU-01 vs 1CHIP-01/02/03 & Jr. board selector, S-CPU / PPU rot fault matrix, SMD capacitor checklist, and Multi-Out RGB SCART pinouts.
F1 1.5A Pico Fuse Alert, Regional Power Jacks & Leaking SMD Capacitors
Nintendo used three completely different power input jacks and rectifiers across the Japanese Super Famicom, North American SNES, and European/UK PAL SNES! Even more importantly, 80% of "completely dead" SNES / Super Famicom consoles (no red power LED) simply have a blown green axial 1.5A 125V Littelfuse Pico II Fuse (F1) soldered on the left edge of the motherboard next to the 7805 regulator — often blown by unplugging the DC power cord while the main power switch was still ON or before discharging the main filter capacitor!
1 Regional Power Input Matrix
| Region / Model | Jack Size | Required Input |
|---|---|---|
| Super Famicom (SHVC-001 JP) | 5.5×2.1mm Barrel | 9V–10V DC Centre-NEGATIVE (⊖) @ 850mA (NO bridge rectifier!) |
| US SNES (SNS-001 / SNS-101) | Proprietary 7.0×1.0mm Center-Pin | 10V DC Centre-NEGATIVE (⊖) @ 850mA (Brittle plastic barrel cracks!) |
| PAL SNES (SNSP-001A UK/EU) | 5.5×2.5mm Barrel (w/ Inner Pin) | 9V–9.8V AC (1.3A) or 9–12V DC Any Polarity (has internal bridge rectifier!) |
2 F1 1.5A Pico Fuse & 7805 Upgrade
- Always Discharge Before Working Inside: Turn the SNES power switch ON for 3 seconds AFTER unplugging the power brick so the red LED flashes once and drains the main smoothing capacitor before you remove the metal shield!
- Testing Fuse F1: Set your multimeter to continuity/ohms across the small green resistor-shaped component labeled
F1(SOC 1.5A) at the rear-left of the PCB. If open-circuit, replace with a1.5A 125V Littelfuse Pico II(or clip-in fuse holder). - 7805 Voltage Drop & White Vertical Line: Replacing the worn
7805(1A) with a78S05(2A) and soldering a470 µF 10Vor22 µF MLCCacross the 7805 output/GND pins eliminates the faint white vertical bar down the middle of the screen!
3 SMD Capacitor Recap Checklist
- Early
SHVC-CPU-01,SNS-CPU-GPM-01/02, andSNS-CPU-RGB-01boards use 8 to 11 surface-mount aluminium electrolytic capacitors that leak fishy electrolyte onto the video DAC and audio traces. - Critical Caps:
C57, C58(10 µF 16VBipolar or tantalum audio coupling),C59(100 µF 6.3VVideo coupling — causes dark/rolling picture when dry!), and the33 µF/47 µFrail caps. - SHVC-SOUND Module: On 1990–91 consoles with the removable metal audio box, three SMD caps (
10 µF&47 µF) inside the module leak and mute one or both stereo channels!
Architectural Summary & Motherboard Generations
From 1990 2-PPU + Separate Sony Sound Module boards to 1995 S-CPUN 1CHIP and SNS-101 Jr. revisions
S-WRAM) + 64 KB Video RAM (2×32KB SRAM) + 64 KB Audio RAM; 46+16-Pin Cartridge Slot (supports Super FX, SA-1, DSP-1, CX4 co-processors)
2-PPU Motherboards (SHVC-CPU-01, GPM-01/02, RGB-01, APU-01) 1990 – 1994 • Separate S-CPU, S-PPU1 & S-PPU2
All first- and second-generation SNES and Super Famicom motherboards use three separate surface-mount QFP custom chips for the main system: U1 S-CPU (5A22-01/02), U2 S-PPU1 (5C77-01), and U3 S-PPU2 (5C78-01/02/03). While they have slightly softer horizontal RGB pixel edges than later 1CHIP boards, they enjoy 100% software accuracy with every game (including Air Strike Patrol shadow raster effects).
- SHVC-CPU-01 (1990–91): Features the removable shielded metal Sony
SHVC-SOUNDdaughterboard. Note that earlyS-CPU 5A22-01chips have a known DMA controller silicon bug and higher failure rate than5A22-02! - SNS-CPU-GPM-01 / GPM-02 (1992–93): Integrates the Sony SPC700 and S-DSP directly onto the main PCB and upgrades to
S-CPU A (5A22-02). - SNS-CPU-RGB-01 & APU-01 (1994): Combines the Sony SPC700 and S-DSP into a single
S-APUQFP chip and replaces the BA6592F video encoder with theS-RGB(BA6595F) encoder.
Super CIC & 50Hz / 60Hz PAL Switchless Mod
- PAL SNES 50Hz Lockout: On a PAL SNES (
SNSP-CPU-01 / 02), lifting Pin 24 of S-PPU1 and Pin 30 of S-PPU2 from their grounded PCB pads and toggling them between GND (60Hz NTSC) and +5V (50Hz PAL) switches the video refresh rate! - Lockout Chip (F411 / F413 CIC): Lifting Pin 4 of the 18-pin
F411/F413CIC chip disables the regional lockout on older games, while installing an open-source SuperCIC PIC16F630 unlocks 100% of SA-1 and S-DD1 titles (Super Mario RPG, Kirby Super Star, Star Ocean).
SNS-CPU-1CHIP-01 / 02 / 03 1995 – 1996 • Combined S-CPUN 160-Pin QFP
In 1995, Nintendo combined the S-CPU, S-PPU1, and S-PPU2 into a single 160-pin QFP ASIC labeled S-CPUN on the SNS-CPU-1CHIP-01, 1CHIP-02, and 1CHIP-03 motherboards (typically serial numbers starting with UN309+ in North America or late Super Famicoms). Because the digital-to-analog video conversion now happens inside a single modern ASIC without inter-chip bus capacitance, 1CHIP boards output dramatically sharper, razor-crisp RGB pixels.
1CHIP Brightness Attenuation & 1CHIP-03 CSYNC Restoration
- Over-Bright RGB White Levels on 1CHIP: Factory 1CHIP boards drive their RGB lines roughly 15% too bright (~0.85 Vpp instead of 0.70 Vpp), clipping white highlights on OSSC/RetroTINK. Soldering three
750 Ω1% resistors from the R, G, and B outputs of the S-RGB encoder to Ground (or replacing shunt resistorR3of the S-CPUN DAC reference from1.6 kΩto1.82 kΩ) restores exact SMPTE 0.7 Vpp levels! - 1CHIP-03 Missing CSYNC on Multi-Out Pin 3: On the final
SNS-CPU-1CHIP-03revision, Nintendo omitted the resistor/transistor network connecting CSYNC to Multi-Out Pin 3! Bridge jumper padR9(or install a470 Ωresistor) to restore CSYNC on Pin 3.
SNES Jr. (SNS-101) & Super Famicom Jr. (SHVC-101) 1997 • SNN-CPU-01 1CHIP Core
Released in late 1997 in a compact redesigned shell (`SNS-101` / `SHVC-101`), the SNES Jr. contains the exact same desirable S-CPUN 1CHIP ASIC on its SNN-CPU-01 motherboard! However, to cut costs, Nintendo disconnected RGB (Pins 1, 2, 4), CSYNC (Pin 3), and S-Video Luma/Chroma (Pins 7, 8) from the rear Multi-Out port, leaving only Composite Video and Stereo Audio enabled out of the box.
Restoring RGB & S-Video on the SNES Jr. (THS7374 / S-RGB Bypass)
- Because the
S-CPUNchip still outputs raw Analog R, G, B, and CSYNC on its pins (and the board even has an onboardS-RGB Achip with S-Video pins present!), installing a smallTHS73744-channel RGB bypass amp PCB wired to Multi-Out Pins 1, 2, 3, 4 turns the SNES Jr. into the cleanest RGB output SNES ever made!
Diagnostic Flowcharts & S-CPU / S-PPU1 / S-PPU2 Fault Matrix
Isolating power/reset failures vs. the infamous early-1990s SHVC custom silicon degradation ("Chip Rot")
1. Completely Dead — Red Power LED Does Not Light
Diagnostic Decision Tree
- Test Fuse F1 (1.5A Pico II): Measure continuity across the green axial fuse
F1next to the 7805 regulator. If open, check that the 7805 output pin isn't shorted to GND, then replaceF1with a 1.5A 125V Pico fuse. - Inspect US SNS-001 Rear DC Jack: On North American consoles, the plastic cylinder inside the rear power socket breaks off, causing the two metal contacts to lose tension or touch. Replace the rear power jack block.
- Verify 7805 Regulator Input/Output: Confirm +9V to +13V DC on 7805 Pin 1 (Input) and +4.95V to +5.05V DC on Pin 3 (Output) when the power switch is ON.
2. Black Screen on All Cartridges (Red Power LED Lights Up)
Diagnostic Decision Tree
- Clean & Inspect the 62-Pin Cartridge Connector: Unlike the NES, early SHVC-CPU-01 boards have a removable press-fit 62-pin cartridge slot block! Unplug it, clean both upper and lower connectors with DeoxIT D5, and inspect for bent pins.
- Check 21.47727 MHz Master Clock &
/RESET(U10 Reset IC): Verify a clean 21.47 MHz clock entering S-CPU Pin 90 and confirm/RESETrises to +5V after power-on. - SHVC-SOUND Module Seating (1990–91 Boards): On
SHVC-CPU-01boards, if the removable metal sound box is unplugged or its 24-pin header has cold solder joints, every SNES game will hang on a black screen waiting for the SPC700 audio handshake at$2140!
3. S-CPU vs. S-PPU1 vs. S-PPU2 vs. WRAM/VRAM Fault Isolation Matrix ("SNES Chip Rot")
When an early SHVC-CPU-01 or GPM-01 boots the official SNES Burn-In Test Cartridge ROM (on an FXPAK Pro / SD2SNES) or shows graphical/gameplay corruption, use this symptom table to identify which QFP IC has failed before desoldering:
| Suspect Chip | Classic Game / Visual / Functional Symptoms | Burn-In Test ROM Result & Bench Fix |
|---|---|---|
S-CPU (5A22-01)U1 • QFP-100 |
Games boot title screen and play music, then crash when starting gameplay; sprites vanish or warp across the screen (broken DMA/HDMA); character walks in one direction uncontrollably (broken internal auto-joypad read); math errors in Mode 7 / RPG damage calculation. | Fails DMA, HDMA, Multiply/Divide, or Joypad tests. Replace early S-CPU 5A22-01 with a donor S-CPU A (5A22-02) or S-CPU B using hot air + flux. |
S-PPU1 (5C77-01)U2 • QFP-100 |
Missing or scrambled sprite layers while background HUD text is legible; broken Mode 7 scaling/rotation (F-Zero, Super Mario Kart track is garbled blocks while sky/music work); vertical jailbar slices through tiles. | Fails OBJ (Sprite) or Mode 7 / BG rendering tests while VRAM chips test OK. Replace S-PPU1 (5C77-01) from donor board. |
S-PPU2 (5C78-01/03)U3 • QFP-100 |
Wrong palette colours, missing transparency/colour-math effects (ghosts in Super Mario World or water in Donkey Kong Country are solid black/opaque), or screen rolls/loses sync. | Fails Color Math / Window / Palette CGRAM tests. Inspect QFP pins for corrosion, or replace S-PPU2 (5C78). |
VRAM (U4 / U5)2× 32KB SRAM |
Consistent repeating vertical lines or corrupted characters across all backgrounds and sprites (U4 = Low Byte VRAM, U5 = High Byte VRAM). | Burn-In Test ROM flags VRAM LOW or VRAM HIGH FAIL. Replace the failed 28-pin SOP 32KB SRAM (LH52256 / TC55257). |
Dedicated SNES / Super Famicom Connector Pinouts
Bi-directional connector reference pages with interactive SVG diagrams and NTSC vs PAL RGB SCART schematics
1. Nintendo 12-Pin Multi-Out A/V Connector (NTSC vs PAL RGB SCART) →
Complete 12-pin Multi-Out diagram covering Analog RGB (Pins 1, 2, 4), S-Video Y/C (Pins 7, 8), Composite (Pin 9), Stereo Audio (Pins 11, 12), and the critical NTSC Pin 3 CSYNC vs. PAL Pin 3 +12V warning!
Open Multi-Out Pinout →2. SNES / Super Famicom 7-Pin Controller & Mouse Port →
7-pin single-row keyed connector pinout, 16-bit dual-4021 shift register bit order (B, Y, Select, Start, D-Pad, A, X, L, R), SNES Mouse ID bits, and official Nintendo wire colour warning.
SNES Custom Silicon, Audio & Memory Reference
Core processors and standard SRAM/logic chips shared with our IC Pinout Finder
Ricoh 5A22 (WDC 65C816 Core)
16-bit WDC 65C816 microprocessor core with 24-bit address bus (16MB memory space), 8-channel DMA/HDMA controller, hardware multiply/divide, and joypad serial interface.
Inspect 65C02/65C816 Family → SOP-28 • Cart Save SRAM6264 (8KB) & 62256 (32KB) SRAM
Used on SNES LoROM/HiROM cartridges for CR2032 battery-backed game saves, and as the 2×32KB Video RAM (U4/U5) on 2-PPU motherboards.
Open 6264 SRAM Pinout → SOP-16 • Cart MAD-1 / Decoder74LS139 Dual 2-to-4 Decoder
Used on early SNES LoROM/HiROM cartridges (before the Nintendo MAD-1 chip) to decode ROM chip enables and protect battery-backed SRAM during power-down.
Open 74LS139 Pinout → SOP-16 • Multi-ROM Decoder74LS138 3-to-8 Line Decoder
Used on multi-chip SNES cartridges and development EPROM boards to split bank selects across multiple 27C801 / 29F032 flash ROMs.
Open 74LS138 Pinout →