Nintendo Famicom Troubleshooting Guide
Fault-finding for the Nintendo Family Computer (Famicom, HVC-001). Nintendo's service figures for the machine are in the HVC section of its 1992 service manual.[1] The Famicom Disk System, the AV Famicom (HVC-101) and clones are not covered here. The NES has a different board, and its designators do not transfer.
Cartridge and connector first
[edit | edit source]Nintendo's system diagram gives the same symptoms for a faulty 60-pin card connector as for a faulty CPU board: no picture, a game that stops part-way, or a broken-up picture. It adds that a dirty cassette edge produces the same symptoms, so try another cassette first.[1] Clean the cassette contacts and the console connector and retest before probing the board. The card connector is listed in Nintendo's repair price list as a replaceable part.[1]
Nintendo of America's care leaflet tells owners not to touch or blow on a cartridge edge connector.[2]
Not a fault
[edit | edit source]Nintendo's table of things that are not faults (p. 3) covers the TV connection:[1]
| Symptom | Check |
|---|---|
| No game picture, only noise; screen bright | TV tuned to the console's channel (1 or 2); adapter connected; console switched on; TV/GAME switch at GAME; RF plug in the RF switch; cassette fully inserted; cables at the RF switch behind the TV not pulled off |
| Game shows but TV broadcasts do not, or are poor | TV/GAME switch at TV; aerial cable properly connected to the RF switch; if a splitter is used, the RF switch must not be connected ahead of it |
| Both game and broadcasts poor | If a 75/300 Ω converter is used, swap its two flat-lead terminals at the TV, or connect without the converter |
| Striped pattern during a game | The console's channel should be one with no broadcast; with the console off, that channel should show no picture or sound. Check the VHF fine tuning |
| No colour, weak or wrong colour | VHF fine tuning; the TV's colour controls |
| Picture shakes or rolls | The TV's vertical and horizontal hold |
| Corners of the picture distorted | Brightness too high; horizontal hold |
Power
[edit | edit source]| Where | Expected | If wrong |
|---|---|---|
| HVC-002 adapter, no load | DC 13.5 ± 1.5 V | Outside 12–15 V: suspect the adapter |
| Adapter plug | Centre negative | Use only a centre-negative 10 V DC adapter |
| 7805 input | 13–14 V | Adapter, DC jack and its solder joints, or the fuse on a VCCI board |
| 7805 output | 5 V | Regulator, or a short on the 5 V rail |
| RF switch terminal, game mode | DC 5 V | Nintendo blames the power IC in the RF modulator or the PC joiner wire |
Sources: adapter, 7805 and RF switch figures from Nintendo's manual (pp. 2 and 6);[1] the adapter's rating and polarity from Famicom World, which gives the HVC-002 as 10 V DC 850 mA, centre negative, and warns against using an NES adapter, whose output is AC.[3]
The board has one regulated rail, 5 V from the 7805.[1][4]
No power
[edit | edit source]- Measure the adapter off load: 12–15 V DC, centre negative.
- With the console running, move the plug. If the picture cuts out, the DC jack's solder has cracked from the cord being pulled sideways. Nintendo marks three points round the jack to reinforce with solder.[1]
- On a VCCI board, check the fuse. Nintendo lists the fuse as a VCCI part, and its VCCI power circuit adds a choke and a fuse that the standard HVC circuit does not have.[1]
- Check the power switch for continuity.
- Check the 7805: 13–14 V in, 5 V out.
Symptoms
[edit | edit source]| Symptom | Work through, in order |
|---|---|
| No picture, no sound, no power | Adapter off-load reading; DC jack joints; fuse on a VCCI board; power switch; 7805 input and output |
| Noise only, screen bright | The first row of the not-a-fault table above[1] |
| Black screen, game freezes or broken-up picture | Another cassette; clean the cassette edge and the 60-pin connector; then the card connector itself; then the CPU board[1] |
| Picture but no sound | TV volume and channel; the sound is generated in the CPU (RP2A03, U6), so there is no separate sound chip[5][4] |
| Controller I dead, erratic or pausing on its own | Nintendo's controller fault list (p. 4): worn A and B buttons and wires broken inside the cord. Most controller faults are on controller I. The controllers plug into connectors on the board and are replaced as assemblies[1] |
| Controller II buttons dead | Replace controller II only when its own buttons fail. It has a microphone and no SELECT or START buttons[1] |
| Cassette works only when pressed or wiggled | Cassette contacts and the card connector |
See Nintendo Famicom General Maintenance for the controller fault list in full and the cleaning procedure.
Chips
[edit | edit source]Console5 maps the HVC-CPU-07 board as follows:[4]
| Position | Part | Type |
|---|---|---|
| U6 | RP2A03E | CPU, with the sound generator |
| U5 | RP2C02E-0 | PPU |
| U1, U4 | MB8416A-15L | 2K × 8 static RAM |
| U2 | 74LS373 | Octal latch |
| U3 | 74LS139P | Dual 2-to-4 decoder |
| U7, U8 | 40H368P | Hex inverting buffer |
| – | 7805 | +5 V regulator |
The HVC-CPU-GPM-02 board has the same positions with XRM6216-10 RAMs, an RP2C02G-0 PPU and an RP2A03E-0 CPU.[4] The controllers' shift registers are inside the controllers: Nintendo's price list has the 4021 and 4069 as controller parts.[1]
The Famicom has no CIC lockout chip, so the NES-001's blinking-power-light fault cannot occur.[6]
Probing safely
[edit | edit source]Nintendo's handling notes (p. 1):[1]
- Do not check continuity on a meter's high-resistance range. It applies 4.5 to 22.5 V and can destroy the device.
- Earth yourself through a resistance of several MΩ, and avoid synthetic clothing.
- Use an earthed soldering iron that does not leak. The chips' protection diodes cope with a small leak, but a large one destroys them. Nintendo specifies a leak-free or IC-rated iron of about 30 W for the console (p. 7).
- Switch off before removing or fitting any IC.
Related pages
[edit | edit source]- Nintendo Entertainment System
- Nintendo Famicom General Maintenance
- Nintendo Famicom Capacitor Replacement Guide
- Nintendo Famicom Service Manual
- Nintendo Entertainment System Troubleshooting Guide
- Recommended Tools
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 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), dated 7 August 1992, hosted at Nintendo Famicom Service Manual. HVC section: p. 1, IC handling; p. 2, system diagram with faults by unit, adapter DC 10 V, DC 13.5 ± 1.5 V off load; p. 3, not-a-fault table; p. 4, controller faults and replacement; p. 6, DC jack solder points, RF switch terminal DC 5 V in game mode, HVC and HVC (VCCI) power circuits (7805, 13–14 V in, 5 V out); pp. 7–9, exploded views and tools; p. 10, repair price list.
- ↑ Nintendo of America, Product Maintenance, Troubleshooting and Service Guide (World Class Service leaflet), hosted at Nintendo World Class Service NES Product Maintenance Troubleshooting And Service Guide. Maintenance tip 4.
- ↑ Famicom World, "Famicom Power Adaptor" (retrieved 2026-10-01).
- ↑ 4.0 4.1 4.2 4.3 Console5 TechWiki, "Famicom" (retrieved 2026-10-01). Chip maps for HVC-CPU-07 and HVC-CPU-GPM-02.
- ↑ NESdev Wiki, "CPU pinout" (retrieved 2026-10-01): audio outputs on RP2A03 pins 1 and 2.
- ↑ NESdev Wiki, "CIC lockout chip" (retrieved 2026-10-01): "The Famicom and toploading NES consoles do not contain this chip."