Nintendo
Interactive Flowchart Nintendo NES & Famicom
NES-CPU-07 / NES-CPU-11 & Mitsumi Power/RF Module — Front-Loader NES-001, Top-Loader NES-101 & HVC-001 Famicom
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
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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
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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
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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.
Summary
The #1 capacitor failure in the Front-Loader NES-001 is the large 2200 uF 25V radial reservoir capacitor inside the shielded Mitsumi RF/Power/AV module. When it dries out, heavy 60Hz/50Hz wavy hum bars roll vertically up the composite video output.
Interactive Bench Oscilloscope — Verify Pre- & Post-Recap Waveforms
Open Full Signal Visualizer →Click any test point below to compare a healthy recapped rail or clock against high-ESR electrolytic capacitor ripple and droop:
Safety & Warnings
NES-001 takes 9V AC (or DC), whereas Japanese Famicom (HVC-001) is STRICTLY 10V DC Centre-Negative!
Never plug the original NES-002 9V AC transformer brick into a Japanese Famicom (HVC-001), which lacks a bridge rectifier and will blow its 7805 regulator immediately!
Is This Your Board?
- Front-Loader NES-001 mainboards (NES-CPU-04 to NES-CPU-11) carry only a few small axial/radial caps on the logic PCB; the main power/AV capacitors sit inside the soldered metal RF box on the rear corner.
Verified
Check
Verified rows are agreed by two or more independent sources. Check rows are revision-dependent or single-sourced — confirm the value against your own board before ordering.
NES-001 Mitsumi Power / AV / RF Module
| Ref | Value | Voltage | Type | Function | Notes | Confidence |
|---|---|---|---|---|---|---|
C1 (Main) |
2200 uF | 25 V | Radial (105 C Low-ESR) | Bridge rectifier primary DC reservoir | Primary culprit for wavy hum bars on composite video. | Verified |
C2 |
100 uF | 16 V | Radial | 7805 +5V output filter | Verified | |
C3 |
10 uF | 25 V | Radial | Composite video amplifier coupling | Verified | |
C4 |
1 uF | 50 V | Radial | Mono audio RCA output coupling | Verified | |
C5 |
47 uF | 16 V | Radial | Video buffer rail decoupling | Verified |
NES-001 Mitsumi Power / AV / RF Module — shopping list
- 1 x 2200 uF 25 V Radial (105 C Low-ESR)
- 1 x 100 uF 16 V Radial
- 1 x 10 uF 25 V Radial
- 1 x 1 uF 50 V Radial
- 1 x 47 uF 16 V Radial
NES-CPU-07 / NES-CPU-11 Mainboard
| Ref | Value | Voltage | Type | Function | Notes | Confidence |
|---|---|---|---|---|---|---|
C1 |
100 uF | 10 V | Radial / Axial | +5V logic rail decoupling | Verified | |
C8 |
10 uF | 25 V | Radial | 10NES CIC / Reset timing | Verified | |
C14 |
1 uF | 50 V | Radial | 2A03 APU audio channel coupling | Verified | |
C24 |
2.2 uF | 50 V | Radial | PPU video DAC filter | Verified |
NES-CPU-07 / NES-CPU-11 Mainboard — shopping list
- 1 x 100 uF 10 V Radial / Axial
- 1 x 10 uF 25 V Radial
- 1 x 1 uF 50 V Radial
- 1 x 2.2 uF 50 V Radial
Whole-Machine Shopping List
- 1 x 2200 uF 25 V Radial (105 C Low-ESR)
- 1 x 100 uF 16 V Radial
- 2 x 10 uF 25 V Radial
- 2 x 1 uF 50 V Radial
- 1 x 47 uF 16 V Radial
- 1 x 100 uF 10 V Radial / Axial
- 1 x 2.2 uF 50 V Radial
Recap Tips
- Boil and clean the 72-pin cartridge ZIF connector while the NES-001 mainboard is out of the shell.
Related Symptoms
- Blinking red power LED (1 Hz reset loop) Dirty 72-pin cartridge connector failing 10NES CIC authentication.
Sources & References
- Console5 TechWiki - Nintendo NES-001 Mainboard and Mitsumi RF module capacitor tables.