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Rebuild: supply is 10V DC 850mA (HVC-002) not 9V, and the barrel polarity was stated backwards; no 3.3V or 12V rail exists (fullsnes); regulator is U12/U9 not IC601; cap table (C59-C60 220uF audio, C67 470uF, C72, C81) fabricated and contradicted the cap guide; controller port is a proprietary 7-pin not mini-DIN. Added Nintendo Control Deck diagnostic table and Multi Out pinout. F1 1.5A confirmed. Cited; Unverified data cleared
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[[File:Nintendo-Super-NES-Mk1-Motherboard-Top.jpg|thumb|293x293px|Nintendo 16-bit mainboard of the SHVC/SNS generation]]
The '''Super Famicom''' is a robust machine that ages in three predictable ways: the plastics discolour, the cartridge connector gets dirty, and the surface-mount electrolytics slowly go. This guide covers cleaning, power checks, connector care and the board-level diagnostics Nintendo published for its own service centres.


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== Power supply ==
[[File:Nintendo-Super-NES-Mk1-Motherboard-Top.jpg|thumb|293x293px|Super Famicom (HVC-CPU-01) Motherboard]]
ย 
Proper maintenance is essential to preserve the reliability and longevity of your '''Super Famicom''' (SFC, Japanese Super Nintendo). Now over thirty years old, these consoles face age-related risks such as capacitor failure, power supply drift, and brittle plastics. This guide details best-practice cleaning, preventive care, and periodic checks for all SFC mainboard revisions.
'''The Super Famicom takes 10&nbsp;V DC, centre negative.''' The Japanese adapter is the '''HVC-002''', shared with the Family Computer: input AC 100&nbsp;V 50/60&nbsp;Hz 18&nbsp;VA, output DC 10&nbsp;V 850&nbsp;mA, with the outer sleeve positive and the centre pin negative.<ref name="hvc002">Famicom World, "Famicom Power Adaptor" โ€” https://famicomworld.com/workshop/tech/famicom-power-adaptor/ . HVC-002 rating plate: AC 100&nbsp;V 50/60&nbsp;Hz 18&nbsp;VA in, DC 10&nbsp;V 850&nbsp;mA out, centre negative. Regional variants HVC-002 (HKG), AC 200&nbsp;V 50&nbsp;Hz 17&nbsp;W, and HVC-002 (TPE), AC 110&nbsp;V 60&nbsp;Hz 18&nbsp;VA, carry the same DC output.</ref> The North American SNES takes the same 10&nbsp;V DC from its SNS-002.<ref name="fullsnes">Martin Korth, ''fullsnes'' โ€” SNES hardware specifications โ€” https://problemkaputt.de/fullsnes.htm . Sections "SNES Power Supply" and "SNES Audio/Video Connector Pinouts". Source for the 10&nbsp;V DC 850&nbsp;mA NTSC/Japanese supply, the 9&nbsp;V AC PAL supply, the input diode drop, the 7805 producing the single +5&nbsp;V logic rail, the audio amplifier running from the unregulated rail, and the 12-pin Multi Out pinout.</ref>
ย 
{| class="wikitable styled-table" style="width:80%;"
|+'''DC input jack'''
! Contact !! Function
|-
| Outer sleeve || +10 V DC
|-
| Centre pin || 0 V / ground
|}
ย 
Check the polarity before you trust any replacement supply. Centre-negative barrel jacks are unusual, and a centre-positive supply of the right voltage will be connected backwards.
ย 
'''Never fit a PAL SNES supply to a Super Famicom.''' The European SNSP machine takes 9&nbsp;V ''AC'' and rectifies it internally; the Super Famicom expects DC that has already been rectified.<ref name="fullsnes" /> The same warning applies in reverse to NES adapters, which are also AC.
ย 
=== What the console does with it ===
ย 
Inside, the 10&nbsp;V passes through a series diode โ€” so the internal rail sits nearer 9&nbsp;V โ€” and then splits two ways:<ref name="fullsnes" />


== Regular Cleaning ==
* A '''7805''' regulator produces the single '''+5&nbsp;V''' logic rail. The CPU, PPUs and APU run from this and nothing else. It is '''U12''' on SHVC-CPU-01, SNS-CPU-GPM, SNS-CPU-RGB and SNS-CPU-APU boards, and '''U9''' on the 1CHIP and SNN boards.<ref name="c5snes">Console5 TechWiki, ''SNES'' โ€” https://wiki.console5.com/wiki/SNES . Secondary source: a community wiki compiled from physical boards. Used for the per-revision chip maps, the position of the 7805 regulator, capacitor lists, and its transcription of Nintendo's Control Deck diagnostic table.</ref>
* The '''unregulated ~9&nbsp;V''' feeds the audio amplifier only. The console will run with that rail missing โ€” you simply get no sound.<ref name="fullsnes" />


=== External Case & Controller Ports ===
'''There is no 3.3&nbsp;V rail and no 12&nbsp;V rail in a Super Famicom.''' If you are looking for one, you are looking for something that is not there.
* Wipe the ABS plastic shell with a '''damp microfibre cloth and mild detergent'''. Avoid abrasive cleaners.
* For yellowed plastics, '''retrobrite''' is possible but monitor temperature and exposure to prevent warping.
* Clean controller ports with a soft brush and isopropyl alcohol (IPA, >90%). Remove stubborn debris with a wooden toothpick.


=== Cartridge Slot & Expansion Port ===
=== The fuse ===
* Use compressed air to blow out dust from the cartridge and bottom expansion slots.
* For poor cartridge contact, gently insert and remove a clean, dry cartridge several times.
* If contacts remain unreliable, use a '''contact cleaning card''' or a thin strip of card dampened with IPA.


=== Internal PCB Cleaning ===
Nintendo's diagnostic table lists a defective '''F1, a 1.5&nbsp;A fuse''' as the first probable cause of a dead console, ahead of the regulator.<ref name="nintendodiag">Nintendo service literature, Control Deck diagnostic table, transcribed by Console5 from ''Manual Tรฉcnico do Super NES'' Rev. 01-94 (pt-BR), which covers the SHVC and GPM boards, controllers, Super Scope 6 and mouse. Reproduced at https://wiki.console5.com/wiki/SNES . Source for the malfunction/probable-cause table, the F1 1.5&nbsp;A fuse rating, the TC1 master-clock alignment figures, and the instruction not to clean the 62-pin connector.</ref> Check it before anything else, and replace like for like.
* Unplug the console and allow capacitors to discharge for several minutes.
* Remove the top shell (Gamebit 4.5 mm driver required).
* Gently brush dust from the PCB with an anti-static brush.
* Remove corrosion with IPA and a soft toothbrush; for stubborn areas, use a fibreglass pen with care.
* Avoid excessive moisture around the cartridge slot and S-ENC/S-PPU chips.


=== Controller Cleaning ===
== Nintendo's diagnostic table ==
* Open controllers with a Phillips screwdriver.
* Wash button caps and D-pad in warm soapy water; dry thoroughly.
* Clean PCB contacts with IPA and a cotton bud.
* Replace conductive pads if buttons are unresponsive.


== Power Supply & Voltage Checks ==
Transcribed from Nintendo's own service literature. The probable causes are in Nintendo's order of priority, which is itself useful information โ€” Nintendo put the cartridge connector at the top of three separate faults.<ref name="nintendodiag" />


The Super Famicom uses an external AC adapter (HVC-002) supplying '''9V DC, centre negative'''. Ageing adapters may drift out of spec, risking console damage.
Nintendo prefaces it: before attempting any repair, strip the unit and inspect the PCB thoroughly for damaged or missing components and traces, solder defects, dirt and corrosion.


{| class="wikitable styled-table" style="width:70%;"
{| class="wikitable styled-table" style="width:100%;"
! Pin (Barrel) !! Function !! Healthy Range
|+'''Control deck โ€” malfunctions and probable causes'''
! Malfunction !! Probable causes, in order
|-
|-
| Outer || GND || 0 V
| Solid colour screen (a black screen counts here) || 62-pin connector; sound module; poor solder; U1 (CPU); U3 (PPU2); U6 (WRAM); U2 (PPU1); U7 (RGB encoder); X1 (21 MHz oscillator); U8 (CIC)
|-
|-
| Inner || +9 V DC (centre negative) || 8.5 โ€“ 10.5 V (unloaded)
| Scrambled video images || 62-pin connector; poor solder; U3 (PPU2); U1 (CPU); U2 (PPU1); U4 or U5 (256K SRAM)
|-
| Distorted or no sound || Sound module; connector P5; U1 (CPU); U10 (amplifier); Q18
|-
| No reset (the system reset line, not the button) || U8 (CIC); X2 (4 MHz oscillator); U9 (74HCU04)
|-
| Poor or no colour || TC1 โ€” master clock frequency must be adjusted to 21.47727 MHz (NTSC) or 17.734475 MHz (PAL); U3 (PPU2); U7 (RGB encoder); X1 (21 MHz oscillator)
|-
| No power || F1 (1.5 A fuse); D1; T1 (line filter); U12 (7805 regulator); VA1 (surge absorber); Q18; P3 (power switch)
|-
| Snowy screen || RF modulator
|-
| Intermittent or no controller operation || Front unit PCB assembly; FFC harness (flat cable); connector P2; U1 (CPU)
|-
| Frozen screen or erratic program operation || 62-pin connector; poor solder; U1 (CPU); U3 (PPU2); U2 (PPU1)
|-
| Ejector will not eject game paks || Early-version ejector โ€” Nintendo's instruction was to replace on customer complaint only
|}
|}


''Always measure adapter output with a multimeter before use.''
Nintendo notes that a few of the power-section parts were eliminated over the machine's production life, so not every board has a D1, T1, VA1 or Q18.<ref name="nintendodiag" />


=== Internal Voltage Regulation ===
'''TC1 is a trimmer, and it is adjustable.''' If a console has poor or no colour and everything else checks out, Nintendo's own remedy is to set the master clock to 21.47727&nbsp;MHz on an NTSC or Japanese machine, or 17.734475&nbsp;MHz on a PAL one, at TC1. Korth's hardware reference gives the same PAL crystal figure independently.<ref name="nintendodiag" /><ref name="fullsnes" />
* The SFC mainboard regulates +9V DC down to +5V for logic and +3.3V/+12V for AV circuitry.
* Measure +5V at the voltage regulator output (usually IC601, 7805 or equivalent): should read '''4.90 โ€“ 5.15 V''' under load.
* If voltage is low or fluctuating, suspect a failing regulator or dried-out capacitors.


=== Safe Power Supply Replacements ===
== The cartridge connector ==
* Use only regulated adapters rated '''9V DC, โ‰ฅ1.3A, centre negative'''.
* Modern replacements: Triad WAU090-1300, Retro Game Restore PSU, or equivalent with over-voltage protection.


== Connector & Socket Corrosion ==
The cartridge slot is a 62-pin edge connector and it is the first thing Nintendo blames for three of the ten faults above.<ref name="nintendodiag" /><ref name="fullsnes" />


Age and humidity can cause oxidation on connectors, leading to intermittent faults.
Nintendo's own instruction was blunt: '''"Do not attempt to clean 62 pin connectors; they should be replaced."'''<ref name="nintendodiag" /> That was written for warranty service centres with a parts bin, and it is worth reading as a statement of how much Nintendo trusted cleaning rather than as advice for a modern restorer with no source of new connectors. In practice, cleaning is what people do and it usually works โ€” but if a console keeps coming back after cleaning, Nintendo's view was that the connector itself was the problem.


=== Areas to Inspect ===
In contrast to the NES-001, the Super Famicom connector is a conventional edge connector, so inserting and removing a cartridge does wipe the contacts. That is why the Super Famicom does not have the NES's reputation for needing constant attention.
* '''Cartridge slot''' (top-loading 62-pin)
* '''Controller ports''' (7-pin mini-DIN)
* '''AV Multi-Out''' (12-pin)
* '''DC input barrel jack'''
* '''Expansion port''' (bottom, rarely used)


=== Cleaning Procedure ===
* Clean the '''cartridge''' contacts as well as the slot. A cartridge with tarnished contacts will dirty a clean console.
* Apply '''DeoxIT D5''' or IPA to a lint-free swab; gently clean contacts.
* Isopropyl alcohol on a lint-free swab or a contact-cleaning card. Never metal polish and never an abrasive on gold plating.
* For stubborn corrosion, use a fibreglass pen or pink pencil eraser with caution.
* Inspect for bent pins and for cracked solder joints where the connector meets the mainboard.
* Reseat connectors (e.g. AV, controller) several times to wipe contacts.


== Capacitor Health & Replacement ==
== Connectors and ports ==


While SFC boards use high-quality Japanese capacitors, all electrolytics degrade with ageโ€”especially in humid climates.
{| class="wikitable styled-table" style="width:85%;"
ย 
|+'''External connectors'''
=== Typical Capacitor Failures ===
! Connector !! Detail
* '''Audio loss, buzzing, or distortion'''
* '''Video instability, colour shift, or rolling image'''
* '''No power or random resets'''
* '''Voltage regulator instability'''
ย 
=== Capacitor List (Mainboard HVC-CPU-01 Example) ===
{| class="wikitable styled-table" style="width:80%; text-align:center;"
! Location !! Value !! Function !! Notes
|-
|-
| C59, C60 || 220 ยตF / 10 V || Audio output || Replace with low-ESR
| Cartridge slot || 62-pin edge connector
|-
|-
| C61, C62 || 100 ยตF / 16 V || Video circuit || Use 105ยฐC rated
| Controller ports (ร—2) || Proprietary 7-pin connector โ€” not a mini-DIN, despite the resemblance
|-
|-
| C67 || 470 ยตF / 16 V || Main +5V filter || Critical for power stability
| AV Multi Out || 12-pin Nintendo Multi Out
|-
|-
| C72 || 10 ยตF / 16 V || Reset circuit || Small, but important
| DC input || Barrel jack, outer sleeve positive
|-
|-
| C81 || 1000 ยตF / 10 V || Power input smoothing || May bulge or leak
| Expansion port (underside) || Rarely used; keep the original cover fitted
|}
|}


''See [[Super Famicom Capacitor Replacement Guide]] for a full list by revision.''
=== Multi Out pinout ===


=== Replacement Guidance ===
Useful when chasing a video fault or building a cable.<ref name="fullsnes" />
* Use '''Japanese 105ยฐC low-ESR capacitors''' (e.g. Nichicon, Panasonic, Rubycon).
* Observe polarityโ€”electrolytics are polarised.
* Clean any leaked electrolyte with IPA and neutralise corrosion with vinegar if needed.


== Common Failure Points ==
{| class="wikitable styled-table" style="width:80%;"
ย 
|+'''AV Multi Out'''
{| class="wikitable styled-table" style="width:100%; text-align:center;"
! Pin !! Signal !! Pin !! Signal
|+'''Super Famicom Typical Faults'''
! Symptom !! Likely Cause !! Quick Test / Hint
|-
|-
| No power / dead || Blown fuse (F1), failed 7805 regulator, bad power jack || Check fuse continuity; measure +5V at regulator
| 1 || RGB red || 7 || S-Video Y (luminance)
|-
|-
| No video / black screen || Dirty cartridge slot, failed PPU, bad AV cable || Clean slot; try known-good game; test AV cable
| 2 || RGB green || 8 || S-Video C (chroma)
|-
|-
| Garbled graphics / sprites || Faulty VRAM, PPU1/PPU2 || Swap with donor chips (advanced)
| 3 || Composite sync (H/V) || 9 || Composite video
|-
|-
| No sound || Failed audio caps, S-SMP chip, mute transistor || Listen for faint hum; check C59/C60
| 4 || RGB blue || 10 || +5 V DC
|-
|-
| Random resets || Bad capacitors, cracked solder joints, failing regulator || Inspect C67, C81; reflow regulator pins
| 5 || Ground (video) || 11 || Audio left
|-
|-
| Controller not detected || Dirty port, failed S-IC, broken traces || Test with known-good controller; inspect port solder
| 6 || Ground (audio) || 12 || Audio right
|}
|}


== Device-Specific Subsystems ==
Red, green and blue carry a 1&nbsp;V DC offset with 1&nbsp;V peak-to-peak of video into 75&nbsp;ฮฉ; sync, luminance, chroma and composite are 1&nbsp;V peak-to-peak into 75&nbsp;ฮฉ; the audio pins are 5&nbsp;V peak-to-peak. On cost-reduced models pins 1โ€“4 and 7โ€“8 are reported as not connected, though they can be restored with modifications on the mainboard.<ref name="fullsnes" />
ย 
=== Cleaning connectors ===
ย 
* Contact cleaner or isopropyl alcohol on a lint-free swab; let it dry before powering up.
* A fibreglass pen or a soft eraser on stubborn corrosion on edge contacts โ€” with care, and never on gold you want to keep.
* Reseat the Multi Out and controller plugs a few times to wipe the contacts.
* Reflow the solder on the controller ports and the Multi Out if faults are intermittent. Nintendo lists "poor solder" as a probable cause of four separate symptoms.<ref name="nintendodiag" />
ย 
== Yellowed plastic ==
ย 
The Super Famicom's upper shell is the machine's most recognisable ageing problem. The grey ABS discolours unevenly, commonly with the top shell affected far more than the base and often in patches rather than uniformly.
ย 
Treatment is possible; see [[Retrobrite]] for the chemistry, the procedure and its risks. Two things worth knowing before you start:
ย 
* The discolouration is in the body of the plastic, not on the surface, so cleaning will not touch it.
* Over-treated ABS becomes brittle and the finish goes chalky. Watch the temperature and the exposure time, and stop early rather than late.
ย 
The coloured buttons, the cartridge slot dust flap and the base are usually less affected than the top shell, so treating the whole case uniformly can leave you with a mismatch you did not have before.
ย 
== Capacitors ==
ย 
Most of the electrolytics in a Super Famicom are '''surface-mount''' parts, which is what makes this machine worth checking rather than ignoring: an SMD capacitor that has begun to leak hides the evidence underneath its own body, and the corrosion is only visible once the can is off.<ref name="retrorgb">Bob, "Restoring A Super Nintendo", RetroRGB, 31 May 2020 โ€” https://www.retrorgb.com/restoring-a-super-nintendo.html . Used for the assessment that the SNES is not known for leaky capacitors, and that SMD leakage is concealed under the capacitor body.</ref>
ย 
That said, the Super Famicom is '''not''' in the class of machines where recapping is mandatory. Open it, look, and act on what you find.
ย 
The original SHVC-CPU-01 board carries thirteen electrolytics: two 47&nbsp;ยตF radials on the SHVC-SOUND module, ten surface-mount parts on the mainboard, and a 1000&nbsp;ยตF 25&nbsp;V radial reservoir on the DC input. Later revisions differ substantially โ€” see [[Super Famicom Capacitor Replacement Guide]] for the full per-revision lists and for the PAL C59 bipolar issue.<ref name="c5snes" />
ย 
Symptoms that justify pulling the board:
ย 
* Buzzing, distorted or missing audio
* Unstable video, rolling or colour shift
* Random resets or failure to power on
* Any visible brown, yellow or white residue around a capacitor, or green discolouration on the pads
ย 
== Cleaning ==


=== AV Multi-Out Port ===
=== Case and controllers ===
* Provides composite, S-Video, and RGB (with correct cable).
* Damp microfibre cloth and mild detergent on the shell. No abrasives.
* Pins can oxidiseโ€”clean with IPA and inspect for bent pins.
* Controller ports: soft brush and isopropyl alcohol; a wooden cocktail stick for anything lodged.
* If image is noisy, check C61/C62 and AV port solder joints.
* Open controllers with a Phillips driver, wash the button caps and D-pad in warm soapy water and dry them thoroughly, then clean the PCB contacts with isopropyl alcohol. Replace the conductive pads if buttons stay dead.


=== Expansion Port (Bottom) ===
=== Inside ===
* Rarely used, but can corrode if exposed to moisture.
* Unplug the console and let it sit before opening it.
* Clean with compressed air; cover with original plastic cap if possible.
* The shell screws are 4.5&nbsp;mm Gamebit security screws.
* Anti-static brush and compressed air on the board; isopropyl alcohol and a soft toothbrush on corrosion.
* Keep moisture away from the cartridge connector and the sound module.


=== Cartridge Slot ===
== Tools ==
* Most common source of "no boot" or "glitchy graphics".
* If cleaning fails, inspect for bent pins or cracked solder joints on the mainboard.


=== Internal Fuse (F1) ===
* 4.5&nbsp;mm Gamebit driver, Phillips drivers
* Glass or ceramic fuse near DC input; rated 1.5A.
* Digital multimeter
* Replace only with identical rating and type.
* Fine-tip temperature-controlled soldering iron, flux, desoldering braid or pump
* Hot air station if you are replacing surface-mount capacitors
* Isopropyl alcohol (99&nbsp;%), anti-static brush, lint-free swabs
* Contact cleaner
* Plastic spudger


== Recommended Tools & Consumables ==
See [[Recommended Tools]].


* '''ESD wrist-strap''' and anti-static mat
== Preventive maintenance ==
* '''Gamebit 4.5 mm driver''' (for case screws)
* '''Digital multimeter''' (voltage, continuity)
* '''Soldering iron''' (fine tip), leaded solder, flux
* '''Desoldering braid''' or pump (for capacitor work)
* '''Isopropyl alcohol''' (99% preferred)
* '''DeoxIT D5''' or similar contact cleaner
* '''Soft anti-static brush''' and microfibre cloth
* '''Fibreglass pen''' (for stubborn corrosion)
* '''Replacement capacitors''' (see above)
* '''Plastic spudger''' (for opening case, prying connectors)


== Preventive Maintenance Checklist ==
# Confirm the adapter is DC and centre negative before connecting it.
# '''Test power adapter''' output before every session.
# Clean the cartridge and the slot when games start needing a second insertion.
# '''Inspect and clean cartridge slot''' every 6โ€“12 months.
# Reseat the AV and controller plugs periodically.
# '''Check AV and controller ports''' for oxidation and reseat connectors.
# Open the case annually and look under the shield for capacitor residue.
# '''Open case annually''' to remove dust and inspect for capacitor leakage.
# Reflow the regulator, Multi Out and controller port joints if intermittents appear.
# '''Replace electrolytic capacitors''' if any show bulging, leakage, or if audio/video issues arise.
# Keep the console out of direct sunlight โ€” the plastics are the part most likely to be ruined by storage.
# '''Reflow solder joints''' on voltage regulator, AV port, and controller ports if dull or cracked.
# '''Store console in a dry, cool place'''โ€”avoid attic or basement humidity.
# '''Use original or high-quality replacement power supplies only.'''


== Quick-Fix Flowcharts ==
== Related pages ==
* [[Super Famicom]]
* [[Super Famicom Capacitor Replacement Guide]]
* [[Super Famicom Troubleshooting Guide]]
* [[Super Nintendo Entertainment System]]
* [[SNES Schematic]]
* [[Retrobrite]]
* [[Capacitor Failure Symptoms]]


=== No Power ===
== References ==
* Check AC adapter output โ†’ OK?
<references />
* Test fuse F1 for continuity.
* Measure +5V at regulator output.
* If no +5V, replace regulator and inspect capacitors.


=== No Video / Black Screen ===
* Clean cartridge slot and try known-good game.
* Test AV cable and port.
* Inspect for leaking capacitors near AV section.
* Swap PPU chips only as last resort (advanced).
[[Category:Nintendo]]
[[Category:Nintendo]]
[[Category:Maintenance Guides]]
[[Category:Maintenance Guides]]

Revision as of 19:50, 22 September 2026

Nintendo 16-bit mainboard of the SHVC/SNS generation

The Super Famicom is a robust machine that ages in three predictable ways: the plastics discolour, the cartridge connector gets dirty, and the surface-mount electrolytics slowly go. This guide covers cleaning, power checks, connector care and the board-level diagnostics Nintendo published for its own service centres.

Power supply

The Super Famicom takes 10 V DC, centre negative. The Japanese adapter is the HVC-002, shared with the Family Computer: input AC 100 V 50/60 Hz 18 VA, output DC 10 V 850 mA, with the outer sleeve positive and the centre pin negative.[1] The North American SNES takes the same 10 V DC from its SNS-002.[2]

DC input jack
Contact Function
Outer sleeve +10 V DC
Centre pin 0 V / ground

Check the polarity before you trust any replacement supply. Centre-negative barrel jacks are unusual, and a centre-positive supply of the right voltage will be connected backwards.

Never fit a PAL SNES supply to a Super Famicom. The European SNSP machine takes 9 V AC and rectifies it internally; the Super Famicom expects DC that has already been rectified.[2] The same warning applies in reverse to NES adapters, which are also AC.

What the console does with it

Inside, the 10 V passes through a series diode โ€” so the internal rail sits nearer 9 V โ€” and then splits two ways:[2]

  • A 7805 regulator produces the single +5 V logic rail. The CPU, PPUs and APU run from this and nothing else. It is U12 on SHVC-CPU-01, SNS-CPU-GPM, SNS-CPU-RGB and SNS-CPU-APU boards, and U9 on the 1CHIP and SNN boards.[3]
  • The unregulated ~9 V feeds the audio amplifier only. The console will run with that rail missing โ€” you simply get no sound.[2]

There is no 3.3 V rail and no 12 V rail in a Super Famicom. If you are looking for one, you are looking for something that is not there.

The fuse

Nintendo's diagnostic table lists a defective F1, a 1.5 A fuse as the first probable cause of a dead console, ahead of the regulator.[4] Check it before anything else, and replace like for like.

Nintendo's diagnostic table

Transcribed from Nintendo's own service literature. The probable causes are in Nintendo's order of priority, which is itself useful information โ€” Nintendo put the cartridge connector at the top of three separate faults.[4]

Nintendo prefaces it: before attempting any repair, strip the unit and inspect the PCB thoroughly for damaged or missing components and traces, solder defects, dirt and corrosion.

Control deck โ€” malfunctions and probable causes
Malfunction Probable causes, in order
Solid colour screen (a black screen counts here) 62-pin connector; sound module; poor solder; U1 (CPU); U3 (PPU2); U6 (WRAM); U2 (PPU1); U7 (RGB encoder); X1 (21 MHz oscillator); U8 (CIC)
Scrambled video images 62-pin connector; poor solder; U3 (PPU2); U1 (CPU); U2 (PPU1); U4 or U5 (256K SRAM)
Distorted or no sound Sound module; connector P5; U1 (CPU); U10 (amplifier); Q18
No reset (the system reset line, not the button) U8 (CIC); X2 (4 MHz oscillator); U9 (74HCU04)
Poor or no colour TC1 โ€” master clock frequency must be adjusted to 21.47727 MHz (NTSC) or 17.734475 MHz (PAL); U3 (PPU2); U7 (RGB encoder); X1 (21 MHz oscillator)
No power F1 (1.5 A fuse); D1; T1 (line filter); U12 (7805 regulator); VA1 (surge absorber); Q18; P3 (power switch)
Snowy screen RF modulator
Intermittent or no controller operation Front unit PCB assembly; FFC harness (flat cable); connector P2; U1 (CPU)
Frozen screen or erratic program operation 62-pin connector; poor solder; U1 (CPU); U3 (PPU2); U2 (PPU1)
Ejector will not eject game paks Early-version ejector โ€” Nintendo's instruction was to replace on customer complaint only

Nintendo notes that a few of the power-section parts were eliminated over the machine's production life, so not every board has a D1, T1, VA1 or Q18.[4]

TC1 is a trimmer, and it is adjustable. If a console has poor or no colour and everything else checks out, Nintendo's own remedy is to set the master clock to 21.47727 MHz on an NTSC or Japanese machine, or 17.734475 MHz on a PAL one, at TC1. Korth's hardware reference gives the same PAL crystal figure independently.[4][2]

The cartridge connector

The cartridge slot is a 62-pin edge connector and it is the first thing Nintendo blames for three of the ten faults above.[4][2]

Nintendo's own instruction was blunt: "Do not attempt to clean 62 pin connectors; they should be replaced."[4] That was written for warranty service centres with a parts bin, and it is worth reading as a statement of how much Nintendo trusted cleaning rather than as advice for a modern restorer with no source of new connectors. In practice, cleaning is what people do and it usually works โ€” but if a console keeps coming back after cleaning, Nintendo's view was that the connector itself was the problem.

In contrast to the NES-001, the Super Famicom connector is a conventional edge connector, so inserting and removing a cartridge does wipe the contacts. That is why the Super Famicom does not have the NES's reputation for needing constant attention.

  • Clean the cartridge contacts as well as the slot. A cartridge with tarnished contacts will dirty a clean console.
  • Isopropyl alcohol on a lint-free swab or a contact-cleaning card. Never metal polish and never an abrasive on gold plating.
  • Inspect for bent pins and for cracked solder joints where the connector meets the mainboard.

Connectors and ports

External connectors
Connector Detail
Cartridge slot 62-pin edge connector
Controller ports (ร—2) Proprietary 7-pin connector โ€” not a mini-DIN, despite the resemblance
AV Multi Out 12-pin Nintendo Multi Out
DC input Barrel jack, outer sleeve positive
Expansion port (underside) Rarely used; keep the original cover fitted

Multi Out pinout

Useful when chasing a video fault or building a cable.[2]

AV Multi Out
Pin Signal Pin Signal
1 RGB red 7 S-Video Y (luminance)
2 RGB green 8 S-Video C (chroma)
3 Composite sync (H/V) 9 Composite video
4 RGB blue 10 +5 V DC
5 Ground (video) 11 Audio left
6 Ground (audio) 12 Audio right

Red, green and blue carry a 1 V DC offset with 1 V peak-to-peak of video into 75 ฮฉ; sync, luminance, chroma and composite are 1 V peak-to-peak into 75 ฮฉ; the audio pins are 5 V peak-to-peak. On cost-reduced models pins 1โ€“4 and 7โ€“8 are reported as not connected, though they can be restored with modifications on the mainboard.[2]

Cleaning connectors

  • Contact cleaner or isopropyl alcohol on a lint-free swab; let it dry before powering up.
  • A fibreglass pen or a soft eraser on stubborn corrosion on edge contacts โ€” with care, and never on gold you want to keep.
  • Reseat the Multi Out and controller plugs a few times to wipe the contacts.
  • Reflow the solder on the controller ports and the Multi Out if faults are intermittent. Nintendo lists "poor solder" as a probable cause of four separate symptoms.[4]

Yellowed plastic

The Super Famicom's upper shell is the machine's most recognisable ageing problem. The grey ABS discolours unevenly, commonly with the top shell affected far more than the base and often in patches rather than uniformly.

Treatment is possible; see Retrobrite for the chemistry, the procedure and its risks. Two things worth knowing before you start:

  • The discolouration is in the body of the plastic, not on the surface, so cleaning will not touch it.
  • Over-treated ABS becomes brittle and the finish goes chalky. Watch the temperature and the exposure time, and stop early rather than late.

The coloured buttons, the cartridge slot dust flap and the base are usually less affected than the top shell, so treating the whole case uniformly can leave you with a mismatch you did not have before.

Capacitors

Most of the electrolytics in a Super Famicom are surface-mount parts, which is what makes this machine worth checking rather than ignoring: an SMD capacitor that has begun to leak hides the evidence underneath its own body, and the corrosion is only visible once the can is off.[5]

That said, the Super Famicom is not in the class of machines where recapping is mandatory. Open it, look, and act on what you find.

The original SHVC-CPU-01 board carries thirteen electrolytics: two 47 ยตF radials on the SHVC-SOUND module, ten surface-mount parts on the mainboard, and a 1000 ยตF 25 V radial reservoir on the DC input. Later revisions differ substantially โ€” see Super Famicom Capacitor Replacement Guide for the full per-revision lists and for the PAL C59 bipolar issue.[3]

Symptoms that justify pulling the board:

  • Buzzing, distorted or missing audio
  • Unstable video, rolling or colour shift
  • Random resets or failure to power on
  • Any visible brown, yellow or white residue around a capacitor, or green discolouration on the pads

Cleaning

Case and controllers

  • Damp microfibre cloth and mild detergent on the shell. No abrasives.
  • Controller ports: soft brush and isopropyl alcohol; a wooden cocktail stick for anything lodged.
  • Open controllers with a Phillips driver, wash the button caps and D-pad in warm soapy water and dry them thoroughly, then clean the PCB contacts with isopropyl alcohol. Replace the conductive pads if buttons stay dead.

Inside

  • Unplug the console and let it sit before opening it.
  • The shell screws are 4.5 mm Gamebit security screws.
  • Anti-static brush and compressed air on the board; isopropyl alcohol and a soft toothbrush on corrosion.
  • Keep moisture away from the cartridge connector and the sound module.

Tools

  • 4.5 mm Gamebit driver, Phillips drivers
  • Digital multimeter
  • Fine-tip temperature-controlled soldering iron, flux, desoldering braid or pump
  • Hot air station if you are replacing surface-mount capacitors
  • Isopropyl alcohol (99 %), anti-static brush, lint-free swabs
  • Contact cleaner
  • Plastic spudger

See Recommended Tools.

Preventive maintenance

  1. Confirm the adapter is DC and centre negative before connecting it.
  2. Clean the cartridge and the slot when games start needing a second insertion.
  3. Reseat the AV and controller plugs periodically.
  4. Open the case annually and look under the shield for capacitor residue.
  5. Reflow the regulator, Multi Out and controller port joints if intermittents appear.
  6. Keep the console out of direct sunlight โ€” the plastics are the part most likely to be ruined by storage.

References

  1. โ†‘ Famicom World, "Famicom Power Adaptor" โ€” https://famicomworld.com/workshop/tech/famicom-power-adaptor/ . HVC-002 rating plate: AC 100 V 50/60 Hz 18 VA in, DC 10 V 850 mA out, centre negative. Regional variants HVC-002 (HKG), AC 200 V 50 Hz 17 W, and HVC-002 (TPE), AC 110 V 60 Hz 18 VA, carry the same DC output.
  2. โ†‘ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Martin Korth, fullsnes โ€” SNES hardware specifications โ€” https://problemkaputt.de/fullsnes.htm . Sections "SNES Power Supply" and "SNES Audio/Video Connector Pinouts". Source for the 10 V DC 850 mA NTSC/Japanese supply, the 9 V AC PAL supply, the input diode drop, the 7805 producing the single +5 V logic rail, the audio amplifier running from the unregulated rail, and the 12-pin Multi Out pinout.
  3. โ†‘ 3.0 3.1 Console5 TechWiki, SNES โ€” https://wiki.console5.com/wiki/SNES . Secondary source: a community wiki compiled from physical boards. Used for the per-revision chip maps, the position of the 7805 regulator, capacitor lists, and its transcription of Nintendo's Control Deck diagnostic table.
  4. โ†‘ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Nintendo service literature, Control Deck diagnostic table, transcribed by Console5 from Manual Tรฉcnico do Super NES Rev. 01-94 (pt-BR), which covers the SHVC and GPM boards, controllers, Super Scope 6 and mouse. Reproduced at https://wiki.console5.com/wiki/SNES . Source for the malfunction/probable-cause table, the F1 1.5 A fuse rating, the TC1 master-clock alignment figures, and the instruction not to clean the 62-pin connector.
  5. โ†‘ Bob, "Restoring A Super Nintendo", RetroRGB, 31 May 2020 โ€” https://www.retrorgb.com/restoring-a-super-nintendo.html . Used for the assessment that the SNES is not known for leaky capacitors, and that SMD leakage is concealed under the capacitor body.
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