Editing Super Nintendo General Maintenance

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[[File:Super Famicom (photo).jpg|thumb|300px|The Super Famicom. The Super Nintendo shares its architecture but not its board numbers.]]

This guide covers routine care, board identification and the board-level figures for the '''Super Nintendo Entertainment System''' — the North American '''SNS-''' boards, the European and Australian '''SNSP-''' boards and the SNES Jr / SNES mini '''SNN-''' board. The Japanese '''SHVC-''' boards are covered on [[Super Famicom Maintenance Guide]], and the two families are not interchangeable at the designator level: an SHVC-CPU-01 has no SNS-CPU-GPM-02 in it.

Everything here that is a number comes from Nintendo's own service literature — the Playtronic ''Manual Técnico do Super NES'' and the Japanese Famicom / Super Famicom / Game Boy service manual, both hosted on this wiki — or from a named community source that says where it got it.<ref name="playtronic">Nintendo / Playtronic, ''Manual Técnico do Super NES'', Rev.&nbsp;01/94, hosted at [[Nintendo Super NES Technical Manual (Playtronic, Rev. 01-94)]]. Console theory of operation (pp.&nbsp;2-1 to 2-2): the AC adapter supplies 10&nbsp;V DC unregulated; the on-board supply section comprises a noise filter, reverse-current protection, the power switch, a spike suppressor, a ripple filter and the regulator, and produces a regulated Vcc of 5&nbsp;V and an unregulated Vs of 7&nbsp;V used by the audio amplifier; the system timing section feeds a 21&nbsp;MHz master clock to the CPU, PPU1, PPU2 and connector P1, and the CPU divides it by 6, 8 and 12 to give 3.58, 2.68 and 1.79&nbsp;MHz, with DMA always at 2.68&nbsp;MHz; the RESET section uses a 4&nbsp;MHz oscillator, a 74HCU04 hex inverter, the CIC and the reset switch, and applies CIC reset to PPU2 first, then PPU1, then the CPU. Parts list: F1 a 1.5&nbsp;A SSTR axial fuse, U12 a 7805, X1 a 21.453666&nbsp;MHz (PAL-M) crystal, X2 a 4&nbsp;MHz ceramic oscillator, TC1 a 20&nbsp;pF trimmer, and the chip electrolytics 10&nbsp;µF/16&nbsp;V ×3, 33&nbsp;µF/25&nbsp;V ×2 and 2.2&nbsp;µF/25&nbsp;V ×1. Adjustment and fault-finding: TC1 set to 21.453666&nbsp;MHz; the 4&nbsp;MHz CIC clock acceptable between 3.8 and 4.2&nbsp;MHz. Game Pak test procedure: where the cartridge carries a save battery, the reading must be between 2.7 and 3.2&nbsp;V DC. Disassembly: switch the console on with the AC adapter disconnected to discharge C67 before opening it; six security screws in the lower case; the sound module comes off with two screws. Console diagnostic table, pp.&nbsp;2-28 to 2-29, and the instruction not to clean 62-pin connectors but to replace them. GPM section (pp.&nbsp;3-1 ff.): GPM is the Ground Plane Method, a PCB process putting a base layer between the track layout and the solder mask; the redesign removed the lower RF shield, shortened the PCB, deleted C67 and the 4&nbsp;MHz oscillator, built the sound module circuit onto the mainboard, made TC1 a through-hole part, and removed the cartridge lock bar from the upper housing in favour of a warning label. IC handling notes (p.&nbsp;8-2): do not measure ICs with a multimeter or signal tracer.</ref><ref name="famsm">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), issued 7 August 1992, hosted at [[Nintendo Famicom Service Manual]]. HVC section, pp.&nbsp;2–10: AC adapter rated DC&nbsp;10&nbsp;V with a normal no-load output of DC&nbsp;13.5&nbsp;±&nbsp;1.5&nbsp;V; power-circuit block diagram showing a 7805 with 13–14&nbsp;V in and 5&nbsp;V out; the three solder points that need reinforcing around the DC jack; "before you decide it is a fault" table, p.&nbsp;3; controller fault symptoms, p.&nbsp;4; exploded parts diagrams, pp.&nbsp;7–9. SHVC section, pp.&nbsp;11–15: power-switch harness polarity, red lead to +, black to −; SHVC power circuit, 7805 with 13–14&nbsp;V in and 5&nbsp;V out; Super Famicom repair price list (1.5&nbsp;A SSTR axial fuse, 7805, 62-pin card connector supplied as an upper and a lower half, sound module).</ref> Where a figure is not in one of those, it is not given here.

== Identify the board first ==

Read the revision off the PCB silkscreen. It is printed along an edge of the mainboard and it, not the case, decides which capacitor list, which regulator designator and which clock figure apply to your machine.

{| class="wikitable styled-table" style="width:95%;"
|+'''Super Nintendo mainboard families'''
! Silkscreen !! Market !! What it is
|-
| '''SNS-CPU-GPM-01''', '''SNS-CPU-GPM-02''' || North America || Ground-plane construction. Nintendo's own redesign of the original layout
|-
| '''SNS-CPU-RGB-01''', '''SNS-CPU-RGB-02''', '''SNS-CPU-APU-01''' || North America || Renumbered board; the C57–C67 range of the earlier boards does not carry over
|-
| '''SNS-CPU-1CHIP-01/-02/-03''' || North America || CPU and both PPUs merged into one package
|-
| '''SNSP-CPU-01''', '''SNSP-CPU-02''' || Europe, Australia || 9&nbsp;V AC input, rectified on the board. Carries the S-CLK
|-
| '''SNSP-CPU-1CHIP-01/-02''' || Europe, Australia || PAL single-chip revision
|-
| '''SNN-CPU-01''' || All markets || SNES Jr / SNES mini. No RF modulator, no eject mechanism
|-
| ''SHVC-CPU-01'' and later SHVC boards || Japan || Super Famicom — see [[Super Famicom Maintenance Guide]]
|}

=== GPM and 1CHIP are unrelated ===

These two get conflated constantly, and they are not the same kind of change.

'''GPM''' stands for '''Ground Plane Method''' — it is a PCB manufacturing process, documented by Nintendo in its own manual, which puts a base layer between the track layout and the solder mask. The benefit was that the lower RF shield could be deleted. Along with the process change came a shorter PCB, the removal of '''C67 and the 4&nbsp;MHz oscillator''', the sound module circuitry built directly onto the mainboard instead of on a daughtercard, TC1 changed to a through-hole part, and the cartridge lock bar deleted from the upper housing in favour of a warning label.<ref name="playtronic" /> It is an early-to-mid production change and it has nothing to do with video quality.

'''1CHIP''' is a much later silicon change: the CPU and both picture processors were merged into a single package, the '''S-CPUN'''.<ref name="fullsnes">Martin Korth, ''fullsnes'' — SNES hardware specifications — https://problemkaputt.de/fullsnes.htm . Sections "SNES Power Supply", "SNES Timing Oscillators", "SNES Chipset" and "SNES Cartridge Slot Pinouts". NTSC and Japanese consoles take 10&nbsp;V DC at 850&nbsp;mA through a series diode; PAL consoles take 9&nbsp;V AC and rectify it on board at DB1. A 7805 produces the only logic rail, +5&nbsp;V, and the CPU, PPU and APU run solely from it; the unregulated rail feeds only the audio amplifier, and the console runs without it but silently. Timing: NTSC crystal 21.4772700&nbsp;MHz (X1 type D214K1), NTSC master clock 21.4772700&nbsp;MHz; PAL crystal 17.7344750&nbsp;MHz (X1 type D177F2), PAL master clock 21.2813700&nbsp;MHz synthesised by the S-CLK as 17.7344750&nbsp;×&nbsp;6/5; APU oscillator 24.576&nbsp;MHz. Chipset list for board SNSP-CPU-01 (U1 S-CPU, U2 S-PPU1, U3 S-PPU2, U4/U5 32K×8 video SRAM, U6 W-WRAM, U7 S-ENC, U8 CIC, U9 74HCU04 fitted on NTSC boards only, U10 AN1324S quad amplifier, U11 T529D reset IC, U12 7805, U13 S-SMP, U14 S-DSP, U15/U16 sound SRAM, U17 µPD6376 DAC, U18 S-CLK on PAL only, TC1 red trimmer, F1 1.5&nbsp;A fuse, T1 TDK dual-loop filter, DB1 bridge on the AC version only, VR1 ZNR surge absorber) and for the cost-reduced single-chip board (U1 S-CPUN, U2 S-APU, U3 S-WRAM B, U7 S-RGB A, U8 F411B CIC, U9 7805, U10 S-MIX A). Cartridge slot: 62 pins on a non-standard 2.5&nbsp;mm pitch, CIC clock 3.072&nbsp;MHz on later consoles or 4.00&nbsp;MHz on older ones. Also the source for the anti-eject lever fitted to the power switch of earlier consoles.</ref> That is the revision sought after for its video output. A GPM board is not a 1CHIP board, a 1CHIP board is not a GPM board, and a console advertised as "1CHIP" because its silkscreen says GPM is mislabelled.

== Power ==

'''North American consoles take 10&nbsp;V DC at 850&nbsp;mA, centre negative.''' Centre negative means the '''centre pin is 0&nbsp;V and the outer sleeve is +10&nbsp;V'''. European and Australian consoles take '''9&nbsp;V AC''' into the same style of jack and rectify it on the board at DB1. The two are not interchangeable in either direction, and a correctly rated 10&nbsp;V centre-''positive'' supply is connected backwards.<ref name="fullsnes" />

'''The supply is unregulated, so a high off-load reading is normal.''' Nintendo specifies the Famicom-family adapter as reading '''DC 13.5&nbsp;±&nbsp;1.5&nbsp;V with no load''', and its power-circuit block diagram labels the 7805's input arm '''13–14&nbsp;V'''.<ref name="famsm" /> A meter showing 13&nbsp;V on the barrel of a "10&nbsp;V" adapter is not a reason to throw the adapter away.

{| class="wikitable styled-table" style="width:95%;"
|+'''Supply and rails'''
! Item !! Figure !! Note
|-
| Adapter, NTSC || 10 V DC, 850 mA, '''centre negative''' || Centre pin 0 V, outer sleeve +10 V<ref name="fullsnes" />
|-
| Adapter, PAL || 9 V AC || Rectified on the board at DB1<ref name="fullsnes" />
|-
| Adapter, no load || 12.0–15.0 V DC || Nintendo's figure is 13.5&nbsp;±&nbsp;1.5&nbsp;V and it is '''normal'''<ref name="famsm" />
|-
| '''F1''' || 1.5 A, SSTR axial || Both Nintendo parts lists carry it; fullsnes records the fitted part as "SOC, 1.5A"<ref name="playtronic" /><ref name="famsm" /><ref name="fullsnes" />
|-
| Regulator || '''7805 at U12''' — '''U9''' on the 1CHIP and SNN boards || 13–14 V in, 5 V out<ref name="playtronic" /><ref name="famsm" /><ref name="fullsnes" />
|-
| '''Vcc''' || 5.0 V || The '''only''' regulated rail. CPU, both PPUs and the APU run from it and from nothing else<ref name="playtronic" />
|-
| '''Vs''' || unregulated, 7 V by Nintendo's figure || Feeds '''only''' the audio amplifier. A console with Vs missing plays silently and otherwise normally<ref name="playtronic" />
|}

'''There is no +12&nbsp;V rail, no 3.3&nbsp;V rail and no save battery anywhere in a Super Nintendo.''' Nintendo's description of the supply section is a noise filter, reverse-current protection, the power switch, a spike suppressor, a ripple filter and the regulator — and two outputs, Vcc and Vs.<ref name="playtronic" /> '''"IC601" is not a designator on any of these boards'''; the regulator is U12, or U9 on the later single-chip boards.

Save batteries are in the '''cartridges'''. Nintendo's Game Pak test procedure has the technician measure the cartridge battery and expects '''2.7 to 3.2&nbsp;V DC'''; below that, saves start being lost.<ref name="playtronic" />

== Chip map ==

Nintendo's diagnostic tables are written against U-numbers, so it is worth knowing what they are before you follow one. This is the map for the PAL '''SNSP-CPU-01'''; the North American SNS-CPU boards of the same generation use the same numbering except that they have no S-CLK and no bridge rectifier.<ref name="fullsnes" />

{| class="wikitable styled-table" style="width:95%;"
|+'''SNSP-CPU-01 — component map'''
! Designator !! Part !! Function
|-
| U1 || Nintendo S-CPU A (5A22) || Main CPU, 65C816 core with mapper, DMA and joypad interface
|-
| U2 || Nintendo S-PPU1 (5C77) || Picture processor 1
|-
| U3 || Nintendo S-PPU2 (5C78) || Picture processor 2
|-
| U4, U5 || 32K × 8 static RAM || Video RAM
|-
| U6 || Nintendo W-WRAM || Work RAM
|-
| U7 || Nintendo S-ENC || RGB to composite encoder
|-
| U8 || Nintendo F413 || CIC lockout
|-
| U9 || 74HCU04 hex inverter || '''NTSC boards only.''' Clock inverter for X1 and the CIC
|-
| U10 || AN1324S (LM324 equivalent) || Audio quad amplifier — runs from Vs
|-
| U11 || T529D || Reset / voltage-detector IC
|-
| U12 || 7805 || +5 V regulator
|-
| U13 || Nintendo S-SMP || Sound CPU, SPC700 core
|-
| U14 || Nintendo S-DSP || Sound DSP
|-
| U15, U16 || 32K × 8 static RAM || Audio RAM
|-
| U17 || NEC µPD6376 || Dual 16-bit audio DAC
|-
| U18 || Nintendo S-CLK || '''PAL boards only.''' Synthesises 21.2813700 MHz and 4.43 MHz from X1
|-
| TC1 || Red trimmer capacitor || Master clock adjustment
|-
| X1 || D177F2 (PAL) / D214K1 (NTSC) || Master crystal
|-
| X2 || 24.576 MHz || APU clock
|-
| F1 || 1.5 A axial fuse || Supply input
|-
| T1 || TDK dual-loop filter || Supply input
|-
| DB1 || Bridge rectifier || '''AC (PAL) boards only'''
|-
| VR1 || ZNR surge absorber || Supply input
|}

'''U9 is a 74HCU04 on NTSC boards and is simply absent on PAL boards''', because the S-CLK does that job instead.<ref name="fullsnes" /> A PAL owner following an NTSC fault tree to "U9, the hex inverter" will be looking at an empty footprint — or, on a 1CHIP or SNN board, at the 7805.

On the cost-reduced single-chip boards the map collapses: U1 is the S-CPUN containing CPU, both PPUs and the S-CLK, U2 is the S-APU containing the S-SMP, S-DSP and sound RAM, U3 is the S-WRAM B, U7 is the S-RGB A, U8 is the F411B CIC, '''U9 is the 7805''' and U10 is the S-MIX A.<ref name="fullsnes" />

== Clocks ==

The master clock is '''region specific''' and the wrong target figure will send you chasing a fault that is not there.

{| class="wikitable styled-table" style="width:85%;"
|+'''Master clock by television standard'''
! Standard !! Crystal !! Master clock
|-
| NTSC (North America, Japan) || 21.4772700 MHz at X1 || '''21.47727 MHz'''
|-
| PAL (Europe, Australia) || 17.7344750 MHz at X1 || '''21.281370 MHz''', synthesised by the S-CLK
|-
| PAL-M (Brazil, Playtronic) || 21.453666 MHz at X1 || '''21.453666 MHz'''
|}

TC1 trims the master oscillator, and Nintendo's remedy for a colour fault that survives everything else is to set it to the region-correct frequency; if it will not adjust or will not hold, replace TC1 and then X1.<ref name="playtronic" /><ref name="fullsnes" /> '''Do not apply the Brazilian figure to a European or North American console.'''

The CIC runs from a separate '''4&nbsp;MHz''' ceramic oscillator at X2 on the earlier boards, and Nintendo gives the acceptable window as '''3.8 to 4.2&nbsp;MHz'''.<ref name="playtronic" /> On later consoles the CIC clock is derived instead as 3.072&nbsp;MHz from the 24.576&nbsp;MHz APU oscillator.<ref name="fullsnes" />

The reset order is deliberate: the CIC's reset reaches '''PPU2 first''', which introduces a delay, then PPU1, then the CPU, so that both picture processors are running before the CPU is released.<ref name="playtronic" /> A fault that holds PPU2 in reset therefore stops the whole machine and looks exactly like a dead CPU.

== Opening the console ==

'''Nintendo's first disassembly instruction is not about screws.'''

: Before disassembling, switch the console's power supply ON with the AC adapter disconnected, in order to discharge capacitor C67. This capacitor is known to discharge during maintenance, causing damage to components.<ref name="playtronic" />

C67 is the reservoir on the supply input and it holds its charge after the adapter comes out. Flicking the power switch with nothing plugged in empties it through the console's own load. GPM boards have no C67 and the later boards carry the reservoir under a different designator — see [[Super Nintendo Capacitor Replacement Guide]] — but the step costs nothing and you do not always know which board you have until it is open.

* '''Six''' security screws in the lower case, taking a '''4.5&nbsp;mm Gamebit''' driver.<ref name="playtronic" />
* The sound module, where fitted, comes off with '''two''' screws on its far side and lifts straight up.<ref name="playtronic" />
* SNS-CPU-1CHIP, SNSP-CPU-1CHIP and SNN-CPU boards have no sound module to remove — the sound circuitry is on the mainboard.<ref name="fullsnes" />

=== Do not meter the ICs ===

Nintendo's own IC handling notes say plainly that a multimeter or signal tracer applies a significant voltage to determine resistance and will damage the device; if you must measure an IC at all, use the lowest resistance range and accept the risk.<ref name="playtronic" /> Probe supply pins and passives, not chips.

== The cartridge connector ==

A '''62-pin''' edge connector on a non-standard '''2.5&nbsp;mm''' pitch, taking a 1.2&nbsp;mm board.<ref name="fullsnes" /> Nintendo's diagnostic table puts it at the head of the probable causes for three separate faults, and Nintendo's instruction to its own service centres was blunt: '''do not clean 62-pin connectors, replace them.'''<ref name="playtronic" />

That was written for centres with a parts bin, and Nintendo supplied the connector as two service parts, an upper and a lower half.<ref name="famsm" /> For a modern restorer with no source of new connectors, cleaning is what there is, and it usually works — but if a console keeps coming back after cleaning, Nintendo's view was that the connector itself was the problem.

* Clean the '''cartridge''' contacts as well as the slot; a tarnished cartridge will re-dirty a clean console.
* Isopropyl alcohol on a lint-free swab or a contact-cleaning card. Never metal polish, never an abrasive on gold plating — once you are through the plating, oxides form and then transfer to every cartridge you insert.
* Inspect for bent pins and for cracked joints where the connector meets the mainboard. Nintendo lists "poor solder" as a probable cause of four separate symptoms.<ref name="playtronic" />

Unlike the NES-001, this is a conventional edge connector, so inserting and removing a cartridge wipes the contacts. That is why the SNES does not share the NES's reputation for needing constant attention.

== 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, dry them thoroughly, and clean the PCB contacts with isopropyl alcohol. Replace the conductive pads if buttons stay dead.

=== Inside ===
* Discharge the reservoir first, as above.
* Anti-static brush and compressed air on the board; isopropyl alcohol and a soft brush on corrosion.
* Keep moisture away from the cartridge connector and the sound module.

== Yellowed plastic ==

The North American SNES uses two greys that were never the same colour and have aged differently, so a "yellowed" console is often partly original two-tone. Compare the underside of a panel with its face before deciding anything has discoloured at all. European and Japanese shells are a single light grey and yellow more evenly.

Treatment is possible; see [[Retrobrite]] for the chemistry, the procedure and its risks. Two things worth knowing first:

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

== Capacitors ==

Most of the electrolytics on the SNS- and SNSP- boards are '''surface-mount''', which is what makes this machine worth opening rather than ignoring: an SMD capacitor that has begun to leak hides the evidence under its own body, and the corrosion only shows once the can is off.<ref name="retrorgb">Bob, "Restoring A Super Nintendo", RetroRGB, 31 May 2020 — https://www.retrorgb.com/restoring-a-super-nintendo.html . Used for the assessment that the SNES is not known for leaky capacitors, and that surface-mount leakage is concealed under the capacitor body until the can is removed.</ref>

The SNES is nonetheless '''not''' a machine where recapping is mandatory. Open it, look, and act on what you find. 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 brown, yellow or white residue around a capacitor, or green discolouration on the pads

Per-revision lists are on [[Super Nintendo Capacitor Replacement Guide]]. See also [[Capacitor Failure Symptoms]].

== Self-inflicted faults ==

* '''Not discharging the reservoir before working on the board.''' Nintendo's own stated reason for the step is that the capacitor discharges during maintenance and damages components.<ref name="playtronic" />
* '''Fitting the front-unit flat cable the wrong way round.''' The unprinted face is the contact face. Reversed, you get dead controller ports on a console that is otherwise perfectly healthy.<ref name="famsm" />
* '''Reversing the power-switch harness.''' Nintendo marks + and − on the switch body and specifies the red lead to + and the black to −.<ref name="famsm" />
* '''Fitting a centre-positive supply.''' The jack is centre negative; a correctly rated 10&nbsp;V centre-positive adapter is connected backwards.
* '''Fitting a PAL adapter to an NTSC console or the reverse.''' One is 9&nbsp;V AC, the other 10&nbsp;V DC.<ref name="fullsnes" />
* '''Taking an abrasive to the cartridge connector.'''
* '''Metering the ICs.'''<ref name="playtronic" />

== Things that are not faults ==

* An adapter reading 13&nbsp;V or so off load. Nintendo's own figure is 13.5&nbsp;±&nbsp;1.5&nbsp;V.<ref name="famsm" />
* '''The 7805 running hot.''' It is dropping around 8&nbsp;V at whatever the console draws, and that is where the heat goes.
* '''The console switching off as a cartridge is pulled.''' Earlier consoles carry an anti-eject lever on the power switch that rides in a notch in the cartridge; on cartridges with a diagonally cut notch it switches the console off as the cartridge comes out.<ref name="fullsnes" /> Nintendo deleted the lock bar on GPM machines and substituted a warning label.<ref name="playtronic" />
* '''No sound module on the board.''' GPM, 1CHIP and SNN boards do not have one.<ref name="playtronic" /><ref name="fullsnes" />
* '''No C67.''' GPM boards do not have one.<ref name="playtronic" />

== Tools ==

* 4.5&nbsp;mm Gamebit driver, Phillips drivers
* Digital multimeter; a frequency counter or a scope if you are setting TC1
* Fine-tip temperature-controlled soldering iron, flux, desoldering braid or pump
* Hot air station for surface-mount capacitors
* Isopropyl alcohol (99&nbsp;%), anti-static brush, lint-free swabs
* Contact cleaner, plastic spudger

See [[Recommended Tools]].

== Preventive maintenance ==

# Confirm the adapter type and polarity before connecting it — DC and centre negative for an NTSC console, 9&nbsp;V AC for a PAL one.
# Clean the cartridge and the slot when games start needing a second insertion.
# Reseat the AV and controller plugs if the picture or a controller becomes intermittent.
# Reflow the DC jack, the Multi Out and the controller port joints if intermittents appear. Nintendo identifies three solder points around the DC jack as needing reinforcement.<ref name="famsm" />
# Keep the console out of direct sunlight — the plastics are the part most likely to be ruined by storage.

== Related pages ==
* [[Super Nintendo Entertainment System]]
* [[Super Nintendo Capacitor Replacement Guide]]
* [[Super Nintendo Troubleshooting Guide]]
* [[Super Famicom Maintenance Guide]]
* [[Nintendo Super NES Technical Manual (Playtronic, Rev. 01-94)]]
* [[Nintendo Famicom Service Manual]]
* [[SNES Schematic]]
* [[Retrobrite]]
* [[Capacitor Failure Symptoms]]

== References ==
<references />

[[Category:Nintendo]]
[[Category:Maintenance Guides]]