Editing Super Famicom Maintenance Guide (section)

== Power supply ==

'''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" — 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'' — SNES hardware specifications — 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>

{| class="wikitable styled-table" style="width:80%;"
|+'''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&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.

=== What the console does with it ===

Inside, the 10&nbsp;V passes through a series diode — so the internal rail sits nearer 9&nbsp;V — and then splits two ways:<ref name="fullsnes" />

* 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'' — 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 — you simply get no sound.<ref name="fullsnes" />

'''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.

=== The fuse ===

Nintendo's diagnostic table lists a defective '''F1''' as the first probable cause of a dead console, ahead of the regulator, and its parts list specifies an axial '''1.5&nbsp;A''' fuse.<ref name="nintendodiag">Nintendo / Playtronic, ''Manual Técnico do Super NES'', Rev. 01/94, hosted at [[Nintendo Super NES Technical Manual (Playtronic, Rev. 01-94)]]. Console diagnostic table, pp. 2-28 to 2-29; colour-fault tree, p. 2-26; general disassembly instructions for the console; GPM mainboard description; console parts list ("Fusível 1,5A SSTR Axial"; "Circuito Integrado 7805"; chip electrolytics 10&nbsp;µF/16&nbsp;V ×3, 33&nbsp;µF/25&nbsp;V ×2, 2.2&nbsp;µF/25&nbsp;V).</ref> Check it before anything else, and replace like for like.