Editing Super Famicom Maintenance Guide (section)

== Self-inflicted faults ==

=== Not discharging C67 ===

'''Nintendo's first instruction in the disassembly procedure is not about screws.''' It is:

: 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="nintendodiag" />

C67 is the main reservoir on the DC input — 1000&nbsp;µF at 25&nbsp;V on Japanese and North American boards, 2200&nbsp;µF at 25&nbsp;V on PAL ones. It holds its charge after the adapter comes out, and it will dump that charge into whatever completes the circuit while you are working on the board. Flicking the power switch on with the adapter unplugged empties it through the console's own load, which costs nothing and takes a second.

GPM boards have no C67; the instruction does not apply to them.<ref name="nintendodiag" />

=== Cleaning the 62-pin connector with an abrasive ===

Nintendo's position was that the connector should be replaced rather than cleaned. Whatever you think of that, the one thing that is certainly wrong is taking an abrasive to the gold plating — once it is through, oxides form and will then transfer to every cartridge you insert.

=== Fitting a centre-positive supply ===

The DC jack is centre '''negative'''. A correctly-rated 10&nbsp;V supply with the usual centre-positive polarity is connected backwards.