Editing Atari 400 Capacitor Replacement Guide (section)

== Recapping procedure ==

{{Warning|The power supply PCB is fed from a transformer, but its ON/OFF switch (S203) opens the '''9 V AC''' input, and the board carries that AC as far as the rectifier diodes CR206–CR209. Unplug the adaptor at the wall before working on the board, and remember that C209 (4700 µF) can hold a charge after power-off — discharge it through a resistor before touching the board.}}

# Unplug the adaptor and all peripherals.
# Open the case and lift out the power supply PCB. Note that the '''power interlock switch S202''' is on this board; it cuts power when the cartridge cover is lifted, so the machine will appear dead on the bench with the lid off.<ref name="fsm" />
# Photograph and label every connector before disconnecting: J201 (20-pin socket to the motherboard), J202 (13-pin SIO), J203 (phono) and J204 (power jack).
# Desolder each capacitor with braid or a pump. Take care with the pads around C209 — it is the largest can and its pads carry the full rectified current.
# Clean the pads with isopropyl alcohol and check for lifted traces, particularly if electrolyte has already leaked.
# Fit the new capacitors observing '''polarity'''. A higher voltage rating than the original is always acceptable; a lower one never is.
# Reassemble, then verify the rails before fitting the cards back (see below).