Reading a schematic

Guide details
Topic	Skill
Applies to	Both
Difficulty	Medium
How often	—
Tools needed	Schematic or manual Multimeter

A schematic is a map of a circuit. It shows every part and how they connect. You don't need to understand electronics deeply to use one for troubleshooting.

Common symbols

Part	Letter	What to look for
Resistor	R	A zigzag line or a small rectangle
Capacitor	C	Two parallel lines; a curved or marked line (+) means it's polarized
Diode	D	A triangle pointing at a line (current flows toward the line)
Transistor	Q	A circle with three connections and an arrow
Chip (IC)	U or IC	A rectangle with numbered pins
Fuse	F	A small rectangle or S-shaped line
Ground	GND	A downward-pointing set of lines or a triangle

Reference designators

Every part has a label like R12, C5, or U3. The same label is printed on the circuit board, so you can find the part. Many arcade boards also use a grid (letters along one edge, numbers along the other), so a chip might be called "7F" for its location.

Values

• Resistors are in ohms: 4.7k = 4,700 Ω.
• Capacitors are in farads: 100µF (microfarads) or 0.1µF. Polarized capacitors also list a voltage, like 25V.

Following the circuit

• Lines are wires. A dot where lines cross means they connect; no dot usually means they don't.
• Labels like +5V or GND that appear in many places are all connected, even without a drawn line.
• Start at the problem (for example, a dead coil) and trace backward toward the power source, checking each part with a multimeter.

Where to find schematics

Original manuals usually include them. Check the game's page on this wiki for links shared by other users.