CPU Board LED Flash Codes, all revisions.
WPC-S and prior uses a "Dx" designation for its CPU LEDs. WPC-95 uses a "LED20x" designation.
D19/LED201 (blanking): at power-on should be ON for about 3 seconds (1 second on WPC-95), and then turn off and stay off. When D19/LED201 is on, the blanking circuit is disabled (and will not allow any coils to be energized).
D20/LED203 (diagnostic): After D19/LED201 turns off, D20/LED203 should stay flashing permanently while the game is turned on. This indicates the CPU is "running".
D21/LED202 (+5vdc): this LED should ALWAYS be on. It indicates the CPU has +5 volts DC power.
Problem Power-On CPU D20/LED203 (diagnostic) Flash Codes. If D20 does not flash continually, here are the flash codes diagnostics:
blinks ONE time: U6/G11 CPU game ROM bad
blinks TWO times: U8 CMOS RAM chip bad
blinks THREE times: U9 WPC custom chip bad (pre WPC-S), or G10 Security PIC chip bad (WPC-S and later)
WPC-S and Prior Driver Board LEDs, Test Points (TP), and Fuses.
For reference, TP5 is ground.
LED1/TP3: +12 volts DC switch matrix circuit. Should be always ON. If off, check fuse F115. This is often caused by a bad CPU board chip U20 (see the switch matrix section for more details). The AC Power originates at connector J101 pins 4,5 and 6,7. It then goes through fuse F114, bridge BR1, capacitors C6 and C7, LED6/TP8 (18 volts DC), diodes D1 and D2, voltage rectifier Q2, fuse F115, LED1/TP3 (12 volts DC), then to connector J114 pins 1,2. Also, just before diodes D1 and D2, the circuit splits to the LM339 chip U6, and LED2/LED3.
LED4/TP2: +5 volts DC digital circuit. Should be always ON. If off, game will not boot. Check fuse F113 (or bridge BR2 and capacitor C5). Though not likely to fail, there is also a voltage regulator LM323 at Q1, a LM339 chip at U6 ("zero cross"), and two 1N4004 diodes at D3 and D38. The AC Power originates at connector J101 pins 1 and 2. It then goes through fuse F113, bridge BR2, capacitor C5, voltage rectifier Q1, LED4/TP2 (5 volts DC), then to connector J114 pins 3,4. Note after fuse F113, the AC power also continues to diodes D3 and D38, and to LM339 chip U6. Then this "zero cross" power merges back into the +5 volt line before hitting connector J114.
LED5/TP7: +20 volts DC flashlamp circuit. Normally ON. Twilight Zone and later, this LED fades off when the coin door is opened. If off, check coin door and fuse F111 (or bridge BR4 and capacitor C11). The AC Power originates at connector J102 pins 1,2 and 3,4. It then goes through fuse F111, bridge BR4, capacitor C11, LED5/TP7 (20 volts DC), then to connector J107 pins 5,6 (and J106 and J108).
LED6/TP8: +18 volts DC lamp matrix circuit. Normally ON. If off, check fuse F114 (or bridge BR1 and capacitors C6, C7). Though not likely to fail, there is also a voltage regulator LM7812 at Q2, a LM339 chip at U6, and two 1N4004 diodes at D1 and D2. The AC Power originates at connector J101 pins 4,5 and 6,7. It then goes through fuse F114, bridge BR1, capacitors C6 and C7, LED6/TP8 (18 volts DC), diodes D1 and D2, voltage rectifier Q2, fuse F115, LED1/TP3 (12 volts DC), then to connector J114 pins 1,2. Also, just before diodes D1 and D2, the circuit splits to the LM339 chip U6, and LED2/LED3.
LED7/TP1: +12 volts DC power circuit (motors, relays, etc). Should always be ON. If off, check fuse F116 (or bridge BR5 and capacitor C30). The AC Power originates at connector J112 pins 1,2 and 3,5. It then goes through fuse F116, bridge BR5, capacitor C30, LED7/TP1 (12 volts DC), then to connector J118/J117/J116 pin 2.
TP6 (no LED): +50 volts for the coil. The AC Power originates at connector J102 pins 5,6 and 8,9. It then goes through fuse F112, bridge BR3, capacitor C8, TP6 (50-70 volts DC), then fuses F103/F104/F105 (and F102/F102), then to connector J107, J106 J108, and J109.
LED2 (no TP): This LED is not always installed. High/low line voltage sensor. Normally ON, but flickers with the playfield lamps.
LED3 (no TP): This LED is not always installed. High/low line voltage sensor. Normally OFF, but flickers with the playfield lamps.
