Electro-Mechanical Pinball Repair For Dummies

 

START-UP SEQUENCE - Gottlieb 1960s to 1970s

 
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Inserting a coin or pressing the coin door start button activates the "S" (Start) Relay. The Start Relay will lock on from its own switch and a score motor switch.

 
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The "S" (Start) Relay will energize the main Hold Relay to illuminate the game ( if this is the first game after power-on).

 
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The "S" Relay will start the score motor running.

 
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The "S" Relay and the score motor increment the total play meter.

 
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The "SB" Relay (the secondary start relay) is activated through the score motor. The "SB" Relay energizes the Reset Relays ("Z1" and "Z2"). If a single or two player game, there may be only a "Z" Relay.

 
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The "Z2" Relay will reset the player 3 and 4 score reels to zero through the score relays (4 player games only). The "Z1" or "Z" Relay will reset the player 1 (and player 2 if present) score reels to zero through the score relays.

 
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The "SB" Relay resets the player unit through the Score Motor.

 
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The "U" Relay resets the reset bank (or Ax, Bx, relays on 1975 and later multi-player games and Ax on single players) through the score motor. It also resets the bonus unit or drop target banks (if the game has these). On multi-player games, inserting more coins or pressing the coin door start button activates the "PBx" Relay, through the Score Motor. The "x" represents the player number (from two to four).

 
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If the ball is in the Outhole, the "O" Relay activates. The "O" Relay, through the score motor and a switch on Relay "XB", will kick the ball to the shooter lane. Note: the "O" Relay will not activate unless the bonus unit (if the game has one) is reset to zero (there is a bonus unit zero position switch).

 
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When the ball re-enters the Outhole after game play, the "P" Relay kicks the ball back to the shooter lane. Switches on the "XB", "ZB", "P" Relays and some score motor switches advances the player unit (if present) and player relays ("PBx").

 

 

START-UP SEQUENCE - Gottlieb 1975 to 1978

 

Starting in 1975 with Fast Draw/Quick Draw the reset bank was replaced on multi-player games with Ax (reset control), Bx (last ball), and sometimes Cx/Dx relays and a Coin stepper unit. Single players got just an Ax relay.Almost every Gottlieb EM with a reset bank has an "S" start relay (single and multi-player games.) When this relay gets activated (by pressing the coin door start button), the game goes through its start-up sequence.

 
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Inserting a coin or pressing the coin door start button (Gottlieb calls this the "replay" button) activates the "S" (start) relay. The start relay will lock on from its own switch and a score motor switch.

 
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The "S" relay will start the score motor running

 
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The "S" relay and the score motor increment the total play meter.

 
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On a 4 player game, the coin unit (next to the chime box) will decrement four times to the home (zero) position, and then kick up one position (to the 1 player position). Note if players 1 & 4 are lit on the backglass, the coin unit is not stepping up from the zero to one player position.

 
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The "S" relay energizes the Ax relay through the Bx (Last Ball) relay (sometimes), but always thru a switch on the "S" relay, "U" relay, and score motor switch at 2C. This should energize the Ax relay.

 
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The "R" hold relay pulls in and stays in, this turns off power to the Game Over relay (which stays energized when a game is finished).

 
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On a 4-player game, the Player Unit in the backbox increments until it reaches the Z1 position. The Player Unit stops and the Z1 relay in the backbox energizes. The score motor resets the player 1&2 score reels through the Z1 relay. When all eight score reels are at "zero", the Z1 relay de-energizes and a normally closed switch on Z1 (very top switch, looks un-natural) allows the player control unit to increment to the Z2 position.

 
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On a 4-player game, the Player Unit stops and the Z2 relay in the backbox energizes. The score motor resets the player 3 and 4 score reels through the Z2 relay. When all eight score reels are at "zero", the Z2 relay de-energizes and a normally closed switch on Z2 (very top switch, looks un-natural) allows the player control unit to increment to the "home" position (this is the "player 1, ball 1" position). (On a 4-player game there is a player unit switch stack for each player. This controls which set of score reels will score in the game.)

 
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On a 2-player game there are no Z1 and Z2 relays. Instead the player unit uses two switch stacks (which would be the player3 and player4 stacks) and the score motor to reset all the score reels, instead of the Z1/Z2 relays and the score motor.

 
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Player unit is now at the "home" position ("player 1, ball 1" position). This is the P5A and P5B switches on the player unit, which is the switch stack closest to the backglass with only 2 switches. This causes the Ax relay to reset and the bonus unit to reset (if the game has a bonus unit). Often the P5A and P5B switches are dirty/mis-adjusted which will not let the score motor stop running.

 
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If the ball is in the outhole, the "O" relay activates kicking the ball to the shooter lane. Note: the "O" relay will not activate unless the bonus unit (if the game has one) is reset to zero (there is a bonus unit zero position switch).

 
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The ball passes over a trough switch as it is kicked from the outhole, which de-energized the "first ball" relay. Now the game will score. If this switch is closed after the "first ball" relay is de-energized, it will advance the player unit.

 

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