Scope.
This document is a repair guide for Electro-Mechanical (EM) coin opertated games made up to about 1978. This includes pinball games, pitch and bats (baseballs), bowlers, gun games, etc. Though pinball is stressed the most in this document, this information applies to most EM arcade games made from the 1930s to 1978. Electro-Mechanical (EM) means the game uses relays and switches, and does *not* use a computer CPU. No experience is assumed. Basic electrical knowledge is helpful, but even that is not necessary.

Updates of this document are available for no cost at http://www.marvin3m.com/fix.htm if you have Internet access. This document is part two of two (part one is here).

For parts, schematics, and repair sources please see the parts and repair sources web page.

Table of Contents

1. Getting Started:
1. Introduction
2. Necessary Tools
3. Parts to have On-Hand
4. Lubrication and Contact Cleaner Notes
5. Electrical Parts of an EM Game

2. Before Turning the Game On:

1. Check the Fuses and Fuse Holder
2. Check the Plug Connectors and Lamp Sockets
3. Switch Contacts
4. Score Reels
5. Stepper Units

3. When Things Still Don't Work:

1. The Check List
2. Typically What's Wrong
3. Gottlieb Reset Bank and Reset Relays
4. Score Motors
5. Start Up Sequences
6. Reading Schematics
7. Reading Schematics 2 & Fixing Game Features
8. Other Stories/Problems
9. Gottlieb Coin Doors: the Shocking Truth
10. Coils Explained: Testing Coils/Low Resistance Coils

4. Finishing Up:

1. Setting your EM to Freeplay
2. Cleaning and Waxing the Playfield
3. Playfield Rubber
4. Increasing EM Game Performance

So you're the impatient type, and couldn't stand to wade through all the above information and things to do. You want the bare essentials. Well this checklist is for you if your EM game doesn't work. Just follow this list...
1. Verify the power outlet the game is plugged into works.
2. Verify 110 volts is getting to the transformer. Thirty year old (or older) power cords can easily have breaks in them. Check the voltage with your digital multi-meter (DMM), on the input side of the transformer.
3. Check all fuses with your DMM. See the Check Fuses section. Check the fuse holders too.
4. Verify the power switch is functional (if it has one) and turned ON.
5. If a Gottlieb game, make sure the coin door is plugged in.
6. Check that there are credits on the credit wheel. If not, add some (manually if you must).
7. Try the coin door start button.
   If nothing happens and it's a Gottlieb:
   • See the Reset Bank section (but make sure the game has credits!)
   If the score motor continues to run:
   • If the game has score reels, see the Score Reel section. If either of the two "zero position" switches on any score reel is out of adjustment, the score motor will continue to run.
   • If the game does not have score reels, see the Stepper Unit section. If a stepper unit does not reset, the score motor can continue to run (actually this can happen on games with score reels too).
   • If a Gottlieb game, make sure the score motor "brake" switch (a single switch on the score motor that has *no* wires attached to it!) is hitting the metal rod as the score motor turns. The purpose of this "brake" switch is to make sure the score motor stops at an exact home position and doesn't "over run", and continue running endlessly.
   • Check the score motor's "home" switch (on Gottlieb's, usually at 1C or 4C). This switch is what turns off the score motor when it rotates to a "home" position every 120 degrees. Because of the score motor's electro-magnetic field collapse when the motor turns off, the score motor home switch gets a "blue arc" (easy to see when the score motor rotates!) every rotation of the score motor. This blue arc makes the home switch wear and pit easily, and go out of adjustment. If the home switch is out of adjustment or worn, this too can allow the score motor to "over run" a home position, and perhap never stop running!
8. If the game starts and:
   • blows a fuse. Either a coil is stuck on, or if a 70's Williams or Bally, see Bridge Rectifiers section.
   • a coil or score reel is stuck on, see the Score Relay Stuck On section.
   • certain features don't reset (like number of players, credit or ball number, etc.), see the Stepper Unit section.
   • certain game features don't work, see the Game Features section.

At this point you have cleaned and checked the score reels, score relays, and stepper units. But the game still doesn't work. Keep the faith, you are probably 75% done with your repair job at any rate!

Here's a list of some other common EM problems and their solutions:

• No credits on game.
  Trying to start a game with no credits? A lot of people do not set their games to free play (especially if you bought it from an old vender!). Move the credit wheel to one or more credits and try again. Sounds simple, but you would be surprised how often that gets by you...

• You plug the game in, but no there's no lights and no power.
  This is a real typical problem on a game that has been in storage for long periods of time.

  Did you check the fuses? Sounds simple, but we all usually forget to do this.

  On Gottlieb games (and many Bally and Williams games), after the power exits the main transformer, it goes to a "hold" relay in the bottom panel of the game. This relay usually has just one or two switches. If these contacts are dirty, no power will get to the rest of the game. Look for the most burnt relay in the bottom of the game cabinet, and that's probably the hold relay! It's on the entire time the game has power. Clean it's contacts. With the power on, manually activate the relay and look for lights.

  Bally and Williams games also use a latch relay for the game over circuit that has one switch which controls all light power to the game. If this one switch is dirty or mis-adjusted, the game just won't light up! Clean and check the game over relay switches.

  Power Switch and Power-On Lights?
  Also remember that pre-1970 EM's (especially Gottlieb's) usually don't have a power switch! On Gottlieb's in particular, you have to start a game to get the General Illumination (GI) lights to work. On Williams and Bally games (even as late as 1977), often pressing the left flipper button will turn the GI lights on.

  To by-pass the above "feature" of no GI when the game first powers on, I bend all the switches on the hold relay permanently ON. Then I disconnect one lead that goes to the hold relay coil itself. This make the GI on permanently, even when you first turn the game on. It also removes the power to the hold relay so it can't hum or get hot. There is a down side to this modification; if you shut the machine off in the middle of a game, when you turn it back on you'll still be in the middle of the last game (turning the machine off doesn't end the current game).

  On those non-power switch games, I always add a power switch. To do this, just cut the black lead from the power cord as it comes into the game (before it hits the fuse or transformer). Then splice in a 5 foot length of line cord, connecting each lead of the new line cord into the cut. Route this wire to the front of the game. Drill a hole in the bottom of the cabinet, and mount a single-pole, single-throw (SPST) switch. It's not a bad idea to mount the switch in a piece of 3" x 3" x 3/4" thick plywood, and then mount the plywood to the bottom of the game with the switch trigger sticking through the bottom hole. This prevents the trigger of the switch from protruding under the game, where it could get damaged. Connect the two leads to the switch. There is a picture of this further down in the document under Gottlieb Coin Doors.

• Check the coin mech switches in the coin door. This is especially a problem on Williams pinballs. If the switch that detects a coin drop is stuck on, the game won't work.

• Check all the coin door wires. Many games will not even turn on or start if a coin door wire (or the coin door connector) is not attached. This especially applies to Gottlieb and Bally games.

• 1975 and later Gottlieb game won't reset a game properely.
  These games replaced the reset bank with three latched relays called the Ax, Bx, and Cx relays. Located in the backbox, these latched relays have very little switch travel. They must be adjusted perfectly for the game to reset. Also it is very easy to distort the switches in these relays. If the actuator plate is manhanded, it can come off its pivot point. This may cause all the switch blades to come out of their corresponding reset holes. This can cause quite a mess, and the game will never operate till this problem is fixed.

Bridge Rectifier and capacitor on 1972 and later Williams' EM games. Note the two different types of bridges used. They both work the same, they just look different! Bridges you buy today will look like the one on the right. The bridge and the capacitor convert AC voltage to DC.

• The main solenoid fuse blows on 1972 and later Williams EM's and 1976 and later Bally EM's.
  Starting in 1972, Williams changed their pop bumper and slingshot kickers to operate on DC voltage. Bally also made this change in 1976. This made these solenoids a bit more powerful and snappy. To do this, Williams and Bally used a silicon Bridge Rectifier. Unfortunately, sometimes these bridges short internally, and will blow the solenoid fuse when a game is started.

  Replace the bridge with a new 100 volt (or greater), 25amp bridge. For quick analysis, you can buy a 50 volt bridge at Radio Shack if you're in a pinch, but this is barely enough. But it will work. If the fuse blows that is situated right next to the bridge, check all DC components (bumpers, kickers, etc.) for a short.

The reset bank is what starts up a game when the replay (start) button is pushed on the front of the game. If a game won't start, below is some histor on the reset bank, and a list of things to check.

A Gottlieb Reset bank.

Reset Bank.
The Gottlieb Reset Bank was used till 1975 (when it was replaced by the Ax, Bx and Cx latched relays on multi-player games). Super Soccer (1/75) seems to be the last multi-player game with a reset bank. Single players games got rid of the reset bank sooner; Pop-a-Card (3/72) or Space Orbit (4/72) were the last single player games with a reset bank (Grand Slam 7/72 does not have a reset bank). The bank was eliminated largely for cost reasons.

The reset bank is basically a whole row of relays mounted in a metal rack with a master reset bar. When the reset bar is pulled (by its BIG 120 volt solenoid, top right in the picture), all the relays are reset to a known state. This happens at the start of every game.

The Gottlieb reset bank includes several important relays that are crucial to starting a game. This includes the Game Over relay(s), Reset relay, Tilt relay, and the Start relay. Make sure all these relay's switch contacts are clean and adjusted. In order to see any reset bank relay switches, you have to loosen the two wing nuts at each end of the reset bank, and "flip up" the bank.

Unfortunately, flipping up the reset bank is deceptive. When the bank is in operating position, many of the switches rest against the reset bar. But when the bank is flipped up, the reset bar is out of the picture. This can give false switch contact adjustment readings. Just be aware of this.

The Gottlieb reset bank must be positioned correctly, or the bank will bind and not work properely. The rounded edges of the rotating reset bank should line up perfectly with the rounded edges of the locking plate (as shown here with the arrow).

The main Gottlieb reset bank solenoid (the BIG one, upper right corner of the above picture) operates at 120 volts on many games! Also the start relay operates on 120 volts too. Keep this in mind when working on the reset bank. Don't shock yourself.

The Gottlieb "S" Start Relay.
Almost every Gottlieb EM with a reset bank has an "S" start relay. When this relay gets activated (by pressing the coin door start button), the game goes through its start-up sequence. Generally speaking, here is the start-up sequence:

• Press the start button on the coin door. This completes the circuit to the start relay, and causes this relay to pull in and close some switches.
• The score motor starts.
• The score reels reset to zero.
• Any Feature relays or Feature banks reset.
• The reset bank solenoid pulls in, and resets all the relays in the bank.
• The ball is served, and the game can begin.

If you have cleaned and checked all the score reels switches and stepper units, and the game still won't start, check these things:

• There could be no credits on the game; check the credit unit as there is a single switch on that unit which when open, will not allow a game to start.
• On manual ball load games, there is a switch on the ball release hold mechanism. When the ball release coil is energized, this switch opens, and will not allow a new game to be started, until the ball release coil de-energizes (after the first points of the game are scored).
• On Gottlieb games, make sure the coin door is plugged in. The game won't even turn on if the coin door is not plugged in.
• Make sure the hold relay is pulled in, and the switch(es) on the hold relay are working properely.
• Gently rotate the score motor slightly with the game on. Does the score motor advance 120 degrees? Sometimes the score motor can get "stuck" in an "off" position, and manually rotating the score motor can be enough to awaken it (also check the score motor's "home" switch for pitting and mis-adjustment).
• A dirty switch on the "S" (start) relay, or game over relay(s), or reset relay(s).

If there are credits, flip up the reset bank, and clean and check all the switches on the "S" and game over relay(s). While you're at it, clean and check ALL the switches in the reset bank. If the score reels are OK, it's almost a given that your Gottleib game start up problems lie in a switch in the reset bank.

If a Gottlieb game to will not start with the coin door replay button, try manually reseting the reset bank. This will often be the kick that gets a game awake from the dead.

The Gottlieb reset bank with the end wing nuts loosened, and the bank "flipped up". You have to do this to clean any of the switches. Note you can see the nasty start relay EOS switch at the bottom left.

The Gottlieb Armature Activated Start Relay Switch.
Another particularly nasty animal is the Gottlieb armature activated start relay switch. This switch lives under the start relay, and can't be seen unless the reset bank is lifted. Unfortunately, it is difficult to see and adjust this switch unless the reset bank is down. So how do you see and adjust the switch? Well you really can't without unbolting and removing the entire reset bank from the bottom panel! Often this switch is dirty or mis-adjusted. If mis-adjusted, the game won't start properely: the score reels and feature banks will reset, but the start sequence just stops there. So it's a pretty important (and over-looked) switch! The switch is activated by the armature mechanism that trips the start relay. It is labeled on the schematics as the "S Armature" switch.

Gottlieb Single Player Games without a Reset Bank (1972-1978).
Single players games got rid of the reset bank around 1972. Pop-a-Card (3/72) or Space Orbit (4/72) were the last single player games with a reset bank (Grand Slam 7/72 does not have a reset bank). The reset cycle on these 1972 and later non-reset bank games is pretty simple:

• Pressing the coin door replay button (assuming there are credits on the game!) pulls in the start relay (if this does not work, the start relay on the bottom board can be activated manually).
• A switch on the start relay causes the hold relay to pull in and lock on. This turns on the playfield lights and completes part of the power path to the playfield solenoids.
• A switch on the start relay causes the score motor to turn.
• A switch on the start relay and the score motor causes the ball count unit to reset (to position zero).
• If the game has drop targets or a playfield relay bank, a switch on the start relay and the score motor will cause these to reset.
• A switch on the start relay and score motor pulls in the V reset relay (an interlock relay). A switch on the V relay causes the start relay to de-energize (the start relay was energized for just an instant while all the previous steps occur).
• A switch on the V relay and the score motor (which is still turning) causes the score reels to reset to zero.
• As soon as the score reels reset to zero (closing all the score reels zero position switches), the Vr relay pulls in. This releases the V relay (the V relay was locked on for a few seconds as the score reels reset to zero).
• If there is a ball in the outhole (closing the outhole switch), the Ball Return relay pulls in for an instant. A score motor switch and a switch on the Ball Return relay will energize the outhole kicker, and kick the ball from the outhole to the shooter lane.
• The score motor will stop running as soon as the Ball Return relay de-energizes.
• As the ball rolls into the shooter lane, the ball rolls over a switch which closes for an instant. This advances the ball count unit from the zero position to the ball one position. A switch on the ball count unit then closes which turns on solenoid power on the playfield.
• The game is now ready to be played.

The ball count unit is a major player in this reset sequence. When the ball count unit is at the zero or six (game over) position, a switch is opened which does not allow power to any playfield solenoid. So the increment of the ball count unit to ball one turns on all the playfield solenoids. Likewise, the game is over when the ball count unit moves to position six (this again opens a switch and turns off the power to the playfield solenoids, and turns on the "Game Over" backbox light).

If the game resets, but none of the playfield solenoids work, there are two likely culprits. First is the hold relay. There is a playfield solenoid power switch on the hold relay. Second is the ball count unit. If the zero position switch does not close when the ball count unit is advanced to ball one, no power will go to the playfield solenoids.

I'm sure you've noticed by now that there's a motor in the bottom on your EM pinball cabinet with a TON of switches. This is known as the score motor. It's job is to activate relays repeatedly until a feature or job is accomplished. If a job can't be accomplished (for whatever reason), often the score motor won't turn off. It just won't quit till the job at hand is completed!

(Left) Gottlieb score motor. (Right) Williams/Bally style score motor.

Because of this, score motor switches take a lot of abuse. And often need adjustment. As you get experience fixing EM's, you'll probably clean all the score motor switches as a rule. It's a good idea, but don't go wild adjusting them! Particularily on Gottliebs, the switch contact gap distance can be critical in making a game work.

Many beginner EM fixers want to adjust the score motor switches because the score motor won't stop running when a game is attempted. However, the score motor is running because a switch somewhere else is causing this problem! Typically it's a switch that should have opened in the score reels (zero position switch) or in the score relays.

The many levels of switch stacks on a Gottlieb score motor (as viewed from the side).

Getting to those Pesky Score Motor Switch Contacts.
Score motors usually have cotter pins to allow you to release and hinge up the motor, making some switches easier to get at (of course the switch that needs to be adjusted or cleaned will never be one of those switches!). Most have 3 cotter pins to allow you to remove the whole thing away from the frame for better access. They also usually have a disconnect plug to stop the motor from turning. This can be useful in really in-depth troubleshooting; you can try and make the sequence happen slow enough to watch what is happening by using this plug as an on/off switch for the score motor.

Lubricating a Score Motor.
The only part that needs lubricated on Gottlieb score motors is the felt needle bearing pad. This is accessed via a small hole on the bottom of the score motor. Just put a couple of drops of 3-in-1 oil on this pad. No other lubrication is needed! For example, do *not* lubricate the brass gears of the score motor.

Shown here is the bottom of a Gottlieb score motor, and the oiling hole for the needle bearing felt pad. This can be lubricated with a few drops of 3-in-1 oil. Do not lubricate any other parts (especially the exposed brass gears).

The Score Motor's Home Switch.
Check the score motor's "home" switch (on Gottlieb's, usually at 1C or 4C). This switch is what turns off the score motor when it rotates to a "home" position every 120 degrees. Because of the score motor's electro-magnetic field collapse when the motor turns off, the score motor home switch gets a "blue arc" (easy to see when the score motor rotates!) every rotation of the score motor. This blue arc makes the home switch wear and pit easily, and go out of adjustment. If the home switch is out of adjustment or worn, this too can allow the score motor to "over run" a home position, and perhap never stop running!

On Gottlieb games, there is also a "brake" switch. This is easy to identify; it's the score motor switch with no wires attached! It's purpose is to stop the score motor from "over running" a "home" position. If this switch is broken, this can also cause the score motor to over shoot a home position, and to continue running endlessly.

More Score Motor Stuff.
The next section discusses score motors and how they are implemented into the schematics. Scroll down or click here to continue to that section.

Slow and Sluggish Game Motors and Score Motors.
If a game is having a hard time resetting the score reels (they reset slowly), this is usually due to a sluggish or slow score motor. Other game motors (as used in EM arcade games) may be slow and sluggish too. This happens because the grease inside the motor solidifies with time. If this happens, often the motor may need to be taken apart and re-lubricated. Also sometimes the gears inside the motor strip. If this happens new gears will be required (donor motors can be used as parts).

First step is to remove the motor from the game. I can't really give specifics on how to do this, as it is often different from game to game. But the motor will need to removed and isolated from whatever it is driving.

if the motor is sluggish, before "splitting the case", often the gear box can be soaked in alcohol or white vinegar. This can often break down the solidified grease, without take the whole motor apart. The downside is no new lubrication can be added this way. Just let is soak overnight and see if that helps. Sometimes it works, but usually I find myself splitting the motor case anyways for a good cleaning and re-lubrication.

Splitting the Case.
First remove the motor from the gear case. This is not alway possible (depends on the motor), but it is very helpful if it can be done. To get inside the gear case, the case will need to be split. But first remove the motor from the gearbox. This is not always possible (depends on the motor).

The motor has been removed from the gearbox.

The gear case is usually riveted together. Grind the face off one side of the rivets using a Dremel tool, and knock them out with a punch and a hammer.

Here the four rivets have been ground and knocked out.

After the rivets are out, the top half of the case can be removed, exposing the gears. Remove the gears ONE AT A TIME and clean them with alcohol. Be careful, take notes and maybe digital pictures, so the order and position of the gears is documented. Clean the gear case behind the gears too (and of course clean the removed half of the gear case). Re-lubricate the gears with a *light* coating of Radio Shack Teflon Lub Gel.

The top half of the gear case cover has been removed. This motor looks pretty good - not much solidified grease here. But remove each gear, one at a time, and clean it with alcohol.

Re-assemble the gear case. Replace the rivets with some old EM switch stack screws and nuts! These work great and are the perfect size (I believe they are #4 treaded bolts and nut).

The Motor's Brake.
Now check the armature. Many motors have a built-in brake system. This is done so after the power to the motor stops, the motor can not "coast" past a certain switch position. Gottlieb for example uses a switch blade as a brake, mounted on the score motor's frame. But they are the only company I know of that does that. Most other companies (especially Williams) use a spring loaded armature. As power is applied to the motor, the magnetic force pulls the spring loaded armature towards the motor's layered plates. This engages the armature to the gearbox, and the gears turn. As power is turned off to the motor, the spring pull the armature back to the resting position, which disengages the gears. This allows the armature to coast (continue spinning) without turning the gears.

If your motor has this spring loaded armature system, it is *very* important to check that this is working! If the spring is broken, the motor can coast past the position it was intended to stop. This can cause all sorts of problems (like a motor that never stops running, or game features that don't reset properely).

If the armature spring is broken, it can be easily replaced. But don't use too strong of a spring, or the gears may never engage (or not engage fully, causing the armature gear to strip the first gearcase gear). If the spring is too weak, it won't dis-engage the motor from the gearbox. It's all trial and error. I personally keep both a 30 and 50 volt AC transformer on my work bench just for testing motors. This is very handy when having to replace the armature spring, as I can see on the work bench if the armature brake is working correctly.

Starting in the early 1970's, "operation manuals" became available from EM game manufacturers. These manuals outline a "start-up sequence". This is the sequence of events that happens after you press the game's start button. If your EM game doesn't start up properely, this sequence of events can help determine the problem.

The start-up sequence is game specific, but generally can be applied to most games. This is helpful especially on older EM's where there is no operation manual.

The following start-up sequences were outlined from mid-1970's games. They may not apply to the game you're fixing. But they will give you a general idea of what an EM game does when you press the start button.

Bally Start-Up Sequence.

1. Coin is inserted into the game. The coin relay will energize. It will stay energized through its own hold-in switch and a score motor switch. If the credit button is pressed (instead of a coin being inserted) and there are credits, the credit relay will be energized which energizes the coin relay.
2. The coin relay will energize the lock relay (this turns the general illumination on). The lock relay will stay energized through its own hold-in switch and a delay relay switch.
3. The coin relay will energize the reset relay, through a game over relay switch (if your game won't start, try cleaning the contacts on the game over relay; a very common Bally problem).
4. The score motor will operate. This will energize the score reset relay(s). The score reset relay(s) will attempt to clear the score reels to zero. This is done by operating the score motor. Each turn of the score motor will operate the reset relay once, which in turns moves a score reel one position, until the score reel(s) are at zero. If the score motor continues to run when a game is started, there's a good chance the zero position switch on the score reel(s) is dirty or mis-adjusted.
5. The coin relay, through the score motor, will advance the total play meter.
6. The reset relay, through the score motor, will reset the stepper units (zero the ball count and player units).
7. The coin relay, through the score motor, will decrement the credit unit.
8. The coin relay, through the score motor, will energize the game over latch relay coil.
9. The coin relay, through the score motor, will energize the 100,000 relay latch coil(s) (if the game supports scores greater than 99,999).
10. If the outhole switch is closed (single ball games) or the ball trough switches are closed (multi-ball games), a ball is released to the shooter lane through the outhole relay (single ball game) or ball release relay (multi-ball game) and the score motor.
11. On multi-player games, the credit button may be pushed again to add a player. This time the coin relay will not energize the reset relay. Instead it will (through the score motor) advance the total play meter, decrement the credit unit, and advance the coin unit.

1950s Gottlieb Start-Up Sequence.
This applies to single player Gottlieb pin games without score reels (light box scoring), from Triplets (7/50) to Ace High (2/57). These games have no game over relay, and there is power to the playfield at all times (even when the game is over, so a patron can still operate the flippers after a game is finished). Backbox scoring (no score reels) single player games Royal Flush (5/57) to Dancing Dolls (6/60) basically also operate the same, except they have a "game over" relay to kill power to the playfield after the last ball is drained.

1. Insert coin or press the "F.P. Button" coin door start button (if credits are available - the "Zero F.P." switch is closed on the credit unit and score motor switch 1C is closed). Another manual reset method is to reset the Points unit by hand, and then reset the 100,000 unit by hand - this will cause a game reset too (but no credits will be removed).
2. The "S" start relay trips (this is often located on an under playfield bank). This is a 120 volt relay.
3. If the game has trap holes, a switch on the Start "S" relay will energize the Shuffle coil and release the trapped balls.
4. Using the same Start "S" relay switch above, the Points unit will reset to negative one ("-1 pos"), assuming the Points unit is not already at the reset position.
5. Using the same Start "S" relay switch above and a Point unit reset position switch, the 100,000 unit is reset to the negative one ("-1 pos") position, assuming the 100,000 unit is not already at the reset position.
6. Again with the same Start "S" relay switch closed and score motor switch 2C, a credit is subtracted from the credit unit and the mechanical game counter is incremented.
7. With the 100,000 unit at the negative one position, and using a switch on the Start "S" relay and score motor switch 4C, the under playfield bank is reset. This will un-trip the Start "S" relay.
8. With the 100,000 unit still at the negative one position, the score motor turns on.
9. With the Points units at the reset position, the ball release tray solenoid pulls in (dropping the balls to the ball trough for play).
10. The continuous 10,000 unit is reset to the zero position. This is done using a negative one position switch on the 100,000 unit, a switch on the ball release tray solenoid activator arm, and score motor switch 1A (the score motor will not stop until the 10,000 unit is at zero). Note the 10,000 unit relay is not used for reseting the 10,000 unit.
11. The Points and 100,000 units are moved from the negative one to the zero position. This is done using the 100,000 relay (which increments the 100,000 unit) and a Points unit negative one position switch, which increments the Points unit using the 100,000 relay. The 100,000 relay is engerized by the 10,000 unit being in the reset position and a negative one switch on the Points unit, and score motor switch 1A, and a switch on the ball release tray solenoid activator arm.
12. Game is ready to play.
13. As soon as the 10,000 point relay is scored once or twice, the ball release tray solenoid will de-energize allowing drained balls to be trapped.
1954 Gottlieb "Double" Games.
Double games allowed the player to put in an additional coin at the game start to double the number of any replays won. When one coin is inserted, the "thimble" light (on the lower ball arch) is lit, telling the player he can add another coin for a "double" game. This light stays on until the 10,000 unit is moved, turning off the ability for the player to add a coin for a "double" game. If a second coin was added, this will also turn the thimble light out, and the "double" light on the backglass goes on. Note the credit unit on a double game is slightly different than a conventional 1950s Gottlieb woodrail. It has an additional coil and mech that increments the credit unit two credits, instead of just one.

1960s and later Gottlieb Start-Up Sequence.
Games with score reels.

1. 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.
2. The "S" relay will energize the main hold relay to illuminate the game (if this is the first game after power-on).
3. The "S" relay will start the score motor running.
4. The "S" relay and the score motor increment the total play meter.
5. 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.
6. 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.
7. The "SB" relay resets the player unit through the score motor.
8. The "U" relay resets the reset bank (or Ax, Bx, Cx relays on 1975 and later games) through the score motor. It also resets the bonus unit (if the game has one).
9. 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).
10. 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).
11. 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").

Williams Start-Up Sequence.

1. When the start button is pressed, the credit unit is decremented. This is done through the credit unit zero position switch and the 2nd coin relay (and the ball count zero position switch).
2. The end of stroke (EOS) switch on the credit unit decrement coil will energized the coin relay.
3. The coin relay will trip the game over relay.
4. The coin relay will energized the reset relay. The score motor will run.
5. The reset relay will energized the ball count unit reset, through the score motor.
6. The reset relay energizes the 2nd coin relay latch and game over relay latch coils.
7. The reset relay will energize the score reset relays, through the score motor.
8. The score reel reset relays will zero the score reels, through the score motor. The score motor will continue to active the score reset relays until all the score reels reach the zero position.
9. The reset relay activates the bonus unit coil until the bonus unit zero position switch is activated.
10. When the bonus relay drops out, the outhole relay is energized through a different bonus unit zero switch and score motor switch.
11. The outhole relay will run the score motor. The bonus unit will step up once. The ball will be kicked to the shooter lane.

Following these sequences step by step, you can usually generally locate the start up sequence problem. For example, say you have a Gottlieb multi-player game. After pressing the start button, the score motor starts turning, and the score reels all move the zero position. But the score motor keeps spinning and nothing more happens. Looking at the start-up sequence, we can see this would probably be a problem with the "SB" relay and the player unit (or maybe a dirty score reel zero position switch, which occurs in the previous step).

Reading EM schematics is an art. It takes practice. But being able to do it well increases your chance of fixing a game completely. I'll be using Gottlieb schematics for this example. They are the hardest to read (in my opinion). So if you can figure out a Gottlieb EM schematic, you can read any EM schematic!

First, before starting, note there is a BIG difference between a "schematic" and a "wiring diagram". A wiring diagram shows how the wires run through the game. A schematic shows how switches, relays, etc. are connected LOGICALLY to each other. Two parts that are logically connected on a schematic may not have a wire running directly between them! This can be confusing at times when tracing switches.

A Gottlieb schematic showing relay and coil usage.

Relay, Control Bank, Other Coils Matrix.
First lets look at the "relays", "control bank", and "other coils used" matrix on the left side of the Gottlieb schematic. This lists all the relays and solenoids used in a game. It provides some other cryptic information too.

"INDEX" is the index reference. Notice the numbers down the left side of the schematic, and the letter across the top and bottom? These are the index. This makes it (fairly) easy to find where a particular coil or relay is written on a schematic.

"NO." is the letter abbreviation for any coil or relay used. Most Gottlieb relays will have a sticker on them with this letter. This helps you find the coil or relay inside the game. This abbreviation is also used within the schematic itself.

"COIL" is the coil number used for the relay. If you need to order a new relay, this is its part number.

"TYPE" is the type of relay. "INTERLOCK" is a hold relay. "AG" is another style of relay used.

"CONTACTS" tells the number and type of contact switches used on the relay. "4A,1B,2C" means this relay has 4 normally open switches (form A), 1 normally closed switch (form B), and 2 make/break switches (form C). The letters following the numbers are known as "forms". Form A is normally open, Form B is normally closed, and Form C is make/break. The number before the form is the number of this type of switch form used in the relay.

"USE" is the verbal description of the relay.

Schematic Markings.
A Normally Open (NO) switch is two vertical parallel lines on the schematics. A Normally Closed (NC) switch is two vertical parallel lines with a diagonal line across them. A Make/Break switch is a NO and NC switch next to each other with a arrow line pointing to them both. The curly pig tail marking is a coil or relay. A short curly pig tail with a circle around it is a light bulb. Sometimes Williams and Bally uses a circle around a dot to indicate a score motor contact. Other weird markings are usually labeled.

Gottlieb Schematic Markings: most manufacturers use approximately the same marking for their schematics too.

Wire Color.
Another matrix on the EM schematic is wire color. Each manufacturer has their own abbreviations for wire color (to keep it interesting). Check the schematics for this chart. Notice the schematic wires have this label (though some times you have to follow a wire back far through the schematic to its originating point to find the color marking). Some manufacturers use letters for colors, and some use numbers.

Gottlieb uses the "-" and "&" markings between wire colors to mean different things. For example, "BL-WH" means a blue wire with a trace (small) amount of white. But "BL&WH" means a blue and white mottled wire, where each wire is 50% each color.

Bally sometimes uses numbers after their wire color abbreviation. This is the number of times the same wire color has been previously used in the game! This keeps things interesting.

Especially on Gottlieb games, the color red on the wires often fades to white. This makes a white and red wire look all white! This is very common.

When a wire contacts a load (such as a lamp or a solenoid), the wire color will change. Wires that go through connectors should maintain their color(s). The connectors are very seldom shown on the schematics.

Also note wire colors on the schematics can be wrong. It doesn't happen a lot, but it does happen.

Gottlieb's drawing of the Score Motor: it's a VERY deceptive drawing. Note the "side" view is devoid of all switches. The switches bolt to the metal frame with all the holes, and run at right angles to what the diagram seems to imply.

The Schematic's Score Motor.
How Gottlieb refers to the score motor is quite interesting and confusing. They give a diagram which shown the top and side views of the score motor, and labels each level or section.

The top view shows each stack of switches is numbered, one to four. Note the angled switch stack, right next to the "cutout" at postion 3 1/2. This is a point of reference. Most score motors have number stickers on them to avoid confusion, but many times these sticker have fallen off.

The side view shows the level letter of each stack of switches. The level closest to the bottom of the game is "A", and the top most is level "E". For example:

• A = switches below the cam
• B = switches activated with pins below the cam
• C = switches activated by the cam itself
• D = switches activated with pins above the cam
• E = switches activated with TALL pins above the cam

Armed with this info, you can figure out where a schematic switch is located on the score motor. For example, say you are looking for the switch that is labeled "Motor 1C". This would mean you look for the "1" stack of switches, the middle-most "C" level. If you examine this switch stack you might see four switches! Which one is it? This has to be determined by the wire colors, which should also be labeled on the schematics.

This section is a continuation of the previous section entitled, "Reading Schematics".

Often a particular game feature just won't work properely on an EM pinball. These can be frustrating to fix, especially when the rest of the game works perfectly. We will going through an example, and using the same schematics that were pictures in the previous section on "Reading Schematics".

Remember when looking at schematics, that they lay them out with some general electrical path in mind. In Gottlieb's case, this means the left side BLK wire goes to the right side RED-WH wire. Just keep that in mind.

Helpful Hint: Using Feature Lamps to find Schematic Parts.
An easy way to find out what controls a playfield feature is to find the lamp(s) associated with that feature on the schematics. Once the lamp(s) are found, you can trace them backwards to the relay that controls them. For example, say the "special when lit" feature is not working on your game. Find this lamp on the schematic, and trace the wires back to the relay that controls it. Now check and clean the switches on that relay and your problem may be fixed.

Helpful Hint: Using Alligator Jumper Wires.
Another helpful hint is to use those alligator clip jumper wires to bypass elements when trouble shooting. For example, if there are two switches going to a non-working coil, use the alligator clip jumper wires to bypass one switch. If the coil now works, this shows the problem lies somewhere in the bypassed switch area. If there are a number of switches, start "furthest" away, and bypass all the "in-between" switches. If the coil works, move the jumper one switch closer to the coil. Repeat until the coil no longer works. Using this technique the area that has the problem is made smaller, and easier to examine and find the problem.

Gottlieb's "Batter Up" EM Pinball Schematic: this section of the schematic deals with the "Home Run" game feature.

An Example.
Let's say the rollover switch on the playfield for the "Home Run" doesn't work. The switch itself is fine; clean and adjusted properely. But what ever it controls is not working.

Looking at the "RELAY" matrix on the schematic, we can see there is a relay that controls the Home Run feature. It's abbreviated as "H", and is located at index 6E. Going to this part of the schematic, we see a relay coil labeled "H" with a WH-BL wire connecting to it. This is the Home Run relay coil. If you follow the wire to the right, notice it hits the "Home Run Rollover Switch", two normally open switches. These are the playfield mounted switches. The wire then continues down and to the right through "Motor 1C".

At this point you need to check the score motor switch 1C and clean and adjust it. After that is done, test the feature. If it works, you're done. If not, you need to see what other paths exist for this feature.

Notice just to the right of coil "H", the WH-BL wire goes down to a normally open switch labeled "H". This switch is on the H relay. Following it further down it continues to the right and eventually hits a normally closed switch through a WH wire labeled "Motor 2B". I would clean and adjust the WH-BL wire switch on the H relay, and clean and adjust the WH wire switch on the score motor at 2B.

There's yet a third path that the Home Run feature takes: through the Vari-target. So if the feature still doesn't work, I would clean all the contacts on the Vari-target, and the OR-WH switch that goes to relay "U" (vari-target reset relay). After the U relay the wire terminates thru the NC motor 2B switch, which we previously cleaned and adjusted.

Another Example.
Here's another (trickier) example of using schematics. This time, when pressing the start button on a Bally Nip-it, the game would not reset properely. The "ball in play" display on the backglass would stay at ball 3. The stepper unit was recently rebuilt, so there were no mechanical issues. If I manually pressed the ball count unit reset coil, the stepper unit would reset, and the backglass would correctly state the first ball as "ball 1".

Bally's Nip-it: Note the "Ball Count Unit Reset Solenoid", top center.

Looking at the schematic's "Ball Count Unit Reset Solenoid", I could see there were several other things getting reset through the same set of switches. Note the make/break Reset Relay switch, to the left. And just before that, was the Total Play Meter and Coin Unit Step Up coil. And controlling them was a switch on the Score Motor (3A), and a switch on the Coin Relay. Going in the other direction (to the right) effected the Player Unit only, and didn't seem to have anything to do with the reset sequence.

I also noted that when I pressed the start button, the Total Play meter did not advance. This ruled out the make/break switch on the Reset Relay. Only thing left was the score motor switch 3A, and the coil relay switch. I examined both switch and they were clean and adjusted correctly. So what was causing the problem?

If I looked closely at the Ball Count Unit Reset coil, I could see it was trying to reset when the start button was pushed. The pulse to reset this coil just wasn't long enough to pull the coil in and reset the stepper unit. Going back at the coin relay switch, I used a wire with two alligator clips and made the coin relay switch permanently closed. Hitting the start button now allowed the Ball Count Unit Reset coil enough time to reset properely!

Since the coin relay switch was on the Coin Relay, what ever was controlling the Coin Relay wasn't keeping this relay energized long enough. Back to the schematics to look at what controls the Coin Relay!

Bally's Nip-it: Note the "Coin Relay", upper left corner.

The Coin Relay is controlled by two parallel switches: one on the Coin Relay itself, and a switch on the Credit Relay. Then these go to the score motor switches 8F SCM and 10F SCM.

First I looked at the two score motor switches (8F & 10F SCM). These were clean and adjusted properely. Next I checked the switch on the Coin Relay itself. This was a "hold" switch, and was clean and adjusted. That only left the Credit Relay switch. Hitting the start button while watching this switch, I could see the switch arcing. This was the problem! The switch was dirty enough and mis-adjusted enough to not make good contact. Adjusting and cleaning this switch fixed the problem.

• Problem: On a Bally EM, the general illumination (GI) dims during game play.
  Solution: Check the fuse holders. Particularly on Bally games, the fuse holders can lose their tension, causing the fuse to be loose. This can cause dim GI. The only solution on Bally's is usually to replace the fuse holder. Most other brands you can re-tension the fuse holder. In a pinch, you can use an aligator clip over the fuse and fuse holder saddles to keep the fuse in place, and provide proper tension and conductivity to the fuse holder.

• Problem: On a Gottlieb EM, the Pop Bumber relay is stuck on. This in turn causes the score reel to be stuck on.
  Solution: To understand what was wrong, we have to know how the pop bumper works. When the ball on the playfield hits the pop bumper, it closes a switch which in turn, energizes the pop bumper relay. Then the relay does the following by closing it's normally open switches:
  • Closes a switch which keeps the pop bumper relay energized.
  • Energizes the associated score relay (to score the points).
  • Energizes the 00-90 unit (to advance the match and ring a bell), or activates just the bell solenoid.
  • Energizes the pop bumper coil itself to kick the ball.
  When the pop bumper coil itself is energized, the mechanism pulls in the coil plunger on the bumper. At the end of stroke (EOS) of the plunger, there is a normally closed EOS switch. When this switch opens, it interrupts the power to the pop bumper relay, which releases the relay.

  The solution is to clean and check two switches. First, clean and check the pop bumper coil EOS switch. If this fails, the pop bumper relay will forever stay energized because the power to it never gets interrupted. Second, there is a large set of contacts on the pop bumper relay, which controls power to the pop bumper coil. It turns out this contact was dirty and gapped to large. Hence the pop bumper relay would pull in, but not energize the pop bumper coil itself. Since the pop bumper coil never got energized, it never pulled the plunger in and never opened the EOS switch. Without opening the EOS switch, the power was never interrupted to the pop bumper relay. Cleaning and adjusting this switch fixed the problem.

• Problem: On a Gottlieb EM, when a coil is energized, the lights dim on the game.
  Solution: When a coil fires (such as the pop bumpers), this significant power drain can dim the playfield lights slightly. If this happens more than "a little", the cause could be this: the Tilt relay!

  When a game is tilted, the tilt relay pulls in and turns off the power to the playfield lights and solenoids. If the tilt switches do not have good contact or good switch tension, playing the game can cause the tilt switches to open very slightly as the game vibrates. This can cause the game's lights to dim when a pop bumper is activated during play.

  To fix this, make sure all the switches on the tilt relay are clean, and making good contact. Also make sure the switche blades have ample spring tension, keeping their switch contacts tight when the relay is not energized.

• On my Williams Magic City, the ball wouldn't kick out of the outhole strongly. It would usually just roll halfway up, then roll back and be kicked again.

  Solution: What I thought was a problem with the outhole kicker solenoid turned out instead to be a misadjusted switch on the score motor. This mis-adjusted score motor switch caused the solenoid to be activated not long enough to give the ball a good kick.

You have your favorite Gottlieb game up and running (well almost). You're proud of yourself. So you decide to play a game. But you touch the start button on the coin door and ZAP! You get a nice friendly shock!

The fish paper that touches the start (replay) button on this game has shifted over (and may be torn). This allows the metal start button to make direct contact with the switch blades. SHOCKER!

The reason this happens is because the metal start (replay) button is connected directly to the start relay. This relay operated on 115 volts, not 25 volts, like most other relays and coils. Since the start button is metal, Gottlieb puts a fish paper insulator between the button and the switch contacts. This prevents a shock. But with time the fish paper wears, tears, or shifts to the side. This allows the metal start button to touch the switch contacts directly. When you press the button, you become electricity's easiest path to ground. Hence you get a shock.

Another way to get a shock is from the coin door coin switches. Again, at least one of these switches are connected directly to the start relay. If the fish paper that insulates these gets worn, torn or shifts to the side, again you'll get a shock.

Notice the fish paper on this coin door coin switch is ABOVE the lever that trips the switch. This could cause a coin door shock. The fish paper should be between the trip lever and the contact blade, insulating the contact blade from the trip wire (which is metal and touches the metal coin door).

To make sure you don't get a shock, it's a good idea to replace the fish paper on the start button, and to check the fish paper on the coin switches.

Install a new power cord: cut the old power cord out of the game. Wire a new one in (see black wires), and attach the green ground wire to the metal frame of the transformer. Shown here is the brown line cord which goes to a power switch at the front of the game. When done, use nylon wire ties to attach the new power cord to the existing wiring harness (like the old one was attached).

Another good idea is to ground your game. Installing a NEW three prong power cord and plug is a good idea. The original power cord is probably 25+ years old. Run the power cord's ground wire to the metal frame of the power transformer. Then run a wire from the transformer's frame to the back end of the metal side rails. Run another wire from the front end of the side rail to the coin door and lock down bar. Lastly, run a wire from the coin door to the other side rail. While you're at it, it may not be a bad idea to add a power switch to your game too (as discussed previously in the Typically What's Wrong section).

Coils Explained.
A coil's strength is basically determined by three things: the voltage to the coil, the number of turns of wire, and the gauge (thickness) of the wire. Since the voltage usually can not be changed in a game (other than putting the game on "high tap"), only the number of turns and/or wire gauge can be changed. Here's what to remember:

• The higher the voltage feed to the coil, the more powerful it will be.
• The lower the resistance of a coil, the more powerful it will be.*
• The less turns of wire, the lower the resistance, and the more powerful the coil.*
• The thicker the gauge of the wire, the less resistance, and the more powerful the coil.*
• * If coil resistance is too low (about 2 ohms or less), a coil stops having magnetic strength and starts becoming a dead short.

The "less turns of wire, the more powerful it will be" rule is only good up to a point. That is, if the resistance of a coil goes below about 2.0 ohms, it becomes essentially a dead short. This means the coil will not work correctly, and may blow fuses too. Also a coil with too little wire (or shorted wire) can have an inadequate magnetic field.

With this in mind, if at least one lug of the coil is desoldered from its attaching wire, the coil's resistance can be measured using a DMM (Digital Multi-Meter). If the coil is measured with the DMM "in circuit", an accurate reading will not be seen unless one lug of the coil is freed from its connecting wire.

Coils range in resistance from about 2.0 ohms up to 150 ohms (the lowest resistance coil I have ever encountered is on Williams' 1965 Mini Golf, which uses a 21-475, 1.8 ohm coil, but this is the exception not the rule). The higher the resistance, the less powerful the coil will be. But on the other hand, high resistance coils can stay energized for a long time without getting hot and burning! That's why "hold" relays, which stay energized for periods of time, use high resistance coils (usually 30 ohms or higher).

Remember flipper coils are actually two coils in one package. There is a low resistance (usually 3 ohms or so), high power initial flip coil. And there is a high resistance (usually around 125 ohms), low power "hold" coil. The high power side is activated initially, to kick the ball hard. The hold coil is then placed in series with the power coil (using the now open flipper EOS switch) to allow the player to hold the flipper button in, without burning the coil.

So how do coils go 'bad'? If they get hot, the wire's enamel painted insulation will burn, allowing adjacent turns of the wire to short against each other. This can greatly reduce the resistance of the coil, making it unusable. Shorted coil windings (even if the total resistance is not less than 2 ohms) also messes up the magnetic field of the coil too.

I like to keep a list of common coil numbers and their resistance. This way I can check a questionable coil with my ohm meter, compare the coil's ohms it to my list, and determine if the coil is good or bad. Or if the coil is not on my list, if the game uses the same coil else where, I can compare the two coils' resistance.

Here's a coil that is "cooked". Notice the broken wire in the windings. This coil will measure "open" on the DMM.

Coil Numbers.
Coils often have the numbers AE-22-1200-1 or something similar. Here's what this means:
• AE = The coil form size (the size of the coil's frame).
• 22 = The wire guage. The higher the number, the thinner the wire (and more resistive, and less powerful the coil). The lower the number, the thicker the wire (and less resistive, and more powerful the coil).
• 1200 = Number of turns or wraps around of the wire around the coil. The less turns, the less resistance and stronger the coil.
• -1 (optional) = This can denote the style of lugs on the coil, or the type of coil sleeve used in the coil for a particular application.

Some manufactures (mainly Gottlieb), didn't use the the above coil numbering system. Instead they just have a numbering system that don't relate to the coil's wiring (like A-5141 for their flipper coils). In this case, some people have documented the wire gauge, turns, and resistance of these coils.

EM Flipper coils have a slightly different numbering system, since they are actually two coils in one package. These usually have a coil size letter, followed by two pairs of numbers.

The broken wire was reattached on this coil and checked with the DMM. Note the resistance is only 1.0 ohms! This coil is *bad* and must be replaced.

Broken Coils.
Coils can often have the wire winding break from the solder lug. This is often an easy fix. Just unwind a single "wrap" from of the wire (if possible), sand the wire clean to remove the painted enamel insulation, and then resolder the wound wire to the lug. Then test the coil with a DMM to make sure it is not open.

A Low Resistance Coil Problem.
Problem: "The ball release coil on my Gottlieb 1965 Central Park doesn't de-energize, and I see a BIG spark from the switch contacts on the ball release coil and on the one point relay."

The ball release coil is a hold coil. It stays energized until the first ball scores a point. There is a normally closed switch on the one point relay. When a point is scored, this switch opens, and de-energizes the ball release coil.

The key here is the "big spark" on the switches. This signifies that the coil has a resistance that is too low. This happens often on hold coils, which stay energized for a long time. These coils get hot, and burn their insulation from the internal wires with time. This causes an internal coil short, and lowers the coil's resistance. This in turn causes more heat, and more burning, until the coil is a near short (less than 3 ohms). Any hold coil should have a resistance of 12 ohms to 200 ohms. Less than 10 ohms, and the coil will get hot quickly and burn if energized for even short periods of time.

When you get a "big spark" between switches, this mean electricity is arcing between the switch points. This doesn't allow a normally closed switch to really open, and the hold coil never de-energizes. Since the ball release coil's resistance was so low, this made the release switch arc, and never allowed the switch to open (and de-energize the coil).

After the ball release coil was replaced, the excessive switch arcing stopped, and the coil worked as it should (it de-energized when the one point relay was activated).

In case you're wondering, there is no factory setting or adjustment to set your EM to free play. You'll have to cheat to make your game so it doesn't require quarters to play. In order to do this, you'll need to find the credit stepper wheel in the lightbox. Pretty easy to identify: it has a wheel with the credit numbers on it!

Bally credit wheel: adjust one switch permanently closed for free play.

Bally Free Play.
There is only one switch that controls free play on a Bally game. Set the credit wheel to zero credits (shows zero credits through the backglass). On the stepper unit there will be a knotched wheel with a fixed pin sticking out. This pin should have opened a switch only when the credit wheel is at zero credits. Adjust this switch so it is permanently closed (or use a jumper wire), regardless of the credit wheel position. Note there may be a second movable pin (with a slotted head). This is the maximum credits pin. Do not change the switch this pin contacts. Your Bally game is now set on free play.

Williams credit wheel: adjust the top switch permanently closed for free play.

Williams Free Play.
There is one switch that controls free play on a Williams game. Set the credit wheel to zero credits (shows zero credits through the backglass). On the stepper unit there will be a knotched wheel with a pin sticking out. This pin should have opened two switches only when the credit wheel is at zero credits. Adjust the top switch (or use a jumper wire) so it is permanently closed, regardless of the credit wheel position. Note there may be a second movable pin (with a slotted head). This is the maximum credits pin. Do not change the switch this pin contacts. Your Williams game is now set on free play.

Gottlieb credit wheel: adjust the one smaller contact switch closest to the backglass permanently closed for free play. The other switch should be normally closed, but opens at the zero credit position only.

Gottlieb Free Play.
There is one switch that controls free play on a Gottlieb game. Set the credit wheel to zero credits (shows zero credits through the backglass). On the stepper unit there will be a notched wheel with a pin sticking out. This pin should have opened two switches only when the credit wheel is at zero credits. Adjust only the smaller of the two switch contacts (located closest to the backglass) so it's permanently closed (or use a jumper wire), regardless of the credit wheel position. The other switch should operate normally, and be open when the credit wheel is at zero credits. Note there may be another movable pin (with a slotted head). This is the maximum credits pin. Do not change the switch this pin contacts. Your Gottlieb game is now set on free play.

Add-A-Ball Free Play.
In 1960, Gottlieb invented something called "add-a-ball". These games awarded additional balls during a game instead of a free game (known as a replay) when the player achieved a certain score. This was done for legal reasons in states that wouldn't allow a player to actually "win" a free game. Wisconsin and New York were the two big add-a-ball (AAB) states, though other areas had these laws too.

AAB games are pretty easy to identify; they do NOT have a credit wheel! Also the ball in play designation on the backglass is usually labeled "balls to play" instead of "ball in play". Since you couldn't win a free game, there was no need for a credit wheel. Since there is no credit wheel, the procedure to makes an AAB game "free play" is a bit different than a replay game.

Setting free play on an AAB is often easy if a coin door coin switch automatically starts a new game (when a coin is dropped into the coin door), and there is a start button on the game. Just cut and tape off the current wires going to the start button. Then move (or jump) the wires from the coin switch to the start switch.

Note early Gottlieb AAB's don't have a start button on the coin door (remember, no need for one as dropping your money in the coin chute started a game automatically). Often you can bend the coin switch's activator wire lever so it is moved by the coin return button! This is an easy 30 second modification, which can be easily reversed. Starting the game only requires pushing the coin return button on the coin door.

Another exception to this is on late 1970's Gottlieb EM games. These games' coin door coin switches do NOT start a new game. A coin is inserted into the coin door, and the start switch must then be pressed to start a new game. Free play on these games is a bit different. You must "double up" the start switch. That is, make the start switch TWO switches. As the start button is pressed, first it closes two contacts that connect to the coin switch (this simulates dropping a coin in the coin door). Then as the start button is pushed further in, it closes two contacts that actually start the game. These two switches must be insulated from each other with fish paper in the switch stack!

Keeping your EM playfield cleaned and waxed is of major importance in game performance. Dirt on the playfield slows the ball down, and increases playfield wear.

There are a number of products you can use for cleaning the playfield. Millwax comes to mind. Personally, I would avoid this product. Millwax isn't even really a wax. It's a cleaner with extremly small amounts of wax and lots of solvents to keep the cleaner/wax in an easy-to-apply liquid form. It's false protection; you're not waxing your playfield, you're only cleaning it with Millwax. Also Millwax contains petroleum dissolutes, which are probably harmful (and smell bad!). And stay away from all Wildcat products as they crack mylar and yellow plastic parts.

Personally I like Novus#2 for cleaning EM playfields. It works great, and leaves a great shine. It contains no harmful solvents. It's very gentle, yet cleans fast and well. I buy it at my local grocery store, but you can also get it through most pinball retailers.

After cleaning your playfield, apply a good HARD wax. Trewax or Meguires Carnauba Wax work great. Both of these waxes are just that; wax! They have little or no detergents or cleaners in them. Notice how difficult they are to remove and polish after they haze (as applied per the instructions)? This is good! It means your pinball will have a hard time getting them off too. I recommend you re-wax your playfield every 100 games with these waxes.

Also a scratched ball can slow and damage the playfield. Replace the ball if it's not shiny like a mirror. They are only about $1.25 each. Throw the old balls away.

Clean WHITE playfield rubber will keep your game in tip-top shape. Many suppliers sell rubber ring kits; just specify the name of your game, and they'll send you the exact rings for it. And don't forget to get flipper rubber, a new shooter tip, and a rebound rubber.

Do not use black rubber on EM games. It looks bad, is much harder, and hence has different (less!) bounce. Black rubber is designed for the newer, faster Solid State games. Black rubber also creates black dust, so you have to clean the playfield and parts more often.

Clean rubber has amazing bounce properties. Dirty rubber has seriously reduced bounce. The more bounce, the more fun your game will be. If you want to try and clean your old (only slightly dirty) rubber, you can use WAX or Novus2. Trewax or Meguires Carnauba Wax works great on lightly soiled rubber. Just remove the rubber and wax it. Wipe off the excess with a clean rag. The wax will keep your rubber supple and UV protected. You don't even have to remove the rubber if it's not too dirty. For dirtier rubber, try alcohol. Use a clean rag and wipe the rubber down. As a last resort, for really dirty rubber, lacquer thinner works well. But don't get that near your playfield! It will ruin the paint.

Some will call this blasphemy. They'll complain you'll wear out your playfield. You'll break plastics and drop targets. I call it just plain fun: making your EM play fast!

Warning: if you have an EM with drop targets close to the flippers, these upgrades may not be a good idea because of potential breakage (though I've been running them for some time now without any breakages or problems).

Double Warning: Keeping your playfield CLEAN and WAXED is mandatory for these modifications!

(Left) This Williams transformer has two lugs on the right that are normal-tap (24 volts) and high-tap, from left to right. (Right) Bally transformers are a bit more cryptic. High-tap is lug number 2 on the left, and normal-tap is lug number 4. This game is set to high-tap.

High-Tap.
All the manufacturers have a transformer setting for locations with "low line voltage". Low line voltage happens most often in the summer when your game is plugged into a power line that shares an air conditioner.

The high-tap transformer setting will bump up the solenoid voltages (only) about 4 or 5 volts. This gives your pop bumpers, kickers, and flippers a bit of extra power. Don't worry, you won't burn out coils faster with this setting. I set all my EM games to high-tap and it gives them just a bit more punch.

High-tap does NOT effect the lights. High-tap ONLY effects the solenoid voltages. The 6 volts used for the bulbs aren't effected. They use a separate winding on the transformer. (Well, this isn't completely true. If your Gottlieb game has a light feature like "Last Ball In Play", high-tap could roast that particular bulb (only). This happens because some feature lights run off the 30 volt solenoid voltage and use a 35 ohm 10 watt resistor to knock the 30 volts down to 6 volts. If you go to high-tap, you have to double this resistor to 70 ohms. Otherwise that bulb (only) will fry immediately. These lamps can be easily seen on Gottlieb schematics. All the normal 6 volt lamps will be on the upper left corner. If a lamp is shown on the shematics in the same section as coils and relays, then there will be a drop-down resistor to limit its lamp voltage.)

This Gottlieb transformer has two lugs on the left that are the high-tap and normal-tap, from left to right. This game is set to high-tap.

High-Power Flipper Coils.
Steve Young at Pinball Resource (see the parts and repair sources web page) sells high-powered flipper coils for Gottlieb and Bally games. They are about 20% more powerful than the originals. I like these a lot, especially in small flipper Gottlieb games. Some people will argue that you could damage a plastic or drop target. But i've been running these without problem for some time now. On small flipper games, they are mandatory for me. But I like them on long flipper games too. I use these and hi-tap together. Note high-power flipper coils give the game a different feel.

If you have a Williams EM, I wouldn't change the flipper strength. These games (especially the DC powered games) are already pretty strong.

On Bally games, the general coil for small flippers (including zipper flippers) is AF25-600/31-1000. This is the same power winding as the coils used on Wizard and other similar games, which is AF25-600/28-800. The next step stronger is the coil used for games like Captain Fantastic, coil# AF25-500/28-1000. So for zipper flipper games, Wizard, etc, I would recommend that as the upgrade. For those concerned about breaking zipper flipper parts with hotter coils, Pinball Resource (see the parts and repair sources web page) now sells zipper flipper rebuild parts. This includes old style and flipper zipper bushings, #C649 ($2.79), the lever arm #A1889-7 (right) and #A1889-8 (left, $10.71). It's a good idea to replace these parts when adding the stronger coils, especially since the original hardware is probably worn to begin with. If using stock zipper flipper coils, be sure to change their metal coil sleeves to new nylon sleeves.

New Flipper Links and Plungers.
Flipper links are a fiber material that connects the flipper plunger to the flipper pawl. With time, these wear and the attachment holes enlongate. This puts play in the mechanism, which absorbs some power from the flipper. The result is less than powerful flippers.

Buying new flipper links solves this problem. While you're at it, you might as well get new plungers too. After 25 years or more of use, often they get indentations worn in their sides.

Also make sure the flipper return spring isn't wound too tight. This can cause additional resistance to the flipper, and make it weaker. Adjust the spring so it has just enough power to return the flipper.

New Coil Sleeves.
Replacing the coil sleeves on all major coils has a big impact on snappy game play. If you didn't replace the flipper coils (which comes with new sleeves), definately replace the flipper sleeves. It makes an amazing difference in flipper power. Also replace the coil sleeves on the pop bumpers and slingshots. Your game will have much more snap. Don't go too nuts and replace every coil sleeve. Just replace the flipper, pop bumper and slingshot coil sleeves. If your game has metal coil sleeves, these definately need replacement to new nylon sleeves.

Playfield Angle.
If you do the above modifications, you can set your playfield angle fairly steep. I remove the front leg levelers, and set the rear 2" long levelers up all the way. If your playfield is cleaned and waxed, the game plays fast and fun. Maybe this isn't originally how game play was designed, but I like it.

If you find the flippers too weak, you may have to decrease the playfield angle. But if you rebuilt the flippers with a new fiber link, plunger and coil sleeve, this shouldn't be a problem.