EM Repair

1 Introduction

Put system info here

2 Safety

Pinball machines operate off line voltage (120V in U.S.) so care must be taken when working on your machine. If you are not comfortable with the risk you should only attempt repairs that can be done with the machine unplugged.

Most EM machines primarily operate with 6.3VAC and 25VAC, which is somewhat safe. However, line voltage will be present from the line-in cord to the primary side of the transformer and the service outlet. Also, some machines have coils which operate on 120VAC, so some relay switches, score motor switches, and anti-cheat / kick of switches have 120VAC present on them. Finally, some older machines have 120VAC going to the start switch and the weighted slam switch located on the coin door. On these games you should check to make sure the fish paper insulation is still in good condition. The fish paper is used to isolate switch voltages from other current conducting items, like the coin door. If the fish paper is torn, misaligned, or missing, there is the potential to receive a shock. This shock can occur while either playing the game, or by touching the suspect game and another, properly grounded game simultaneously.

By all means if you decide to work on a game, do not perform any repairs in socks or bare feet. Don't laugh people have done and do this.

3 Games

The "Big Three" manufacturers were Gottlieb, Williams, and Bally. The "best of the rest" would probably include Chicago Coin and Midway, as well as some popular foreign brands, such as Sonic, Segasa, Recel, Rally, Zaccaria, and Playmatic. Some of the foreign manufacturers used American pinball manufacturer parts in part or in whole. For example, Sonic is mainly based on Williams EM architecture, while Recel is mainly based on Gottlieb.

A quick search of the Internet Pinball Database, shows that between all the manufacturers, there are over 3403 electro-mechanical games within this very broad category. There were many companies which only produced a few games, especially early on.

4 Technical Info

4.1 The Start Up Sequence Explained

Regardless of a particular machine's manufacturer, every EM pinball machine has a start up sequence. When a coin is inserted, if the coin switch is set for one game per coin denomination, or a credit button pushed, an EM pinball machine has to successfully complete the start up sequence, before a game can properly begin. Analogous to an EM's start up sequence is a computer booting up, and loading an operating system successfully.

The primary events which occur during the start up sequence are:

1. Resetting all the score reels to zero, or resetting lamp scoring values or projected scoring values to zero on machines manufactured prior to the use of score reels.
2. Resetting the ball count to ball 1 player 1 on multi-player games; resetting the ball count to 1 on single player games, where the ball count unit increments throughout a game; or setting the ball count to the maximum balls allowed per game on games where the ball count unit decrements throughout a game. In the case of older machines where a manual ball lift assembly was used, releasing the ball in multi-player games or balls in single player games.
3. Resetting game progressive sequences and features for machines which do not have game-to-game, progressive, carry over game features / sequences.
4. Resetting game specific mechanical assemblies such as single drop targets, drop target banks, vari-target, ball lane gates, etc.
5. Allowing power to pass to the playfield mechanisms

Although some of the above events may not occur, but a game will successfully start and play. These types of issues can usually be overcome rather easily. The more difficult problems are when a particular event or events do not occur or halt the process during start up, and the score motor continues to run. It is up to the repair tech to determine at what point the start up sequence has stalled or failed.

Below are some game specific start up sequences. These start up sequences can be applied to similar machines from the same manufacturer and era. In most cases, the start up sequence is explained in the machine's manual, if a manual was created for it.

4.2 Start Up Sequences

The following is the start-up sequence for a Gottlieb Southern Belle. The Southern Belle is a woodrail from 1955 with lightbox scoring. In other words, it has no score reels. Other Gottlieb woodrails from this era will be similar, but not exactly the same. You will need to consult your schematic and figure out the exact sequence if it differs slightly from the one below:

Southern Belle Start Sequence:

1. Push start button, pulls in start S relay

2. Start relay resets 100K unit, closing switch at -1 position on 100K unit

3. Closed switch at -1 position pulls in Z relay

4. Z relay pulls in ball release coil which is held on by 2 ball hole switches and a switch on the ball release unit

5. The balls move off the two switches, opening the two switches, so now the ball release coil is retained by Z only.

6. Switch on Z relay closes and allows pulsing of 10K unit through Motor 1A

7. 10 K unit continues to pulse until it hits position 9 or 19 or 29 on the 10K unit, then the "bridge" there, in series with the NO switch (which closes once/pulse) on the 10 K unit pulls in the M relay.

8. The M relay steps the 100K drive coil up and stays pulled in until the 100K NC switch is opened (upon stepping once)

9. The 100K step moves the 100K stepper off the -1 position, opening the switch on that keeps the Z relay pulled in.

10. The Z relay releases – the 10K unit can no longer be pulsed though the switch on the Z relay.

11. Z relay opening also releasing the ball release coil.

12. The N flip/flop switch seems somewhat redundant in this setup.

The following is the start-up sequence for a Gottlieb Roto Pool from 1958. You can see it is similar, but not exactly the same as the Southern Belle sequence.

Roto Pool Start Sequence:

1. Push start button, pulls in start S relay

2. Start relay resets 100K unit, through NC switch on motor 1C closing switch at -1 position on 100K unit

3. Closed switch at -1 position pulls in U relay

4. U relay pulls in ball release coil, which remains on by the U relay, a switch on the unit itself and a flip/flop on the N relay

5. Switch on the U relay is closed, allowing pulsing of the 10K unit though switch on motor 1A

6. 10 K unit continues to pulse until it hits position 9 or 19 or 29 on the 10K unit, then the "bridge" there, in series with the NO switch (which closes once/pulse) on the 10K unit pulls in the 0-9 coil relay

7. The M relay pulls in and is held in by it's own switch and a NC switch on the 10K unit and remains on until the 10K unit steps. The 100K step moves the 100K stepper off the -1 position, opening the switch on that keeps the U relay pulled in.

8. The U relay releases – the 10K unit can no longer be pulsed though the switch on the U relay.

9. The N flip/flop switch activates at some point, releasing the ball release coil (IMO, this is a poor design, leading to a burnt coil for any number of reasons (no FMEAs at Gottlieb?)

1960s Gottlieb Add-A-Ball Start-Up Sequence (Flipper Clown)

1. COIN CHUTE energizes START (S) relay. If HOLD (R) relay is not energized it will energize and hold on through it's own switch.
2. S relay switch starts the SCORE MOTOR
3. Score reels reset through S switch and SCORE MOTOR 1A
4. RELAY BANK resets through S and SCORE MOTOR switches 2C and 1B
5. BALLS TO PLAY steps down (SUBTRACT coil) through switches on S and D and SCORE MOTOR 1A.
6. RESET (D) relay energizes when all score reels and BALLS TO PLAY unit are at zero. It holds through a switch on itself for one score motor cycle, dropping out at SCORE MOTOR 1C.
7. While D is energized the BALLS TO PLAY unit steps up five times through a switch on D and SCORE MOTOR 1A.

Gottlieb Start-up Sequences from the 1970s

There is a great repository of Gottlieb startup sequences gleaned from numerous game manuals.

70s Williams Start Up Sequence (4 player)

1. When the start (credit) button is pressed, the credit unit is decremented. This is done through the CREDIT UNIT zero position switch and a set of parallel switches that ensure the game is in "game over" or still on player 1, ball 1, and not at the maximum number of players (COIN UNIT last position switch).
2. The end of stroke (EOS) switch on the CREDIT UNIT decrement coil energizes the COIN relay.
3. The COIN relay:
   • Trips the GAME OVER latch/trip relay once the PLAYER UNIT and BALL COUNT unit reach zero.
   • Energizes the RESET relay.
   • Runs the SCORE MOTOR.
4. The RESET relay:
   • Energizes the BALL COUNT unit reset through the SCORE MOTOR.
   • Energizes the GAME OVER relay latch coil.
   • Energizes the COIN UNIT reset coil.
   • Energizes the NO.1 and NO.2 (score) RESET relays, through the score motor.
   • Runs the SCORE MOTOR.
5. The score reset relays pulse and zero the score reels, through a switch on the score reel that opens in the zero position to stop the reset for that reel.
6. The SCORE MOTOR runs until all score reels and the BONUS UNIT reach the zero position.
7. The RESET relay decrements the BONUS UNIT until it reaches the zero position.
8. When the BONUS RELAY drops out it energizes the OUTHOLE relay through a different BONUS UNIT zero switch and through the SCORE MOTOR.
9. The OUTHOLE relay:
   • Runs the SCORE MOTOR and increments the BONUS UNIT once.
   • Energizes the BALL RELEASE coil which kicks the ball into the shooter lane.

Bally start sequence:

1. When the coin is inserted into the game the coin relay energizes. It stays energized through its own hold on switch and a score motor switch. Once the start button is pressed the credit relay is energized which in turn energizes the coin relay if there are sufficient credits.

2. The lock relay is then energized by the coin relay at which time the game illuminates. The lock relay stays energized through its own hold on switch and a delay relay switch.

3. The coin relay then energizes the reset relay through a switch on the game over relay.

4. As the score motor runs, it energizes any score reset relays. The score reset relay will now resets the score reels to zero.

5. The total play meter is advanced by the coin relay via the score motor.

6. The ball count and player units are then reset by the reset relay via the score motor.

7. The credit unit is stepped down by the coin relay via the score motor.

8. The game over relay latch coil is now energized by the coin relay via the score motor.

9. The 100,000 relay latch coil (if equipped) is energized by the coin relay via the score motor.

10. The ball is now introduced into the shooter lane by the outhole relay via the score motor (assuming the outhole switch is closed).

11. If multiple players are added by the start button, the coin relay advances the coin unit,advances the total play meter, and steps down the credit unit.

4.4 Schematics

A guide to reading schematics is available here: http://tuukan.fliput.net/emkytkis_en.html

5 Problems and Fixes

5.1 Lubrication

Over-lubrication causes far more trouble in coin operated equipment than under lubrication. Practically all cases of poor contact on switches and wiper disks are due to oil or grease, or oil vapor, which forms a film or residue on the contacts and will not allow current to pass through. Excess lubricant may also seep into clutches causing them to slip.

IMPORTANT: NEVER USE VASELINE FOR LUBRICATION OF ANY PART OF THE MACHINE! Vaseline is not a true lubricant. It leaves a dirty and gummy residue and becomes very thick when cold.

Step-up levers, ratchets, cams, shafts and other sliding or oscillating parts should be very lightly greased with special coin machine lubricant. The bakelite disks (biscuits) on the motor units and step-up units will require lubrication with the special coin machine lubricant only after the grease is completely evaporated or when the film of the grease becomes dirty (machines with bakelite disks only). In either event, clean the parts thoroughly with a solvent, then apply an extremely thin coat of the special grease.

Solenoid plungers should not have a lubricant of any kind. Should there be a sluggish tendency or if plungers are sticking, the parts should be cleaned with a solvent and flaked graphite if anything, applied on reassembly.

The general rule is "when in doubt, don't". There are very few places on a pinball machine that need lubrication and they're only in spots that have metal-to-metal contact. When needed, a good choice is "Super Lube Teflon Grease", a clear synthetic grease with Teflon. It can be found at local hardware stores or online, for example: http://www.pinrestore.com/Supplies.html

5.2 Switches

Leaf switches in pinball games come in 4 formats: Normally Open (N.O.), Normally Closed (N.C.), Break-Make, & Make-Make, the last 2 of which are really combinations of a N.O. and/or a N.C. switch. Regardless of their function, all switches are in fact, a N.O. or N.C. type.

Leaf switches in EM games are of 2 compositions,at least 2 bronze blades each holding a Silver Contact or a Tungsten Contact(occasionally 2 contacts per blade). Since silver is a very high conductor of electricity, it is used on most EM switches, with the exception of the flipper cabinet and End of Stroke (EOS) contacts, which are tungsten. Silver tarnishes and turns black, but this does not effect its conductivity. Silver contacts may be cleaned with a flex-file or sandpaper, in order to redress the switch for adequate surface contact. Tungsten flipper contacts must be redressed with an ignition-type flat file as used in automotive repair, as the contacts are too hard to be smoothed by sandpaper or flex file abrasive. Gold flashed contacts, are not normally used in EM games, and must NEVER be cleaned with a file or sandpaper. A business card, or thin cardboard, is all that is necessary to clean electronic gold flashed contacts.

5.2.1 Normally Open (N.O.) Switch aka Form A Switch

Normally Open Switch in resting state

Schematic symbols for a N.O. & N.C. switch

N.O. switch called Closed When Energized (C.W.E) or Closed When In (C.W.I.) on Old Williams schematics c. 1950

This is a leaf switch that has 2 (rarely 4) contacts that complete a circuit when pushed closed by some mechanical device. The switch re-opens when the device moves away from the moveable contact, and the springiness of the blade opens the circuit. Gottlieb calls this type of switch, a “Form A” switch, and this term is sometimes used in its schematics.

5.2.2 Normally Closed (N.C.) aka Form B Switch

Normally Closed (N.C.) switch in resting state with optional nylon spacer

Normally Open & Closed switches on Bally Schematics, c. 1961.If you rotate the line segment representing the pole counter(anti-)-clockwise (CCW), it will have to go almost all the way around to touch the other wire, denoting a N.O.switch. A short CCW rotation signifies a N.C. switch

This type of switch, called a “Form B” switch by Gottlieb, opens a circuit when a mechanical device pushes against the blade. A typical use of a N.C. switch is the bottom cabinet tilt or game off switch GTB uses on early EM games. When the bottom of the cabinet is struck intentionally or by a disgruntled player, the weight on the end of the blade moves the contacts apart and turns the game off.

5.2.3 Break-Make aka Form C switch

Break-Make switch aka Form C in resting state

Schematic diagram of a Break-Make Switch

This switch is really a composite of a N.O. and a N.C. switch with just three blades instead of four. The moveable center blade has contacts on BOTH sides. Proper adjustment insures that when a device moves the center blade towards the open contact, the CLOSED switch OPENS BEFORE the center contact touches the open switch’s contact. When the pressure is released, the center blade returns to its N.C. side and re-makes contact. This type of switch is often used on relays. A Make-Break switch is really the same, just upside-down, or in reverse, of the order of actions of a Break-Make switch. Special care should be taken with a Make-Break switch that the three blades are at not time shorted together. This can happen often when the blade stiffener is maladjusted, and contacts the other blade of the pair.

5.2.4 Make-Make aka Form AA switch

Make-Make switch aka Form AA in resting state

Make-Make schematic diagram

A make-make switch is a composite switch consisting of two N.O. switches using only 3 blades. When mechanical pressure is applied to the blade, the switch “makes” or closes the circuit, and continues to move until a second switch contact is closed, tying all 3 blades together.

Additional information & photos about leaf switches can be found here.

5.2.5 Adjusting Switch Gaps

Useful tools for EM switches. 1) Ignition file for Tungsten contacts, 2) Flexstone File for Silver contacts, 3) Switch adjustment tool, 4) Homemade adjustment tool, 5 )Spring push/pull tool, very useful for switches also.

Proper switch clearance gaps are crucial for correct operation of any pinball game. Very many problems in EM games come down to a problem with incorrect operation of a switch. The switch blades are made up of phosphor bronze, which has high conductivity, resilience to form and excellent soldering characteristics, but has the drawback of being brittle compared to copper. Switch blades therefore, are commonly broken by the game, or careless actions by the repair person. A switch adjusting tool, purchased or homemade, is a necessity. Pliers or screwdrivers might be used in special circumstances, or in extremis, but are not best practice.

Switches in EM games are designed to have a degree of over-travel, which creates a wiping motion that helps clean the switch. The contacts must meet, stay together and slide across the face of the contact slightly, to be perfectly adjusted. They also must be gapped wide enough that they do not bounce, causing multiple switch closures. This problem is more often seen in electronic games, due to the rapid nature of the switch closures being too fast to effect an EM game. Electrical sparking can often be seen in dim light between the contacts, and this is not necessarily a cause for concern.

Before adjusting switches, make certain the screws holding the switch stacks are down tightly. Bakelite spacers in the switch stacks, due to excessive moisture, have occasionally shrunk by drying out, causing poor adjustment. After tightening a switch stack, be sure to recheck the gap of each switch.

If you clean a set of points, and find yourself having to do it again soon. Check the rivet on the point blade. They can come loose and arc and prevent good contact with the blade. Easy to repeen it, or even solder it down. Clean it and you'll be good to go. LTG :)

To adjust a leaf switch, first make sure the switch stack of bakelite spacers and blades are tightly packed against each other by giving the 2 screws a twist of your screwdriver. As long as there is no screw movement with reasonable pressure, you can procede. Some switches have a regular nut on the backside instead of a speednut, which will require holding it as you turn.

Using your switch adjusting tool, put twisting pressure on the moveable switch blade as close to the switch stack as possible, and include the blade stiffener(if present) in the adjuster slot. Try to use as little force and change of gap as possible, and incrementally reach your gap goal. Using too much force and a back and forth gap readjustment, tends to bend and weaken the switch blade, and can make a deformed switch blade difficult to set for correct operation. This is often seen in games that have been “hacked”, and sometimes the only way to remedy the situation is to replace the entire switch, or disassemble it entirely. Cycle and recycle the mechanical device that activates the switch and observe the switch for proper gap, wiping action and release.

5.2.6 Recommended Gap Specifications

Gottlieb recommends a gap of .019" on a normally open switch on the AG relay, with overtravel of .015". The lock-in switch should have only .010 gap in a de-energized state. Absolute precision in these measurements is not critical, but should give you an idea of what amount of gap you should look for. A automotive feeler gauge set could be used to help with this setting, but after some experience, “eyeballing” it will suffice.

Magnet type and interlock relays have longer switch blades, so the gap is wider at .031" or 1/32" with a similar overtravel. Rollover switches that are N.O. have some tolerance to their gap at .031" to .062" or 1/32" to 1/16" with a very small overtravel of 1/64". If the rollover is N.C., only a 1/64" gap is necessary.

Kicking rubber, or slingshot switches usually have a generous gap, at least 1/16", due to the rubber ring pushing back against the switch, and a bit of trial and error will be necessary to find the ideal gap setting. Pop bumper switches and scoring “dead” bumper switches, should have a gap of 1/64" for the actuating switch under the spoon, and a 1/32" gap for the score switch when open. All other types of switches will probably function well with a 1/32" gap, and this would be a starting point, modifying the gap on a case by case basis.

5.2.7 How to Fabricate Leaf Switches

1) Replacement switch blade with pre-formed contact holes 2) Fish paper 3) Blade stiffener 4) Bakelite switch separators in 1/16" & 1/32" thickness 5) Tungsten and Gold flashed contacts 6) Separator and screw insulators 7) “Dead” lug used on SS games

Very often the need to rebuild or fabricate leaf blade switches presents itself to the EM repair person. Sometimes the silver contact is worn out or missing, or the blade is bent or broken, to the point that a satisfactory repair cannot be done without replacing the switch. It can happen that the switch is missing entirely. When doing a repair on location, the exact parts may not be available. Fortunately, most switches for EM games can be replicated, and at a cost that may be cheaper than a new assembly. The mechanical procedure is described below, but first a general discussion of individual components (which I hope will be helpful to the novice) will ensue.

Switch blades come in 3 thicknesses depending on the intended use. The light gauge .008" blade may be used in relay banks where a small coil may have to draw down several switches, and perhaps in a spinner switch. The medium gauge .010 blade is used generally throughout the pinball game for any switch that is not a relay or flipper cabinet or EOS switch. The heaviest gauge .016" is used in EOS and flipper cabinet switches. They can be purchased from PBR, and it is advised to buy several of the medium and a few of the light & heavy blades for emergency and general repairs. These blades are of a single length, which may be cut to a suitable size, and are pre-drilled with 7 contact positions.

Switch blades are brittle, and cannot be bent or formed apreciably without cracking or breaking the blade. This makes it easy to score the blade with some side cutter pliers, then break off the unneeded section by bending it back and forth with a pair of pliers and a vise or some other hold down method. If a formed bend as used in drop target switches is required, an old blade from a scavenged switch must be utilized, or special ordered from a supplier (if available).

New switch contacts are no longer available in silver (that I am aware), but a gold flashed pair of contacts can substitute wherever the voltage and current handling is low. Tungsten contacts must be used for the End-of-stroke (EOS) switches and the flipper cabinet blades due to the higher voltage (35v or greater) and greater current these contacts must supply.

Fish paper spacers may be required for some EOS switches and usually for the coin door credit switch, and perhaps in other instances. The old fish paper if undamaged, can be used, and new pre-cut fish paper blades are available. A substitute can also be hand cut, if the need arises. Next, some switches require a blade lifter or spacer to push upon another switch or mechanism, such as in double EOS switch assemblies and score motor stacks. Many times these can be scavanged from the old blade, or a new one of a suitable length can be used. The height ranges from 3/32" to 11/32" by increments of 1/32", but usually the exact height is not critical. Again, having a small variety of blade lifters on hand for spares, is strongly urged. Some switch assemblies use a metal cover plate and a rectangular speed nut for the anchor for the screws, and new ones are available, but the old ones are usually fine.

Switch stack separators, usually made of bakelite or some other non-conducting material, come in 2 thicknesses, 1/16" & 1/32" and will be combined in various combinations to achieve the desired spacing the operating mechanism required. Old ones are fine to use, but are very brittle and prone to breaking if levered off too strongly or at an angle. A little care in separating the old switch stacks is indicated here. You may purchase new copies from the usual suppliers if necessary, or just scavange the necessary bits from previous repairs or your parts bin. If a machine screw is used to hold the switch assembly in place, it is a 4-40 screw (varying lengths) and corresponding nut, or a #4 pan head screw, if secured to the cabinet or playfield, or by a speednut.<br=clear all>

5.2.8 Procedure to Fabricate a Leaf Switch

If the original switch is present, it is an easy task to replicate a new one, or renew the bad parts, using the old switch as a model. Experimentation will be the only source for a missing or incorrect switch. For a complicated, multi bladed assembly, it is advised to take careful notes of how many spacers were used between each pair of switches,the presence of a "dead" lug (if any) and its location, and which blade had the blade lifter or blade stiffener, etc. Use a Stanley or other utility knife to separate the switch stack, levering each end of the stack a 1/64" or so, taking care not to crack the fragile bakelite spacer. You may also have success using a pin punch to press the tubing out. The tube switch insulators can be re-used or new ones put to service.
Each contact must be peened to the blade tightly for good electrical conductivity. A craftsman may also solder the peened nub to the blade to ensure its faultless operation. Use a hard wood scrap block (maple or similar), to back up the contact, while striking the nub with a punch and hammer. Don't backup the contact with a metal surface like a vise or anvil, as it will likely be marred or cracked. Clip off the long end of the blade if it is too long for the application by scoring the blade with a pair of side cutter pliers, and then bending it back and forth along the score line with suitable means. A bit of attention with a metal file to the ensuing sharp edge may save you a nasty scratch at some point. As an alternative, use a pair of diagonal cutters you don't really care about and just snap right through the blade directly. The nylon blade lifter, if required, may be peened by squeezing it with pliers, since it is rather soft. Re-assembly is straightforward, esp. if you took good notes.

A good substitute for an EOS switch

A useful sub for most low voltage switches

In place of re-creating the entire switch assembly, it may be that the only thing necessary to do is adapt an existing switch to an unavailable assembly by a slight modification of an existing readily available part. The blades are soft and easily drilled for a new spacer or contact, so I have found that an EOS switch like the Williams #03-7811, works quite well with a bit of modification for other EOS switch applications that are unavailable, involve double switches, or are just expensive. If a longer blade is needed, the top blade can be swapped out, or a second switch pair can be sandwiched in for a double flipper setup. Likewise, the Williams/Bally #SW-1A-120 assembly can sub for many playfield applications with just an addition of a spacer or two or a blade lifter. Your ingenuity can compensate for a lack of parts from available sources.

5.3 Coils

5.3.1 Gottlieb Solenoid Coil & Sleeve Chart

Coil	Sleeve	Length
A-1496	A-5065	1 7/8"
A-4893	A-5064	1 21/32" (note B)
A-5141	A-5064	1 21/32" (note B)
A-5143	A-5142	2 3/4" w/collar*
A-5193	A-5171	1 19/32" (note B)
A-5194	A-5064	1 21/32" (note B)
A-5195	A-5064	1 21/32" (note B)
A-5196	A-5172	2 ½"
A-5197	A-5172	2 ½"
A-7800	A-5172	2 ½"
A-9154	A-8111	1 1/4"
A-9479	A-5172	2 ½"
????	A-6087	1 1/4" w/collar*

Where noted with an asterisk*, sleeve has a collar 1/4" from end.

Note B: Original GTB specs are 1 19/32" & 1 21/32" but SUBSTITUTE 1 5/8" instead. Also, SUBSTITUTE 2" for 1 31/32" w/sleeve.

Older Gottlieb and Williams, et al; may use a brass sleeve. If it can be removed, a nylon one can be used, but some brass sleeves are still available.

Additional information on Gottlieb coils & sleeves can be found here.

5.4 Relays

Relays are small coils that when energized complete one or more circuits. They are usually high resistance so they can be activated for a long time without burning up or blowing a fuse. They are the workhorse of the EM world; without the relay, the proper circuits do not get energized and nothing happens. The relays set up the conditions that the score motor then completes the work on.

For example, a 500 point relay will pull in, causing a circuit path to the 100 point relay (which adds 100 points directly to the active score reel set) to be made, and also starting the score motor. The score motor will turn and additional switches will pulse 5 times, causing the 100 point relay to pulse 5 times, adding 500 points to the score. A 5000 point relay operates the same way - except it's completing a circuit to the 1000 point relay. The same 5 pulses from the score motor "do the work" of adding the score.

It is the interconnection of relays and their circuits that comprise the "programming" of an electro-mechanical machine. You can change the way a game plays by adding and changing circuits, to either fix errors in the original programming, or to create new and exciting rules.

5.5 Stepper Units

There are 3 basic types of steppers used in EM machines. These are the step up/reset, the step up/step down and the continuous steppers. The step up/reset stepper is generally used when you only need to count up, not down. An example of the might be on a ball count unit that is used on a replay machine. For this application, you count up to 3 or 5 balls played, depending on the setting, then reset to 0 or 1 ball as part of the start up sequence. Step up/reset steppers are also used for the 100K unit on a Gottlieb Woodrail. They are also occasionally used for bonus counters with the "scan style" bonus used on some later Gottliebs, like Target Alpha or Hot Shot and certainly in other places as well.

A step up/step down stepper is possibly a little more common than the step up/reset style. A typical application would be as the ball count unit on an Add-A-Ball game. Here, it would step up the ball count to 5 (or 3), then step down one at a time as balls are used and step up one at a time as balls are earned. Anther, probably more common application is to count bonus points, where it would be to step up as bonus points are earned, and then step down at the end of the ball, or whenever the bonus is collected. Probably the most common application of all is to count the credits on a machine.

By far the most common stepper is the continuous stepper. They come large and small. The small unit is the infamous, often cursed and never loved AS stepper on later Gottliebs. This is used most often for the match feature and occasionally as part of the circuit for spinner scoring. The AS unit can often be removed from the game by unplugging a pair of Jones plugs. In theory this was done so that the AS match unit could be removed from areas where matches for free games were not allowed. As a practical matter, it is probably a good thing as these miserable little rube goldbergian contraptions will cause you grief at some point and will need to be rebuilt, preferably in a good light. Good lighting is required because when the AS relay malfunctions and needs to be rebuilt, it will get its last lick in by flinging a part of itself across the floor in a desperate suicidal mission to permanently bring your game down.

Luckily, full size continuous steppers are much more common than their diminutive and cantankerous smaller brothers. The full size stepper are often found in the match feature of earlier Gottlieb and Williams games, often ringing the bell while also stepping along merrily with the smallest score increment (1 or 10 points). They are also used in Gottlieb woodrails to track the 10K points and send a signal over to the 100K stepper when it steps past 90K and needs to carry the decade over. Another common application is in the "player unit" on multi-player Gottliebs. By far the most common use of the continuous stepper is in the score reels. In fact, it is so common that score reel rebuilding was given its own section in the Pinwiki. A continuous stepper often is used very heavily, which means they are subject to wear out – possibly more than other failure modes such as getting gunked up.

One thing that all steppers have in common is that then need to work well for you to be happy with the way your game functions. In fact, most of the functions are so integral to the game that your game will be "broken" if the steppers do not work. Most games cannot get through a reset sequence unless the score reels reset. Additionally, they might not advance to the next ball if the bonus is not counted down correctly. In order for a stepper to work correctly, it must be relatively clean and free of sticky grease and oil. The electrical contacts must be clean and should be coated with some sort of dielectric grease. The coil and plunger need to function smoothly. Finally, it needs to step once and only once per actuation. There are often adjustments to stops and coil locations that can be made to ensure this. When you actuate a stepper by hand, it needs to move smartly from by one step to the next. If this doesn't happen, it is time to rebuild your stepper.

WORK IN PROGRESS. PICTURES AND REBUILD INSRUCTIONS COMING.

5.6 Score Reels

There are many types of score reels. Score reels are essentially 10 unit steppers. In fact, many of the parts catalogs refer to them as such. Each manufacturer has their own individual design. Within each manufacturer, there may be several designs and even variations within each design. For instance Gottlieb introduced "rat trap" score reels around 1955 on multiplayer games (Duette) and around 1959 on the single player game Miss Annabelle. Around 1966, Gottlieb moved away from the rat trap score reels to a newer, less complex design, called a "decagon" unit. However, the decagon unit itself has several iterations, with 10 sided reels, round reels and plastic parts replacing metal parts. Around 1975, they did a major redesign of the decagon unit that is cheaper and considerably easier to service than prior versions, yet it is still called a "Decagon" unit.

The point of all this is that there are many designs and iterations of these designs and you will need to figure out your particular unit for yourself, as it is unlikely that every iteration will ever be covered in a step by step guide.

Score units generally provide the following functions:

1. Step once and only once per signal

2. Provide a signal used by the startup sequence that the score reel is at zero. The majority of the time the switch is closed at zero, but sometimes it is open, so check you schematic and other score reels in the machine if you are not sure.

3. Provide a signal that the score reel did move. This is often a switch that is normally closed (end of stroke switch) and opens when the plunger moves. This can be a cause of locked on coils, so you need to be sure it opens. Some people advocate keeping them permanently open on Gottlieb Decagon units, but I don't see a need for that.

4. A signal when the unit gets to nine, this is used to "carry over the decade" at the next score. Of course the highest score unit will not have one of these, since there is no higher score reel to carry the decade over to.

5. Provide a signal to the high score and match features of a game as to exactly where the score reel is. This is typically done via the circuit board on the reel and a wiper that runs across it.

Generally, you will need to do the following to service/rebuild one of these units, minimum is usually to clean the circuit board and score reels themselves and de-gunk the unit so it steps smartly. You can go deeper as required or desired either due to the necessity of the repair or your level of comfort taking it apart.

Pull the score unit from the game and let it hang.

• Remove the retention on the circuit board

• Pull the score reel

• Clean up any gunked up, sticky moving parts with Mean Green or a similar degreaser

• Clean up the score reel with Novus. BE CAREFUL, do not clean the numbers off the wheel.

• Degrease the circuit board

• Sand the face of the circuit board with 600 grit wet or dry sandpaper, using rubbing alcohol as the lubricant.

• Apply a Teflon based lubricant to the circuit board, like Superlube or a similar product.

• Clean all the contact points.

• Re-assemble and verify the unit steps correctly and the contacts open and close correctly

5.6.1 Decagon Score Reel Overhaul

A Youtube Video of the process on a Gottlieb Decagon is here:

Teardown – (Note, I have since found out that it is a lot easier to do this if you de-solder the coils): http://www.youtube.com/watch?v=XVdUp5kVkjk

Cleanup http://www.youtube.com/user/newmantjn#p/u/13/QZVRilwjZZQ

Rebuild http://www.youtube.com/user/newmantjn#p/u/14/IMvvJCtBJc0

Epilogue - Fixing a problem: http://www.youtube.com/user/newmantjn#p/u/5/zQUHiT7BJB8

5.6.2 Rat Trap Score Reel Overhaul

Background

The Iconic Rat Trap Score Reel. Where engineering and art intersect.

According to the IPDB, the first appearance of a Rat Trap score reel was on the four player "Super Jumbo" game in 1954. It is probably not pure coincidence that this was also Gottlieb's first 4 player game. Gottlieb had made a few 2 player games with lightbox scoring, but no four player games. It is likely that the Rat Trap reel was developed to allow for four player games, as the real estate required for lightbox scoring on a four player game would have been excessive. The single player games didn't catch up until 1959 with Miss Annabelle.

The mechanism itself is fairly robust and a beautiful piece of engineering. It suffers from having a lot of parts, which probably meant that it was a little expensive to produce and difficult to assemble. Additionally, there were some adjustments within the mechanism that needed to be made, which always adds to assembly cost. The score reels themselves are gorgeous and feature black letters on a white reel, with a distinctive, yet familiar font. The Wedgeheads of the 1960's that had these score reels just ooze nostalgia and class in a way that can never be approached with a DMD display. The drawbacks, most likely the cost of the unit, lead to its eventual replacement in 1966 with the "Decagon" unit. Subway was the last game to use this classic score reel.

As you read the following procedure, please note a few things.

1. Only do what you are comfortable doing. 9 times out of 10, you will only need to clean up the circuit board, file the points and inspect the coil stops and sleeves.
2. Many of these procedures would apply nicely to a Decagon or Williams score reel. It's all the same – Take it apart, clean it, lube the circuit board, replace broken parts.
3. Take more pictures than you will need. You still will not have enough.
4. The letter/number combinations ( i.e. A-3131) are part numbers straight out of the 1962 parts list. The names are generally correct per the parts list as well (although "Rat Trap" is a term of endearment, not an official Gottlieb name).

Teardown:

• Remove the score reel assembly from the backbox. This is done by removing the two hairpin style cotter pins. It is OK to let the score reel assembly dangle
• Next, remove the three screws holding the score reel on. Note that the score reel and the grounding wheel beneath in corporate a "poka-yoke" design. Poka-yoke is Japanese for "idiot proof", but here in the States we can come up with some pretty good idiots, so you may want to mark the score reel for orientation as well. The Poka-yoke feature on the score reel is that one of the plastic buttons is larger than the other three, so in theory it can only go together one way. The top button in the picture is the largest of the three. It can be jammed together if you are not careful, so be sure to familiarize yourself with this feature, or mark it (or both).
• Next remove the score reel and the grounding wiper beneath it. Note in the picture of the grounding wheel that the top hole is much larger.

• Score Reel Disassembly
• 

  Score Reel Removal

• 

  Remove these screws. Note larger hole assembly feature

• 

  Poka-Yoke assembly feature on the ground wheel

Stop here. Ask yourself: "Do I need to take this apart further?" Or "Can I get away with just cleaning up the circuit board and maybe replacing the coil stop or coil sleeve?" This is your machine, so do whatever you are comfortable with. The directions that follow will get you through a complete overhaul. This allows for inspection and cleaning of all parts. It also may result in lost parts and misassembly.

• Remove the E clip that retains the cam and ratchet hub assembly. E clips are known to go flying, often resulting in cuss words and trips to the hardware store. Ease the E clip out and keep your finger over it.
• Remove the bottom two screws from the circuit board. Slide it out from the retaining post on top.
• Desolder the lead from the circuit board. While it is possible to work around this 10 second job, you will spend an extra half hour trying to reach things that you can't reach without a tweezers. You will also spend an extra hour hunting the pieces that go flying and two hours on diagnosing the poor switch cleaning and misassembly that will inevitably result in not having adequate access to the parts. Spend the 10 minutes desoldering and soldering. It is time well spent.
• Swing the circuit board out of the way and there you have it! Access to a mechanical engineering marvel. Take a moment to enjoy that.

• Score Reel Dissamebly - Removing the Circuit Board
• 

  Remove the E clip that retains the Cam and Ratchet Hub Assembly. Note how dirty the grease is on this circuit board

• 

  Remove the bottom two screws.

• 

  Desolder the wire to enable the board to swing out of the way.

• 

  Swing Board out of the way

• Next, remove the coil stop, coil, plunger, insulating fish paper and coil sleeve. Unscrew the two screws holding the coil stop on and remove the coil stop. Slide out the coil and lift the plunger off the pin on the Step Up Pawl. Note any worn parts for replacement. Set aside the plunger, coil stop assembly, and coil sleeve for cleaning, unless any of these parts will be replaced.
• Remove the Cam and Ratchet hub from the score reel assembly. You may need to rotate this while pulling it up. You may also need to move some of the spring loaded parts out of the way with a small screwdriver. (no picture)
• Remove the E clip that holds Step Up Pawl A-3131 on. Remove the step up pawl and spring. Set aside for cleaning and/or replacement. (they should not need replacement) You can further disassemble this part to facilitate cleaning and drying if desired.
• Remove the E clip retaining the A-5177 Drive Index Pawl Assembly on. Remove the spring and finally, the pawl.

• Score Reel Dissamebly - Removing Rotating and Actuating Parts
• 

  Used parts from the coil assembly. From L to R - Plunger, Fishpaper, Coil Stop and Bracket, Coil Sleeve

• 

  Step Up Pawl removed

• 

  Ratchet and Pawl Removal

At this point, your Rat Trap score reel is completely disassembled and ready for clean up. It should look like this.

Rat Trap Score Reel Assembly, Fully Stripped

Cleaning and Refurbishing the Parts

Circuit Board

1. The circuit board will almost always need to be cleaned up. It will likely have a coating of old, dry, sticky grease on it. This coating causes sluggish score reel response, in turn preventing the machine from scoring correctly or maybe preventing it from resetting properly, resulting in the dreaded "score motor just runs" syndrome.
2. Clean/degrease the circuit board with synthetic steel wool (a "scrubbie") and Mean Green. DO NOT use real steel wool. I prefer to clean up the circuit board in two steps. A general degreasing and a contact cleaning using Mean Green and a scrubbie followed by sandpaper with alcohol. This two step process will save you sandpaper and yield better results than a clean up with sandpaper alone – but it is your machine, if you want to skip the Mean Green step, feel free. After the intitial clean up, it should look pretty good, but we can do better.
3. Next use alcohol and 600 grit wet or dry sandpaper to resurface the copper circuit board surface. You can use rubbing alcohol or denatured alcohol.
4. Finally, coat the circuit board with a very light coating of Teflon grease. Very light.
5. Lightly touch up the point on the Grounding Wheel.

• Score Reel Cleanup - The Circuit Board
• 

  Initial Cleaning Done with Synthetic Steel Wool and Mean Green

• 

  Circuit Board After Mean Grean Degreasing

• 

  Sand with 600 Wet or Dry and Alcohol

• 

  Circuit Board After Light Sanding

• 

  Use Superlube or a Similar Dielectric Grease - Use Sparingly

Rotating and Actuating Parts

1. Take all the parts you set aside, including the ratchet parts, springs etc. and douse them with Mean Green.
2. Run a bottle brush through the holes if they are dirty.
3. Chuck everything into an ultrasonic cleaner if you have one. Scrub the parts with a toothbrush if you don't have a cleaner. Be CAREFUL! Don't lose those small parts!
4. Pull all the parts out and blow off with compressed air. You might want to put the smaller parts in a sock for this step so you don't blow them across the floor.

• Cleaning Rotating and Actuating Parts
• 

  Hose the parts down with Mean Green

• 

  Clean out the Holes with a Bottle Brush

• 

  Parts in the Harbor Freight Ultrasonic Cleaner

Score Reel

1. Clean the number surface with Novus 2 and a gentle hand. Don't clean off the numbers.
2. Coat the number surface with a coat of pure carnauba wax. Wipe off when dry.
3. Clean the inside surface with Novus or Mean Green. (or leave it alone if you don't mind the dirt)

• Score Reel Cleaning
• 

  Cleaning Supplies Used for Score Reels

• 

  Clean the Number Surface with Novus 2

• 

  Clean the Inside with Novus or a Rag Moistened with Mean Green

Coil/Coil stop/Coil Sleeve/Plunger

1. The coil stop and coil sleeve are often borderline for replacement. Generally, I figure that if they show any wear, they get replaced. The plunger itself is usually OK, or maybe could stand to have the end that hits the coil stop re-faced with a grinder. The coil is generally either perfectly fine, or completely failed. This score reel got a new coil stop and coil sleeve. Both of these parts were marginal, but once it is apart, you may as well replace marginal parts.
2. Replace the coil stop by holding it tightly in a vice and unscrewing the nut. Install the new one the same way.
3. Slip the new coil sleeve into the coil.

• Coil Stop and Associated Parts
• 

  Replacement Parts for the Coil and Plunger

• 

  Replacing the Coil Stop

Switches

1. Tighten all switch stacks.
2. Clean all switches with a flex stone, small file or folded 400 grit sandpaper. Blow out, or better yet, run a piece of paper through the switches to get rid of any grit left in the switch.

• Switches
• 

  Cleaning the Switches with Flexstone

• 

  Some Score Reels Have More Switches than Others

Reassembly

• Install the Step Up Pawl A-3131, spring and E clip. I find it easier to hook both ends of the spring on and drop the assembly over the post. Take care not to overstretch the spring if you do it this way.
• Install the A-5177 Drive Index Pawl Assembly, spring and E clip. You will likely need a dental pick, or needle nose pliers to install the spring.
• Install the Cam and Ratchet Hub. This is trickier than it looks. I will get hung up on the spring loaded parts you just installed. Rotate it, use a small screwdriver to move the parts out of the way and gently push on it while rotating to get it to "drop" a level at a time. The first time you do it, you will have to keep looking to see what it is hung up on, but soon you will be a pro at it.
• Reinstall the E clip that holds the Cam and Ratchet hub on
• Drop the plunder in over the post on the Step Up Pawl.
• Slip the coil with the new sleeve into the plunger.
• Put the fishpaper insulator over the coil stop assembly and install both pieces onto the score reel frame. Don't forget the insulator. This can result in additional swearing.

• Assembling the Rotating and Actuating Parts
• 

  Install the Step Up Pawl, Sring and E clip

• 

  Install the Drive Index Pawl Assembly, spring and E clip

• 

  Install the Cam and Ratchet Hub

• 

  Assemble the Plunger and Coil

• Slip the circuit board onto the post and install the two screws/nuts that retain it. There is some slop in the holes, so center the circuit board hole on the Cam and Ratchet hub.
• Solder the wire lead back on.
• Hold the Grounding Wheel in place, being mindful of the proper orientation – the large hold and possibly the mark you put on it.
• Put the numbered score reel in place, again being mindful of the orientation.
• Put the spider washer, A-6362 over the score reel in any orientation.
• Install the three self tapping screws to retain the score reel.
• Put the score reel back in the backbox and retain it with the two cotter pins.

• Finishing up the Assembly
• 

  Install the Circuit Board

• 

  Install the Grounding Wheel. In This Picture the Large Hole is Down

• 

  Install the Score Reel, Spider and Screws

5.6.3 Chicago Coin Machine (CCM) Score Reels

Overview:

CCM Score reels are different than many of the major manufacturers. Instead of having a switch for the decade rollover the connections are performed by the fingers on the circuit board.

• CCM Score Reels
• 

  CCM Score Reel Player 1. 1000s . This is in 0 Position

• 

  CCM Circuit Board and Fingers in 0 position

5.7 Drop Targets

Complete Teardown and Rebuild of a Gottlieb Drop Target Bank

This procedure was developed a few years ago while working on a Volley. The Volley has three, 5 target banks. Sometime after rebuilding the first one, I decided that there must be a better way. No way would David Gottlieb have put up with dental picks and the like on his assembly line. So my goal was to develop a procedure that would require only fingers, or maybe a little "help" from a screwdriver. Note that this is for a complete overhaul. You might have to adapt if you just want to change a target or two. Generally, I like completely overhauling something and not worrying about it again, ever.

One other thing to note is that Gottlieb made three or four variations on this target bank. Some have series bars, some don't. Some have bent reset bars, some are straight etc. If you generally follow these directions and take a lot of pictures, you will be fine.

One thing I have discovered over time is that a common mistake is to spend a lot of time trying to save a little time. This comes up in auto repair a lot. People will try real hard to not pull off a part which is held on by 4 bolts. So, in order to save the 3 minutes of time removing the 4 bolts, they will add an hour to the repair time trying to work around the part they should just have removed. The procedure really takes everything apart. It took about 45 minutes to completely disassemble the bank, clean every part and re-assemble. By contrast, the when I did a Big Brave bank a few years prior to this, it took me hours to get it done, since I tried to not take it apart all the way.

One more thing – you can leave some of the sub assemblies together if you don't plan on running the parts through a cleaner. For instance, you could leave the brackets attached to the back of the target bank. It's your machine, you decide how far you want to take it down.

Drop Target Bank Rebuild Procedure:

Remove Drop Target Bank from game

Playfield in Full Service Position

1. Put the playfield up in the full service position, with the playfield resting against the backbox. Use a towel to protect the playfield and backbox.
2. Unscrew all the switch stacks one by one. Wrap each switch stack in low tack masking tape or thread a 5-40 nut onto each screw to hold the switch stack together.
3. Undo the coil from the target bank. Don't let it just hang by the wires, tie it up with a piece of wire, string, tie wrap or old rubber ring.
4. Remove the screws that hold the target bank to the bottom of the playfield and pull out the target bank.

Teardown – NOTE take more pictures than you will ever need. You will still not have enough.

Rebuilt bank on the left, dirty bank on the right. Note, I helped myself out a little here, in that this was the third bank I did (so I had practice) and I had an exact target bank to reference. Not even a mirror image, which can make you stop and think for a bit.

Two Target Banks

Target Bank Ready for Teardown

The bank was completely off, some of the mounting brackets were loose from pulling it from the machine. The "front" and "back" of the target bank assume the bank is situated as shown, with the targets furthest from you. The side closest to you is the "front" and the side furthest away from you (closest to the targets) is the "back".

Drop Target Bank Teardown Procedure:

1. Remove the E clips on both sides of the rod
2. Remove the two plastic bushings that guide the rod
3. Remove the mounting bracket for the coil and rod
4. Remove the mounting bracket for the other end of the rod Note, you may need to slide the rod back and forth ¼ to ½ inch to accomplish this.
5. Remove the trigger arm return spring.
6. Remove the rod that runs through all the triggers.
7. Remove the front of the target bank.

At this point, you will have a sub-assembly like the one shown below. It should be fairly obvious that it is easy to pull off and reattach all those springs on the drop targets and triggers with the sub assembly as shown. One word of caution: Do not mix up the springs. The lighter weight springs attach to the plastic target. If you mix them up, the drop targets won't drop.

Target Bank Major Subassembly

8. Remove all the springs from the drop targets and triggers.
9. Pull out the drop targets.
10. Disassemble the rest of the steel box (if desired for cleaning)

I feel that mechanical mechanisms work best when they are clean. They were not designed to work with a layer of grunge, oil and dirt on them, so I like to clean them up prior to re-assembly. If it is your first shot at this, you might want to minimize some of the disassembly and cleaning in favor of making sure you can get it back together. That said, I like to clean the face of the drop targets with Novus, then put a generous layer of carnauba wax over the hot stamped face for protection. Next, scrub out the nooks and crannies in all the parts with Mean Green and a toothbrush. Then, into the ultrasonic cleaner, if you have one, otherwise rinse off and blow the parts dry with compressed air. BE CAREFUL not to blow you parts all over the garage. You can put the little parts in an old sock or something when you blow them off. Wipe off the wax when dry. For the very small parts, like screws, you are probably better off not washing them at all, unless you have a lot of spare parts around.

• Drop Target Cleaning
• 

  Target Bank Completely Disassembled

• 

  Target Bank in Ultrasonic Cleaner

• 

  Target Bank Clean, Dry and Ready to Assemble

Target Bank Assembly Procedure:

1. Attach the "heavy" springs to the bottom plate.
2. Attach the "back" (the side closest to the targets) to the top and bottom. Be careful and consult your pictures as it is easy to put the top on upside down, or mix up the top and the bottom. This is why you may be better off leaving these three sides of the steel box in place the first time you do this. ATTACH ALL THE SCREWS LOOSELY.
3. Drop the targets in through the holes. No, you can't put the springs on first, they won't fit through the holes.

Drop in the targets and attach the springs to the targets.

4. Stick the triggers in through the targets. Make sure you have them right side up.
5. Attach the springs from the bottom plate to the trigger.
6. Attach the springs from the target to the trigger.

• Attaching Springs
• 

  Triggers in Place, all Spring Attached

• 

  Another View

Note: You can do the prior two steps in either order. You shouldn't need any tools to do it, but a needle nose pliers, a hemostat or even a small screwdriver may help you if you have sausage sized fingers. Once this sub assembly is together, the springs will hold the triggers in place.

7. Feed in the reset arm. Make sure you have it oriented correctly. Notes: You cannot feed it in after you attach the back plate. Also, on a very long bank, you may need to feed it in prior to attaching the springs from the bottom plate to the triggers. Take care on how you position the reset arm - make sure it is on the correct side of the stop screws in the bottom plate. With this method of assembly, it is fairly obvious though.
8. Attach the front plate. You may have to move the triggers around a little to get them to go though the proper slots in the front plate. This is fairly easy though.

• Assembling the Reset Arm and Front Plate
• 

  Feed In Reset Arm

• 

  Another View

• 

  Front Plate Attached

9. If there is a series arm, now is a good time to feed that in from one side or the other.
10. Now, feed in the arm through the guides in the front plate and all the triggers, the reset arm and the series arm. Leave the E clips off of both sides of the rod for now. You may have to wiggle the trigger arms a bit to get the rod to feed through.
11. Install the reset arm return spring.
12. Install rod support on one end of the assembly and the coil bracket/rod support on the other end. Install the plastic bushings on the end of the rods.
13. Tighten up all the loose screws.
14. NOW – finally- install those E clips!

Completed Drop Target Unit

Put the entire assembly back into the game. Clean up the backside of the switches that the trigger arms actuate when the targets drop. Gunk on those is a major reason what targets only go down half way. I like alcohol for this. Verify that all targets score. Verify that when all targets are down, the series bar pulls away from the NO switch (if you have one) and the switch scores.<br.

Sit back, have a beer or other tasty cold beverage, and congratulate yourself on a job well done, secure in the knowledge that you will not have to do it again for 20 years.

5.9 Pop Bumpers

Over time, pop bumpers will need to be removed. If removal is necessary, rebuilding / refurbishing the pop bumper is recommended. Below are several reasons why removal of a pop bumper assembly is necessary.

1. The coil has melted from locking on and shorting its windings. Or, possibly the assembly has been gunked up by some unknowing repairman, who kept spraying the assembly to lubricate it. The assembly has become covered with years of built up gunk from the use of this unnecessary lubricant. The pop bumper now needs to be overhauled. Even though Williams recommends in their EM operational manuals to lubricate the coil plungers with graphite, pop bumpers should really never be lubricated.
2. Another reason is due to the pop bumper body becoming broken or cracked. Pop bumper bodies are made of plastic, and deteriorate over time. In most instances, a cracked or broken pop bumper body does not impede the proper function of a pop bumper, but they can look unsightly.
3. The final reason is related to appearance, but preservation comes into play. On the top side of the playfield, most pop bumpers have a Mylar shield or "free-floating" platter, which gets worn and looks ugly. If dirt and / or grit are present underneath the platter, (this is extremely common), the platter starts to act like sandpaper. The end result is that the platter wears away the clearcoat and paint versus protecting the playfield like it was intended to do. The only resolution is removal and / or replacement of this platter.

Gottlieb, and in the case of this narrative, Chicago Coin use "free-floating" Mylar platters. Some manufacturers such as Williams and Bally use self-adhering Mylar rings around the perimeter of the pop bumper skirt. The self-adhering style of protection may only need replacement if the Mylar ring is losing adhesion, and starting to lift away from the playfield.

For this narrative, refurbishing a pop bumper from a 1966 Chicago Coin Kicker machine will be discussed. Nearly all pop bumpers are constructed the same, so this rebuild will apply to many machines. Several solid state machines are similar, and equally apply.

Our target	This is the pop bumper that we will be restoring. As you can see the platter next to the playfield is well worn. This pop bumpers brother to the right will also need to be updated eventually.
Remove cap	The first step in working on the bumper is to remove the pop bumper cap. This is a game manufacturer / game era dependent step. In this case, we have two screws that need to be removed to access the interior. For Gottlieb games, starting with Surf Side in 1967, gently compress the sides of the cap at 3 o'clock and 9 o'clock. In doing this, the tabs which hold the cap in place come free, and removal of the cap from the pop bumper body can be done.
Remove pop bumper bulb	Once we have gained access to the internals, remove the bulb from the lamp socket, and set it aside. A good tip is to place related parts from a section into an old peanut can or similar container to keep them together. At this point, do not remove the screws which secure the pop bumper body to the playfield. Instead, turn the playfield over to access the pop bumper "guts" on the underside. Removing the playfield from the cabinet and placing it horizontally can make it much easier to work on. However, take special precautions not to crack or break plastics and other assemblies which are elevated higher than the playfield rails. The playfield should not be resting on these types of assemblies if it is turned over. Otherwise, these assemblies can and probably will break.
Pop Bumper Under playfield	Here is a look at the underside of the playfield with the pop bumper with parts identified (click on image to enlarge).
Remove mounting bracket	Remove the mounting bracket for the bumper. This is done by removing the two screws which hold the pop bumper plunger and yoke assembly to the mounting bracket. Next, remove the four screws which hold the mounting bracket to the playfield. In the case of this unit, removal of the pop bumper coil stop at the top is not necessary. On this game, one of the coil stop mounting screws has been removed, and not replaced. Probably by someone who removed it, and did not place it in a peanut can to keep the parts together, but I digress. It is worth mentioning that most other manufacturers employ a pop bumper coil stop which is integral to the pop bumper mounting bracket, and not removable. Chicago Coin, "classic" Stern, Data East, Sega, and "new" Stern are the exceptions.
Remove rod and ring	Now remove the rod and ring by choosing an appropriate socket and unscrewing the nut cap from the rods. A 5/16" nutdriver is typically used.
Pop bumper bracket with plunger, yokes, and spring removed	Once the rods are removed, the plunger assembly can be lifted from the rods. Take note how it is assembled to restore the assembly to its original configuration.
Unsolder the lamp socket leads	Unsolder the lamp socket from the wires which feed it power.
Remove screws from pop bumper body	The playfield now has to be turned over again. Remove the two screws inside the pop bumper body which secure it to the playfield, and safely put them aside. Always take care not to lose any parts.
Removed bumper	The remaining portion of the pop bumper assembly on the top side of the playfield can now be removed. Just look at that mess around the Mylar protector. Once the body has been removed, and at some point prior to reinstalling it, clean the pop bumper spoon switch with rag or towel dipped in rubbing alcohol. The spoon switch collects dirt, especially if any lubricants have bee applied to it.
Remove unwanted solder	Removal of the excess remaining solder from the lamp socket leads is necessary, if the lamp socket is to be reused. The leads will need to be clean to fit through the holes in the pop bumper base and body. If the lamp socket is not going to be reused, clip the socket leads just above the location where they were soldered. Please note that the yellow piece on the tip of the skirt finger is not typically used with manufacturers other than this era of Chicago Coin. It is also worth mentioning that Bally used metal skirt assemblies for a period during the mid-1960's.
Pop Bumper Shield	This is not a playfield restoration narrative to be sure. However, clean the area thoroughly under the old platter. After a good cleaning place down a new shield. A new platter can be purchased from the various pinball parts suppliers.
Shields new and old	These shields come in two flavors, self-adhering and free-floating. The recommended version is self-adhering, because once it is applied to the playfield surface, dirt and grime cannot get under it. The free-floating platters can be subject to the same wear as the originals, if not kept constantly clean. Ultimately, it is all a matter of personal preference which style to use. It may be necessary to cut the new replacement platter to fit. Use the removed platter as a guide for cutting the new replacement.
Pop Bumper Anatomy	Now, it's time to clean all of the pop bumper parts. This includes the skirt, base, and body. Note how all of the pieces go together to reassemble. The base is press fit into the pop bumper body and can be difficult to remove. Take your time and gently pry the pieces apart with a small screw driver, if required. Inside the base is a small spring which allows the skirt to retract to its centered, "home" position, after a pinball comes in contact with it. Take extra care with any plastic pieces which are hot ink stamped. Even the most gentle cleaners like soap and water can possibly remove the ink. Test a cleaning agent on a very, very small portion of an inked area first, before cleaning the whole inked area. The best way to clean the plastic parts is with a mild liquid soap and and warm water in the sink. On old toothbrush can be used to clean particularly dirty or hard to reach areas. Another method is to place the parts in the dishwasher. If using a dishwasher, do not put it on a heat dry cycle. Do not put plastics which are hot ink stamped in the dishwasher! Clean the rod and rings with chrome polish from any auto parts store to make them shine again. Replacement parts can be purchased from most of the recommended pinball parts suppliers.
Reassemble the top portion of the pop bumper body	Reassembly is essentially the reversal of removal. First, assemble the pop bumper body and associated parts which are located on the top of the playfield. The order in which the parts go together is the pop bumper body, the rod and ring, the skirt, the small skirt spring, and then the base. Next, insert the lamp socket leads into the top side of the pop bumper body. Make certain to use the two openings in the body, which are not intended for securing the body to the playfield. Please note that some of the pop bumper skirts will have a small pointed tip on them. This pointed tip should point to the top of the playfield when installed. Our example does not have this little skirt tip. Next, place the pop bumper body onto the playfield, and using the two screws, secure the body to the playfield. Once the pop bumper body is secured, turn the playfield over to expose the underside again.
Pop Bumper Sleeves	You will notice there is a sleeve inside of the solenoid, and the plunger moves back and forth inside of it. This is commonly referred to as a coil sleeve. It is recommended to replace this sleeve, again available from most any of the recommended pinball parts suppliers. In this example, the original brass metal sleeve is on the right, and a new nylon replacement is on the left. Each style of sleeve has a small flange on one side. When installing a new sleeve in a solenoid, make certain the flanged side is facing towards the coil stop, and away from the pop bumper spring. Some manufacturers did not use replaceable coil sleeves prior to the 1960's. In these cases, the coil sleeve is actually an integral part of the coil's windings. If the coil sleeve is brass, and there appears to be great difficulty in trying to remove it, don't remove it. Just clean it as best as possible. If the sleeve is worn through, replacement of the coil is the only solution.
Reassemble the plunger	Next, solder the lamp socket leads to the wires which feed power to the lamp. Then, place the plunger yokes over the rods, and secure the nuts to the rods. Do not over tighten these; Hercules need not apply here. Make them snug and secure. Along each step of the way, make sure the rod and ring moves freely, and that the skirt acts as if it is floating on the base. If things are not moving freely or feel restricted, go back and double check your work. See how that plunger is shining in the picture, it was cleaned and polished too.
Remount the bracket	Now it is time to remount the bracket. Secure the plunger bracket to the mount with the two screws. These two screws will typically have captive lock washers on them. Next, place the solenoid over the plunger. Pay special attention to the orientation of the solenoid lugs. Make certain the solenoid wires are facing the proper direction. Otherwise, they may get in the way when the pop bumper activates. Finally, secure the bracket to the underside of the playfield with the 4 screws.
Inspect the switches	Now it is time to inspect the switches. The switch stack was not removed, so adjusting may not be needed. However, due to age and general wear, it may need some adjustment. Equally, contacts which are slightly pitted should be burnished. It is a good practice to make certain that the skirt finger is centered within the spoon switch. Gently push on the center of the backside of the spoon switch. If the skirt finger moves at all, adjustment is necessary. Loosen the screws that mount the stack to the playfield, and adjust accordingly. Once the spoon switch is properly adjusted, push down on the skirt from the top side of the playfield. Push down at all points where a pinball can roll onto the skirt. Doing this will ensure the spoon switch contacts properly make at all possible positions.
Manually actuating the solenoid plunger	Manually actuate the solenoid plunger with you finger by pushing down on the edge of the yoke. If this case, make certain the normally closed EOS switch opens when the plunger is pulled in. In other cases, the switch activated by the yoke may be normally open. Everything should be moving freely with no binds. Check the rod and ring too for any bindings.
Pop Bumper Rebuilt	All done, she's lookin' 'more better'.

5.11 Flippers

5.11.1 Photo Identification of Different Styles of Flipper Assemblies

Late Style 2" Gottlieb Flipper from 1967 Surf Side

Late Style 2" Gottlieb Upper Flipper from 1967 Surf Side. Note- Lack of EOS switch & unusual triangular bakelite link

5.12 Power Supply Issues

Williams silicon bridge rectifier:

The function of the rectifier and capacitor is to convert the alternating current (AC) to direct current (DC), supplying DC to the bumpers, kickers, etc. The bridge rectifier would typically never need replacing as it is rated well over the voltage and current requirements of the components it supplies. If, however, the 15 amp 24 volt fuse on the mechanism panel opens, it could be due to a faulty rectifier. Disconnect the AC input to the rectifier, replace fuse, and recheck. If the 10 amp fuse located next to the rectifier opens, check all DC components I.E. bumpers, kickers etc. for shorts.

Bally silicon bridge rectifier:

Bally also used a bridge to convert AC to DC for various coils (usually flippers) in some of their games. The wiring is similar to Williams' and the diagnosis of a bad bridge/fuse blown is the same - check the end of stroke switches on the flippers, and for any stuck contacts on pop bumpers, sling kickers, etc.

6 Test Procedures

6.1 Testing with a Jumper Wire

Details here: http://www.planetimming.com/Pinball/troubleshooting/EM%20Troubleshooting.pdf

6.2 Testing with a Test Light

How to build your own test light: http://www.planetimming.com/Pinball/Pinball_EM_test_light.html

6.2.1 Electrical short troubleshooting Fuse helper

A circuit breaker aid with a blown fuse soldered in position

As an aid to finding the cause for an electrical short, you can make a circuit breaker tool to eliminate the need to constantly replace a fuse, while you investigate the cause. This could save you money in the long run. It is better to under-fuse the connection by a small amount, then to use the rated fuse rating, so a 3 amp circuit breaker could be used on a 5 amp fuse holder, or a 10 amp breaker for a 20 amp G.I. fuse holder. The very small GMA fuses (5x20mm) will probably need some kind of jumper wire setup.

• a burned out fuse of any amperage or voltage (you were saving them just for such a thing!)
• a circuit breaker of 1, 3, 5, or 10 amps, whatever amperage you require for the circuit you are troubleshooting. Buy ones like P/N 691-CMB10311C3NBA (CARLING) OR 655-W57-XB7A4A10-10 (Tyco)

Solder the burned out fuse to the spade terminals of the circuit breaker as shown in the photo. Alternatively, make a two wire female spade mini harness, and solder the bare wires to each end of the bad fuse and attach the circuit breaker that way.

7 Resources

Online help is available by posting a request to the rec.games.pinball newsgroup. If you're new to newsgroups, Google Groups provides an easy-to-use interface: http://groups.google.com/group/rec.games.pinball/ Create a post with "Tech EM: " in the heading and provide as much information as possible about the problem.

There is also an "empinbalmachines" group on Yahoo! Groups. http://games.groups.yahoo.com/group/empinbalmachines/

Team-EM provides help via e-mail. From the Team-EM site at http://www.team-em.com/ you can send an e-mail to the team (the link is at the bottom of the page).

Here is a handy file showing what fits what and the dimensions for coils and sleeves.

File:Coil Sleeves.pdf

8 Game Specific Problems and Fixes

Example would be servo controller on Independence Day pinball

9 Repair Logs

Did you do a repair? Log it here as a possible solution for others.