Difference between revisions of "EM Repair"

Revision as of 08:27, 29 May 2011


Note: This page is a work in progress. Please help get it to a completed state by adding any useful information to it.

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 operate on 6.3V and 25V AC which is safe. However, line voltage will be present from the line-in cord to the primary side of the transformer. Also, some machines have coils that operate on 120V so some relay switches and score motor switches have 120V present on them. Finally, some older machines have 120V going to the start switch. On these games you should check to make sure the fish paper insulation is still in good condition.

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 foreign brands, such as Recel, Playmatic, and Rally. There were many companies that only produced a few games, especially early on.

A quick search of the Internet Pinball Database:

http://www.ipdb.org/search.pl?gtype=EM&searchtype=advanced

Shows that between all the manufacturers, there are over 3403 games within this very broad category.

4 Technical Info

4.1 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?)

Gottlieb Start-up Sequences from the 1970s

There is a great repository of Gottlieb start-up sequences gleaned from numerous game manuals here:

http://www.xmission.com/~daina/tips/pub/emTips.html

70s Williams Start -Up Sequence (4 player)

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).
The end of stroke (EOS) switch on the CREDIT UNIT decrement coil energizes the COIN relay.
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.
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.
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.
The SCORE MOTOR runs until all score reels and the BONUS UNIT reach the zero position.
The RESET relay decrements the BONUS UNIT until it reaches the zero position.
When the BONUS RELAY drops out it energizes the OUTHOLE relay through a different BONUS UNIT zero switch and through the SCORE MOTOR.
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.

4.2 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

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 :)

5.3 Coils

5.4 Relays

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.

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.
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.
Take more pictures than you will need. You still will not have enough.
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 Dissamebly
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

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.
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.
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.
Finally, coat the circuit board with a very light coating of Teflon grease. Very light.
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

Take all the parts you set aside, including the ratchet parts, springs etc. and douse them with Mean Green.
Run a bottle brush through the holes if they are dirty.
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!
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

Clean the number surface with Novus 2 and a gentle hand. Don't clean off the numbers.
Coat the number surface with a coat of pure carnauba wax. Wipe off when dry.
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

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.
Replace the coil stop by holding it tightly in a vice and unscrewing the nut. Install the new one the same way.
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

Tighten all switch stacks.
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

5.7 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

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.

Playfield in Full Service Position

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.

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

5.8 Roto Targets

5.9 Pop Bumpers

Over time, you will find that your pop bumpers will need to be rebuilt. I have found that there are two general causes for a rebuild. One being the coil has seized up from a short or has been gunked over by some unknowing repairman who kept spraying the bumper solenoid to lubricate it. Now, it's filled with gunk stuck to the lubricant and needs and overhauled. Pop bumpers should NEVER be lubricated in any way.

The other reason is appearance.On the playfield the pop bumpers have a mylar shield that gets worn down and looks ugly, and needs to be restored. Such is the case for our example.

For this narrative I will be discussing refurbishing a pop bumper from a 1966 Chicago Coin Kicker machine. I have found that nearly all pop bumpers are constructed the same so this rebuild will apply to many machines, even solid state games.

Our target	This is the pop bumper that we will be restoring. As you can see the shield 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 dependent step. In this case we have two screws that need to be removed to access the interior. On Gottlieb games often the cap is removed by gently compressing the cap leaves and lifting the cap out of the pop bumper base.
Unscrew Base	Once we have gained access to the internals remove the bulb from the lamp socket and set it aside. As a hint whenever I am working on a section I put the parts in an old peanut can to keep them together. After removing the bulb remove the two screws holding the pop bumper base from the playfield and safely put them aside. Always take care not to lose any parts. You will notice that after these screws have been removed you will not be able to remove the pop bumper from the playfield. It is still held on by the ring and rod assembly and by the lamp socket wires. From here we turn the game over to give us access to the pop bumper guts under the playfield. I have removed the playfield from the cabinet to make it easier to work on.
Pop Bumper Under playfield	This is the under playfield look at the pop bumper with parts identified.
Remove mounting bracket	The next step is to remove the mounting bracket for the bumper. This is done by removing the two screws that hold the solenoid bracket and removing the four screws that hold the entire bracket to the playfield. Note that you do not need to remove the plunger stop bracket at the top. On this game one of these top 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.
Remove rod and ring	Now remove the rod and ring by choosing an appropriate socket and unscrewing the nut cap from the rods. Once the rods are removed the plunger assembly can be lifted from the rods. Note how they are put together to restore it to original configuration. Remove rod and ring .
Unsolder the Lamp	Remove unwanted solder Unsolder the lamp connections from the GI wires. This is all that is holding the remaining pop bumper body to the playfield. You will need to remove all of the excess remaining solder from the lamp wires as they will need to be clean to fit through the holes in the pop bumper base. Removed bumper Once the solder is cleaned up the entire pop bumper assembly can be extracted from the playfield, just look at that mess around the mylar protector
Pop Bumper Shield	Sheilds new and old This is not a playfield restoration narrative to be sure. However, clean the area throughly under the old shield. After the good cleaning place down a new shield. A new shield can be purchased for the various Pinball Suppliers. These shields come in two flavors, sticky and non-sticky. I prefer the sticker version as once down no more dirt and grim can get under them. The loose shields can be subject to the same wear as the originals. This really is a matter of preference. It may be necessary to cut the new replacement shield to fit. Use the removed shield as a guide to cutting the 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 a 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 an body is a small spring that keeps the skit floating around and responding to pinball coming into contact with the skirt. I wash the parts with soap and water in the sink. I suppose that they can also be put into the dishwasher for a cleaning, I do not do put them in the dishwasher. I will clean the rod and rings with chrome polish from the auto parts store to make them shine again. All of these parts can be purchased from the pinball suppliers.
Pop Bumper Sleeves	Back to the solenoid, if you will notice there is a sleeve inside of the solenoid that the plunger moves back and forth inside. It is a good idea to replace this sleeve, again available from pinball suppliers. In this example there is metal sleeve and the photo shows next to a replacement nylon one. The sleeve fits inside of the solenoid and has a small lip that goes on the side of the solenoid away from the spring.
Reassemble the plunger	Reassembly is pretty much a reversal of removal. Place the pop bumper body onto the playfield and use the small lamp leads to hold it to the playfield. Bend the leads a little so that it remains in place and turn the playfield over to expose the guts again. Some of the pop bumper skirts will have a small tip on them. This top should point to the top of the playfield when installed. Our example does not have this little skirt tip. First, solder the GI lamps electrical wires to the lamp leads. Then place the plunger bottom assembly through the rods holes and place the nuts on the rods. Do not over tighten these guys, Hercules need not apply here. Make them snug and secure. Along each step of the way make sure the rods and ring move and that the skirt acts like it is floating on the base. If things are not moving or feel restricted go back and 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. First re-secure the plunger bracket to the mount with the two removed screws. These two will have lock washers on them. Watch the way the solenoid is reinstalled. Make sure the wires are to the correct side or they could get in the way of the bumper action. Finally, secure the bracket to the underside of the playfield with the four (4) removed screws.
Check you switches	Switches Now it is time to check your switches. The switch stack was not removed so should not normally need adjusting. Move the skirt around and see if the spoon switch makes and breaks contact. Also self activate the coil with you finger and see if the EOS switch breaks when the plunger is pulled in. Everything should be moving smooth with no binds. Check the rod and ring too for any bindings.
Pop Bumper Rebuilt	All done, she's lookin' 'more better'.

5.10 Kickers/Slingshots

5.11 Flippers

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 in some of their games (usually flippers). 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

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.

@@ Line 622: / Line 622: @@
 '''Bally silicon bridge rectifier:'''
-Bally also used a bridge to convert AC to DC for various coils in their games (usually flippers).  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.
+Bally also used a bridge to convert AC to DC for various coils in some of their games (usually flippers).  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.
 ==Test Procedures==