Last update: 07/25/2017.
Pinball machines contain potentially lethal voltage. Dangerous voltage may remain for a period even after it is unplugged. Prior to opening a pinball machine, be certain to unplug it, then turn it on to insure that it was actually unplugged. It is recommended that the machine be allowed to sit several minutes to allow any remaining power to dissipate. Repair should be left to properly trained personnel. If you are not qualified, you should not work on a pinball machine.
Solvents such as isopropyl alcohol are flammable and should be used only in a well ventilated area. Do not operate the pinball machine until the vapor has dissipated. Follow all the warnings on the container. Never use lubricants such as WD40 as that can lead to a potentially flammable - explosive situation.
Proceed at your own risk!
Pinball machine can be divided into two general areas, the playfield and the backbox. There are also two general categories of pinball machines, solid state (SS) and electro-mechanical (EM) machines. SS machines have digital displays that power up when the machine is turned on. EM machines use mechanical reels that spin to display the score.
Maintenance of SS and EM playfields are similar. However, the similarity ends there. EM machines use relays, motors and switches to run the game. SS machines rely on electronic circuit boards (PCB) to control the game.
The first step is to identify your pinball machine type and model. An excellent resource is the Internet Pinball Database. Look up your pinball machine on this database to determine what type it is. Find out the manufacturer, the year, and the type: Solid State Electronic (SS) or Electro-mechanical (EM). If your machine is solid state, also note the MPU type. Keep this information handy for dealing with parts suppliers and repair people.
It is always helpful to have the operating and repair manuals. For older machines, this may be a single manual. For later machines, usually two or even three manuals may be needed. These manuals can usually be purchased at Steve Young's The Pinball Resource, Marco Specialties, or Mayfair Amusements. If your machine was manufactured by Stern, Sega or Data East, the manuals may be available from Stern Pinball, Inc.
If you are buying a used game, the chances are pretty good that a wrong fuse was installed at some point. If it is large difference, then a problem could cause severe damage to your new pinball machine or even a fire. It is very important to check that the proper values are installed. For more information on locating the fuses, see "Fuse locations".
Regular maintenance of a pinball machine can keep it running smoothly and maintain its resale value. Prior to starting, see the Caution above. The supplies suggested below are available from companies that supply pinball parts.
Most maintenance can be accomplished with supplies found in local stores. Some materials may have to be ordered from pinball parts suppliers. The following parts may be needed (will vary depending on the machine):
Nice To Have But Not Required (unless doing board work):
The pinballs wear, get chipped and can contribute significantly to the playfield wear. It is recommended that pinballs be replaced regularly. New pinballs are inexpensive and can be obtained from the parts suppliers listed below. Don't save a few dollars and ruin a playfield.
The condition of the playfield can determine the resale value of a machine. Additionally, dirt on the playfield can slow the play down. As an owner, a playfield is easy to maintain.
To access the playfield, you will have to open up the machine and remove the cover glass.
If you find it necessary to tilt up the playfield, it is recommended that you remove the pinball(s) first. Otherwise, raising the playfield may eject the pinball, which could damage the playfield or backglass. Removing the pinball can be simple on single ball machines or tricky on multiball games. For single pinball games, you may be able to reach in and remove the ball, or manually press the solenoid ball eject mechanism. For complex SS games, it may be easier to enter the service menu to eject the balls. Consult the repair or operating manual for the specific procedure.
The first step is to clean the playfield. Novus #2 is the recommended cleaner. Follow the instructions on the containers. On clearcoated playfields, use this sparingly since these cleaners are mild abrasives and remove some of the coating.
Plastic ramps can be cleaned with Novus plastic polish - Novus #1. Another alternative for plastic is Plexus Plastic Cleaner.
The playfield should be waxed regularly. This will help prevent wear and make the game play faster.
Purchase a soft cloth like a microfiber towel to reduce surface scratches. A t-shirt works but can leave surface scratches that could be visible in a newer clearcoated playfield.
For a complete guide to playfield cleaning and restoration, see the links at the end of this page.
The general rule is that you should always replace the rubber rings on your playfield with the same color that the games came with. However, it is difficult to know for certain what color rings were intended to be used with the game.
EM games should always have white rubber rings. Black rubber is much harder and it could damage the posts of these older machines.
Newer games (1995 or newer) were usually shipped with black rubber rings. The black rubber rings do not show dirt as easily and this could be the real reason for the change. However, the harder black rubber rings have less bounce than the white rubber rings. Replacing the black rings with white ones may speed up game play. It also might (or might not) lead to more breakage with the faster bounces.
Some collectors feel that the black rings can contribute to dirt on the playfield. White rubber rings may not cause as much dirt as they age but they will look dirty sooner.
Games with ramps, either wire or plastic, are more complex to disassemble. Some games like White Water have four ramps that intertwine with each other. Disassembly and reassembly requires a great deal of patience and care.
While you have the machine apart to replace the rubber rings, it is a good idea to clean and wax the playfield.
When reassembling, sometimes wood screw holes are too large or have been 'stripped'. An easy fix that usually works is to insert a toothpick into the too large hole, then tighten the wood screw. If this does not work, try a mixture of sawdust and wood glue. For really tough situations, try Mr. Grip.
Note: I will soon add a section on how to disassemble, clean and reassemble a pinball machine.
Playfield switches control the scoring of the game. They can become dirty or bent and fail to activate scoring. Usually, all that is needed to fix the problem is cleaning or adjustment.
There are three types of switch points: gold plated, silver, and tungsten (and sometimes copper). Tungsten are designed for high current and are used for pop bumper, flipper and EOS (end of stroke) switches that directly power the pop bumper coil itself on EM and early SS games. Silver points were typically used for relay contacts, are medium to high current (depending on size and shape of point), and are not used in SS pins. Silver tarnishes and will cause little to no connection even when new if used in low current applications such as those found in SS games. Gold plated points were used once games went SS and low current, low voltage like in the switch matrix and EOS in mid to early 1990 games. The gold flashing will not tarnish like silver, but still needs to be clean of any debris or coatings.
Never use contact cleaner on any switches. Some switches (most in EM games) use high voltages and cleaners are not suitable. Use of these cleaners can lead to switch failures or even fire.
The first step is to test the switches. The easiest method is to open up the game, remove the cover glass and then manually manipulate the switches. This can be accomplished with a pinball or a push with your finger. If it works, leave it alone.
If several switches do not operate and you have a SS game, look at the switch matrix in the operating or repair manual. If the non-operating switches fall in the same row or column, then it may be a problem with the wiring or the circuit board.
The switch cleaning procedure will be different if you have and EM or a SS game.
Adjusting Playfield Switches
Properly adjusting switches is an art. Many, who are new to this hobby over adjust switches. It is not unusual to see switches bent to unusual angles and they never quite make proper contact. The first step is to get the proper tools. While using needle nose pliers can work in a pinch, their tapered tip usually causes the switch to bend or twist. A switch adjuster tool is a must for a pinball machine owner. While you are ordering, be sure to get a flexstone for cleaning high current tungsten switches. Use the switch adjuster tool sparingly to change the gap a little at a time. Too close, and the vibration of the game can cause the switch to make contact. Too far apart, the the switch will not make contact when it should.
Adjusting Pop Bumper Switches (Adjustments and Other Causes of Malfunctions).
With EM games, the full power to fire a relay or solenoid travels through the playfield switches. To clean these switches, 400 grit sandpaper or a flexstone file is recommended. Flexstone files can be ordered from pinball supply houses.
The switches that power the flippers and those at the flipper switches (EOS or end of stroke) handle higher currents and are designed differently. They can be filed with a standard metal file, a flexstone file, or they may need to be replaced. Worn or dirty flipper and EOS switches will lead to weak or non-functioning flippers.
In addition to the switches located under the playfield and the flipper switches, EM games have switches in the backbox and, usually in the cabinet under the playfield. Dirt or wear on these switches can lead to malfunctioning games.
SS machine switches work the same way as EM switches, except these switches have only low voltage (5 volts) flowing through them. That means they are less likely to be damaged by arcing and high current.
Most of these switches have gold or silver contacts and should never be cleaned with sandpaper or files. Instead, use a non-abrasive cleaner such as a piece of cardboard or business card. Another method is to use a q-tip and a small amount of isopropyl alcohol (not rubbing alcohol) on the q-tip. Caution, alcohol is flammable and overuse can lead to a fire.
The only switches in a SS game that may require filing or sanding are the EOS (end of stroke) switches located on the flipper solenoid, and some flipper switches. For older SS games, the full current flows through these switches and they need to be cleaned following the method described under Cleaning EM switches. The only exception is machines controlled by Fliptronics circuits or similar designs. Fliptronics EOS switches handle low voltages and should never be cleaned with sandpaper or other abrasives. They must be cleaned following the same procedure outlined for SS leaf switches, with a q-tip and isopropyl alcohol . Fliptronics switches can be easily identified because they are not touching (normally open) when the flipper is not in use.
The flipper switches, located just inside from the flipper buttons may need cleaning. On early SS games, these have the full power going through them and can become pitted and worn. These switches should be be cleaned following the same procedure outlined for the EM leaf switches or replaced. Newer SS machines are low power and should only be cleaned with a piece of cardboard or a q-tip and alcohol. The latest machines used optical switches and should not be cleaned. There are two ways to tell if you have full power switches: 1) if they appear pitted or severely worn or 2) if you see a bright electrical arc while operating the flippers, then they are full power and need to be cleaned like EM leaf switches.
Microswitches are enclosed and cannot be cleaned. If they malfunction, they may need to be physically adjusted or replaced.
Opto switches have a LED (transmitter) and a receiver. It is possible to physically adjust these switches. They may be cleaned with a q-tip and isopropyl alcohol. However, when they malfunction it is usually a sign that they need to be replaced or there is a problem with the circuitry. It is usually the transmitter that fails, but these should be replaced as matched pairs. Some opto's use light of different wavelengths and a certain transmitter and receiver may not work well together. It may be possible to see if a transmitter is working by looking at it through a digital camera's LCD viewfinder, but only if it is possible to see straight on. In a viewfinder, the LED will appear to glow.
Magnetic switches act by sensing the presence of the metal pinball. They are sealed and cannot be cleaned. Malfunction usually means that the switch has failed or there is a problem with the wiring or the circuitry.
Capacitors were used, primarily, on early Bally and Stern SS pins. Capacitors are there for a purpose. Some switches, such as targets get hit so briefly that the computer does not register them. The capacitor helps to simulate a longer hit so that the computer can register the points.
However, there is a downside. Caps can pick up electrical noise, such as a solenoid firing and send a signal to the computer giving a false switch hit.
That said, Bally especially went overboard installing caps where they are not needed. Some think they are not needed on roll over switches, although it is possible for a ball to fly through a lane and not register. Drop targets never need them. Targets usually need capacitors.
If a switch appears as stuck 'on', yet inspection indicates that the switch is not closed and it has a capacitor across the switch, try removing the capacitor. Removing it may fix the short or stuck on switch. Try playing the game. If the switch registers properly, you can leave the capacitor off.
All SS switches are in a switch matrix and must have a diode in order to work properly (note that EM switches do not have diodes). If this diode is missing or shorted, then activating that switch will give wrong information to the computer and tell it that other switches have also been closed. If the diode has failed open, then that switch will never operate.
Troubleshooting a failed open diode is fairly easy - the switch will not work. Troubleshooting a missing diode is done by inspecting switches - a rather tedious but usually necessary process. However, troubleshooting a shorted diode is not easy. To find a shorted diode, one must test a diode using the diode test setting on a DVM one at a time. It is better to do this with the column and row plugs removed from the CPU / MPU board. It is possible, by using the switch test in the pinball machine, to narrow the problem down to 4 or so switches. Doing this involves some pretty involved sluthing. For more detailed information, see this great article on switch matrix troubleshooting and theory.
All solid state (SS) machines have batteries to maintain the machine memory. The memory retains settings and other information such as the high scores. Batteries will leak with time and when they leak, they can destroy the circuit board (PCB) around and below the location of the batteries. It is important to replace the batteries with fresh ones annually. It is best to pick a time of the year, such as new year's day, to replace your pinball batteries along with the smoke alarms in your house.
To replace the batteries, it will be necessary to remove the translite or backglass and open the backbox. The batteries are located on the main board in the backbox. After you have replaced the batteries, it is a good idea to mark the date on them with a sharpie. That way, you can tell at a glance how old they are. If you are removing batteries that are only a year old, don't throw them out! They are most likely still good. Keep them and use them in your remote controls or other applications. You just don't want them sitting in your pinball machines for years and years.
The batteries can be replaced with the power on. This will save the settings, the high scores, etc. However, this must be done very carefully (see caution). In addition to the standard precautions, care must be taken to install the batteries in the proper direction (+ to the + side) with the power on. While the voltages around the batteries are typically low, there are other much higher voltages nearby. Accidental shorting of those voltages can destroy circuits and be quite hazardous.
Some pinball machines have been modified so that the battery pack has been moved off the circuit board, usually to the bottom of the back box. Other machines have been modified so that the batteries have been replaced with a large capacitor and these do not require routine maintenance.
The best way to avoid issues with leaking alkaline batteries is to get rid of the batteries altogether.
Electro-mechanical (EM) pinball machines do not have batteries.
Light bulbs burn out and, for the most part, they are easy to replace. Identify what type of bulbs your machine uses and order a supply from the parts suppliers. If you have a repair manual, the types used are listed. If not, it will be necessary to open your machine and look at the base of the bulbs. Always turn off the power prior to removing or replacing a bulb. If the power is left on, it is possible to short the socket or wiring to other higher power circuits and this can damage / destroy the circuitry.
Prior to tilting up the playfield, be certain to remove the pinballs to prevent damage to the game (see above).
Games use several different types of light bulbs. These are located on and underneath the playfield and behind the backglass. Some of the bulbs are general illumination lights while others are flasher lights. It may be necessary to remove the playfield plastic to access the bulb. The type of bulb can be identified by removing the bulb from the socket and look at the metal base of the bulb where an identification number is stamped. If your machine uses #44 lamps, #47 lamps can be substituted. #47 lamps use less power and run cooler than #44 lamps. Lower power will put less stress on the circuitry and are less likely to warp the playfield plastics.
LED's can be substituted for standard light bulbs. LED's have the advantage of using much less power than standard bulbs. They also run much cooler. LED's can be brighter. LED's are not without disadvantages. LED's can be much brighter and the light can be focused. Some report a strobing or flicking which can be annoying or cause headaches. Also, LED's run on DC while many bulb circuits run on AC LED's are much more expensive than standard bulbs, but can last much longer.
Some light bulbs are located in the pop bumpers. To access, you will need to remove the pop bumper cap. Some caps are snap-in and care is needed when removing to not break the caps (Eight Ball Deluxe, for example). Others are held in place by small screws. To access others, it may be necessary to remove a ramp or other playfield items.
Cleaning a playfield and replacing the rubber rings involves disassembling the playfield components. That is a great time to replace those hard to reach bulbs. Playfield bulbs are cheap, so just replace those that are covered by playfield plastics or in other hard to reach places. All lamps are referenced by numbers on the metal base and these can be hard to see. Order the same type of lamps from one of the suppliers listed below. The only exception is if your game uses #44 bulbs (see above paragraph).
The sockets that house those bulbs are a constant source of aggravation for owners. The lamps will flicker off leading the owner to think it is burned out only to flicker back on. The source of that problem is usually the socket themselves, especially those for bulbs with a round base. These sockets are not made to last very long. Sometimes the only solution is to replace the socket. However, that can be costly and involves unsoldering and resoldering two wires to every socket. Owners have developed tricks that can sometimes restore these sockets. One is to clean the socket to remove the oxidation that accumulates over the years. Many suppliers have bulb socket cleaners specifically designed for this task. Others use a Dremel at very low speed, with a rough sandstone attachment to accomplish a similar action. Another cause of flickering lights is due to the washer drying out. A small drop of household oil will cause the washer to expand and help insure better electrical contact. Yet others will swear the only fix is to solder directly to the moving parts. That can be tough because the build up of oxide and oils make it difficult for the solder to stick.
There are generally two types of backglass. Older games used a backglass that was created through a silkscreen painting process. Newer machines have a backglass that is usually referred to as a translite.
A silkscreen backglass can peel, chip, craze or flake. To preserve its beauty, it can be sealed with a Krylon clear coat spray. This is easy to do and will preserve your backglass for years to come. For more information, visit the PinballHQ website. Clean a silkscreen backglass very carefully. Since these are painted on and can become fragile with age, any physical contact can remove paint. If you must clean, use nothing more than a damp cloth and nothing stronger than water.
When restoring a backglass, the general rule is that it is better to leave an imperfect backglass alone. Usually a backglass with some flaking looks better than a poorly touched up backglass.
Translites do not generally suffer from age related damage and should not be treated. NEVER clean a translite with anything other than a damp cloth. Cleaning the translite with a typical glass cleaner may remove the translucent white background and will ruin it. Minor spots where the white has been removed may be carefully touched up with a small dab of white out, but are more often best left alone.
When moving parts start to stick or malfunction, many owners reach for lubrication to solve the problem. In the long run, lubrication causes more problems than it solves. The addition of lubrication leads to gummed up moving parts. Never lubricate any parts unless instructed by the repair manual. Pinball parts, for the most part, are made to run dry. Never ever use common lubricants such as WD40. Many, including WD40 are flammable and can result in fire.
To repair a balky or sticking part, it is best to disassemble the part and clean it with 91% isopropyl alcohol. For solenoids, it may be necessary to replace plastic or metal sleeves and install new springs in order to restore the part. Flippers and their components wear out. The only solution is to order and install a rebuild kit available from pinball parts suppliers. A rebuild kit is easy to install for those who are handy with a screwdriver. For other moving parts, it may be necessary to replace the springs. Springs are cheap and easily obtainable from pinball supply houses. Be certain to allow any flammable liquids to evaporate prior to starting the machine.
Lubrication is required where metal parts hit metal parts. This is especially common in EM pins. This includes disks that spin and contacts press down on another disk. Use special lubrication available from pinball suppliers. Some report good results using Teflon grease. Use sparingly.
Motors with gears and bearings usually require grease. Newer ones may be sealed and cannot be greased. Those with plastic parts generally are not greased.
A common cause of a non-working pinball machine is a blown fuse. Pinball machines have many different fuses. These can be located in the backbox, under the playfield, or in the area below the playfield.
Prior to inspecting the fuses, be certain that the machine is unplugged. Sometimes it is possible to identify a blow fuse by looking at it. However, the only way to be certain that a fuse is good is to check it with a voltmeter. Set the voltmeter to resistance and set it to the lowest resistance value. Check to insure that your meter is working by connecting the leads together. The value on the voltmeter should read near zero (0.1 - 0.4 ohms is typical). Remove the fuse from the holder and connect a lead from the voltmeter to one end of the fuse and the second voltmeter lead to the other end. If the fuse is good, the meter should read near zero.
The proper value for the fuse will be listed on a small piece of paper attached to the machine box, playfield, or in the manual. Unfortunately, the fuse being replaced may not be the correct value, so be certain to check. There are three basic types of fuses:
*Slow Blow/ Time Lag/ Time Delay/ Slo-blow fuses
*Fast acting fuses
*Very fast acting fuses
Fuses are also rated by their current (amperage) capability. Be certain to always use the correct value. Never put in a larger current fuse then specified.
More detail about locating, checking and replacing fuses is located here.
It Still Does Not Work - I am certain it is not the fuse(s)
If you have a (EM) electro-mechanical machine, it could be the contacts between the relays, a switch that is not closed, a bad tilt switch or, oh hundreds of stuff. Some more help on EM pins can be found here.
If you have a solid state (SS) game, it could be a bad connector or one that has just come loose, a connection between boards, an IC loose in its socket, bad solder joint, a blown component or just about a million other things.
It is a good time to ask, "What are my capabilities?" I have seen many fine machines ruined because owners tried to do what they were not capable of doing. At this point, it may be time to do more detailed research, contact a repair facility, or find a very good, competent friend. If looking for help, please see these FAQ. If willing to do some more research, please consult the external links to repair information. Please note that these links assume a basic knowledge of electronics as well as the ability to solder. If you do not have these skills, then these resources may be to advanced.
This website has a selection of information for those who are skilled in repair and have a knowledge of electronics. Note that these should only be undertaken by qualified electronic technicians.
Are you at the point where you can solder and replace circuit board components? If so, then learning how to use a Digital Logic Probe is a great tool to use. Definitely for qualified electronics technicians only.
SS pins have plugs that are notorious for burning or becoming broken. Instructions on crimping connectors help.
Those AA batteries will leak and ruin your CPU. Find out how to put in memory capacitors, NVRAM and button (watch batteries).
The plasma displays used on all SS pins wear out. Unfortunately, replacement displays for early (non-DMD) pins are either impossible to find, or extremely expensive. Manufacturers are making replacement displays that are LED's. A step by step procedure makes this process easier.
The high voltage board supplying power to Williams / Bally DMD's frequently needs to be rebuilt. Great Plains Electronics sells a kit of parts. I created a marked photograph of the DMD board to make it easier to identify the parts that need to be replaced.
Replacement for worn out playfields are difficult to find. For many years, mylar overlays were the only alternative. Although some playfields are now being remanufactured, overlays may still be available at about 1/3 the price. Here are instructions for how to install a playfield overlay.
Working on a Gottlieb System 80 can be quite a challenge. There are many excellent resources on the Internet. However, here is a hint as how to make that CPU output test signals that make it easier to trace problems.
Cleaning up a pinball playfield can be a pain, but it is made easier with a pinball rotisserie. Main article.
Your EM pin was working fine. Or you purchased one on the cheap and figure you can repair it. Really?
How to install as shaker motor on the original Lord of the Rings pinball machine by Stern. Main Article.
Looking for repair help? Please see these FAQ.
Comments and suggestions are appreciated. Email me at
Please let me know of any inaccuracies, updated information, etc. Looking for repair help? See FAQ prior to contacting me.
Mr. Pinball - Upcoming events. Classified. The site to go for current information.
PinballHQ.com - Maintained by Clay, this was the mother load of repair information for the advanced pinball repair. Much of it was removed in April of 2011. Portions have been restored since that date. Great EM repair information as well as restoration details.
Specialized Repair Information
Introduction to Electronics - YouTube video instruction training starting with the basics
Restoration Guides - How To Bring A Pin Back From The Dead
PAPA - Perhaps the most detailed and complete pinball playfield restoration guide.
Rivets - for targets, ramps, brackets, etc.
Replacing Rivets - How to remove and then install rivets on ramps, plastics, etc.
Steve Young's Pinball Resource - Call for parts. No credit cards, but low prices. Licensed for Gottlieb parts. Large supply of hard to find parts.
Circuit Board Parts / Electronics
Great Plains Electronics - GPE is the most comprehensive and lowest priced electronics supplier. Parts for circuit boards.
Cliffy Protectors - Playfield protectors that cover up existing damage.
LED Replacement Bulbs - Make the game extra bright and easier on the circuitry
Pinball Life - Great supply of 3 LED bulbs for extra brightness. Their "warm white" LEDs are great replacements that look traditional.
K's Arcade - Great prices on replacement displays.
Decorator Supply - Protect the playfield plastics from being broken.
Internet Pinball Database - Complete and extremely useful. Manuals to download plus more.
Get Your Machine Repaired
Circuit Board Repair - Mail in service to get your boards repaired from the reliable Steve Kulpa
Pinball Locator - Find pinball machines to play in your local community.
Pinball Expo - Chicago, IL late October. Granddaddy of them all.
PinballNews.com - Current and late breaking news in the pinball machine world. Covers pinball machine conventions, shows and happenings around the world
International Flippers Pinball Association (IFPA)
Stern Pinball, Inc. Manufacturer of commercial pinball machines. Located just outside Chicago, IL
Rec.Games.Pinball - the oldest and most active pinball discussion group on the Internet, also available via newsgroups distributed via NNTP
Boston Pinball eBay Results - Tabulated averages of sale prices of pins on eBay. A great reference, but with rising prices, these can be a bit low.