Batteries in Pinball Machines

Since Pinball Machines became electronically controlled, batteries have been used to keep the settings when the machine was turned off. Batteries keep the "High Scores", "Game Adjustemts" and "Bookkeeping" from being lost when the pinball has been powered down.

There are 3 main types of batteries used by the different pinball manufacturers:

1. AA batteries (standard household type)
2. NiCad batteries (in AA size, 3 x button cell or plastic package types)
3. Button Cell batteries (watch battery type)

AA Batteries

The AA battery (a.k.a. LR6, FR6 and R6) is the most commonly used battery in pinballs. These batteries are usually in a group of 3 to provide 4.5Vdc to the RAM IC, which stores the information needed to be saved when the power is lost.

AA batteries can keep the settings for a pinball for up to 2 years with no power applied in that time (although this has not been confirmed). After this time, the batteries can start to leak their battery acid and corrode the circuit board.

Modern batteries should take much longer before they start to leak (around 4 to 5 years), but there is never any guarentee. In fact, it is possible for the cheaper batteries to start to corrode before they have been in use for 1 year!

So what does this mean to you? Well, you should be changing the AA batteries in your pinball every year... Without fail.

This way the battery acid cannot leak, and therefore will not damage the MPU / CPU circuit board. Battery corrosion can be very expensive to repair, and it is not always possible to replace the corroded MPU / CPU board.

There is one more thing to consider... If the power is turned off to your pinball machine when you change the batteries, you will loose all the settings - including your hard earned High Scores! You can change the batteries with the power turned on, but be careful while doing this. This will ensure you do not have to set the machine back up, and work hard again to achieve the "Grand Champion" score.

AA Batteries are used in:

Atari ('79): Generation 2
Bally (mid '89 - '98): System 11, WPC & WPC-95
Data East ('87 - '94): Data East MPU
Sega Pinball, Inc. ('94 - '99): Data East MPU & WhiteStar
Stern Pinball, Inc. ('99 - '05): WhiteStar
Williams (late '77 - '98): System 3 & 4, System 6 & 6A, System 7, System 9, System 11, WPC & WPC-95

This is not a comprehensive list of pinball manufacturers that used AA batteries.

NiCad Batteries

NiCad batteries are the second most commonly used battery for pinballs. These batteries are either of an "AA" size, 3 x button cells encapsulated together, or as a plastic box. They generally provide 3.6Vdc to the RAM IC, which stores the information needed to be saved when the power is lost.

NiCad batteries can keep the settings for a pinball for up to 2 years with no power applied in that time (although this has not been confirmed). After this time, the batteries can start to leak their battery acid and corrode the circuit board.

Modern NiCad batteries should take much longer before they start to leak (around 4 to 5 years), but there is never any guarentee.

So what does this mean to you? There are a few things you can do when you have a machine that uses a Ni-Cad battery:

1. Replace the NiCad every few years
2. Replace the NiCad with 3 x "AA" batteries in a battery holder using a protection diode
3. Replace the NiCad with a "Memory Capacitor"

To replace the NiCad battery, you will need to have soldering skills or know someone who can do it for you. This is beyond the scope of this document, but we will present the options in more detail below...

(Alternatively, we can replace the NiCad battery and install either of the options below for you. Please use our "Circuit Board Repair" page to contact us regarding this.)

If you choose to replace the NiCad every few years, make sure you first remove it from the MPU / CPU board and mount the new battery away from any circuit boards. Attach some wires from the battery's positive and negative terminals to the positive and negative locations respectively on the board.

To replace the NiCad battery with 3 "AA" batteries, you will need to remove the original NiCad battery. Next, install a battery holder (away from the circuit boards) that can house 3 AA batteries. Wire the battery holder positive terminal to the "Anode" side of a diode and the "Cathode" (the end with the grey "band") to the positive location on the board. Wire the battery holder negative terminal directly to the negative location on the board.

To use a "Memory Capacitor" in place of the NiCad battery, you must first remove the battery and then solder the positive terminal of the capicitor to the positive location on the board. The negative terminal goes to the negative location on the board. There is no need to keep the Memory Capacitor away from the board. You must leave the machine on for around 8 hours to charge the capacitor, and then turn the machine on for a few hours every few weeks to keep it charged.

NiCad Batteries are used in:

A. Hankin and Co. ('78 - '80): Hankin MPU
Bally (late '76 - mid '89): AS-2518-17, AS-2518-35, AS-2518-133 & A084-91786-AH06 (6803)
Game Plan ('78 - '85): MPU-1 & MPU-2
Gottlieb (late '77 - late '89): System 1, System 80, System 80A & System 80B
Stern Electronics ('78 - '84): MPU-100 & MPU-200
Zaccaria ('78 - '87): Generation 1 & Generation 2

This is not a comprehensive list of pinball manufacturers that used NiCad batteries.

Button Cell Batteries

Button Cell batteries are only used by a couple of pinball manufacturers. Gottlieb was the first to use them with their "System 3" MPU / CPU boards in 1989. These batteries provide 3.0Vdc to the RAM IC, which stores the information needed to be saved when the power is lost.

It is not known exactly how long these batteries last when no power has been applied to the pinball machine, and it is also not really known how long it may take for one to leak it's battery acid.

As these batteries have only been used in pinballs since 1989, there are only a small amount of known MPU / CPU boards that have been affected by battery corrosion - ie: it is not a common occurance for battery corrosion on Gottlieb "System 3" or the Stern "S.A.M." circuit boards, as it is with other older MPU / CPU boards using the "Ni-Cad" or "AA" type of batteries (at the time of writing - mid 2008). That said, it DOES happen - even if it is only occasionaly.

So what does this mean to you? Keep an eye on the battery voltage, and make sure it does not drop below 2.5Vdc. Button Cell's have a tendancy to drop their voltage rapidly once they reach the end of their usefull life.

If you do need to replace one of these batteries, then make sure you use a battery holder to easily facilitate future replacements. Gottlieb used a battery that is soldered permently to the circuit board, so this will need to be removed, and a suitable battery holder installed.

Button Cell Batteries are used in:

Gottlieb (late '89 - '96): System 3
Stern Pinball, Inc. ('06 - current): S.A.M.