Finding and Replacing the Batteries

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To access the batteries, turn off and unplug the game, and unlock the backbox and carefully remove the translite or backglass. If the batteries are removed while the game is off, all the settings and high scores will be lost. It is possible to replace these batteries with the power turned back on, but this should be attempted only by qualified personnel. Note that several hundred volts are present on the surrounding boards below.

See the caution at the beginning of this website. Do not attempt to replace batteries with the power on if you are not qualified. The voltages present are potentially lethal.

Bally Battery Location
The location of the batteries in a Bally pinball machine from the late 70’s to the mid- 80’s. These batteries are located in the back box, behind the translite or backglass. Originally, there was a nicad battery located here. If it is still there, it likely has leaked and damaged the circuit board. In this machine, the battery has been replaced with a high capacity capacitor and it will never need to be replaced.
Close up of battery
A close up of the capacitor used to replace the batteries. A capacitor like this may be used in any of the machines. Capacitors work by storing a charge when the machine is on. If the machine is left off for a long period of time (months?), the memory can be lost. Capacitors do not leak like batteries and cannot damage the circuit board.
WPC AA Batteries
The best way to avoid damage from leaking batteries is to not have any. Find out how to get rid of those AA batteries here.

This is the location of the batteries in Bally / Williams games (WPC) manufactured in the 90’s. If these batteries leak, they will damage the circuit board, usually below the batteries. Once this circuit board is damaged, it may become unusable. Change these batteries at least annually. Batteries in Williams System 11, plus Sega/DE/Stern games are in a similar holder. Newer Stern games do not use AA batteries but use coin / watch batteries. They do not need to be replaced on a regular basis since they rarely leak.

To access these batteries, it is necessary to unlock the backbox and remove the translite. On some models, it may be easier to remove the display / speakers below the translite and carefully place it, display down, on the railings of the playfield.

If the batteries are removed while the game is off, all the settings and high scores will be lost. It is possible to replace these batteries with the power turned on, but this should be attempted only by qualified personnel. If the display is also removed and placed display down on the railings of the playfield, be certain that no wires or circuit boards short or make contact. Several hundred volts are present on the display. See the caution at the beginning of this article.

Some hobbyists remove these batteries and place them in a separate battery pack located elsewhere, usually below the circuit boards in the backbox. This protects the circuitry in case the batteries should leak.

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.

Note that it is a good idea to go into the service menu and write down all the settings on a piece of paper. That way, in case memory is lost, it is possible to return your pin to the settings you are used to. Store that piece of paper with your settings in the user manual.


Comments, including suggestions, improvements, errors, etc. are welcome (see below).

If you have a specific question about your game that does not directly apply to batteries, please see our FAQ section.

12 thoughts on “Finding and Replacing the Batteries”

    1. We never use rechargeable batteries in games. In games that normally use AA batteries (or coin watch type), there is a diode that prevents the batteries from being charged. Plus rechargeable batteries need to be carefully recharged. Lithium batteries could overheat and catch fire if not properly charged.

      Older games, such as early Bally and Stern used rechargeable batteries. If that is replaced with a memory capacitor, then that acts as a rechargeable battery.

    1. That is a newer Stern S.A.M system. Those games should have a ‘coin’ or ‘watch’ battery on the CPU board. They tend to last ~5 years although one of ours is on the 7th (and should be changed!).
      The CPU has a CR2430 lithium coin cell battery.
      The replacement procedure will be in your manual. If you don’t have a copy, download it from Stern. Some of these manuals are located on the IPDB too.
      Generally, you should change this battery with the power on and the machine booted in order to not lose the memory and settings in your game.

  1. What I can never get my mind around is why Williams used an Analog power supply and stuck with it to the very end of their existence. The second thing was why the NVRam which was available for things like TV sets since the early 90’s were not adopted into the MPUs map. Finally I was always puzzled at why the Relay that switched the GI was put on the power supply pcb, they had it right originally with that off the board.

    1. A good question Allan. We do not know the answer to this. And it was not just Williams, but also Gottlieb, plus Data East / Sega / Stern.
      It continues today. Stern pinball machines have ‘coin cell’ batteries that need to be changed every ~5 years. Jersey Jack Pinball uses fairly common computers and they have the mother board lithium batteries that require replacement.

      We are guessing, but some of it might be cost. But another practice benefit of not using NVRAM is that NVRAM cannot support clocks. For home users, having a clock might be of little benefit. But commercial operators use the clocks / date for keeping track of income and other functions.

      To the manufacturers, having battery leakage was not expected to be much of an issue since pinball machines were not expected to be in use longer than a few years. Of course, that has changed.

      Aftermarket boards for Williams WPC sometimes have coin cells, sometimes remote battery packs (which we dislike) and sometimes NVRAM. We recommend buying aftermarket boards that use NVRAM. However, we are currently dealing with an issue with a new aftermarket board that has NVRAM and will not save the settings.

  2. Claude, hi guys,I have a Williams Flash pinball and when I turn it on, all the lights turn on and nothing else happens. That is my problem.
    Anybody having a solution would be appreciated.

    1. Hi Claude.

      Unfortunately, there are a ton of things that could be causing this. We always recommend starting by measuring voltages (caution, deadly voltage is present – only do this if you are qualified).

      If those voltages are OK, there are several other things to look into. The problem with this generation of Williams pins is that line of ‘interconnects’ between the upper board (MPU) and the lower board (driver) on the left side. If just the right one is not making contact, it will not boot. Sometimes unplugging and plugging the two into each other will fix that for a while. In the long run, that plug – both halves – should be replaced.

      Other times, it is the sockets that house the ICs.

      And all of this assumes that the batteries have not leaked and ruined the board.

      This type of troubleshooting requires a lot of testing and work. If you are not experienced, we would suggest contacting one of the people on The Pinball Repair Group who fixes these boards. Eugene Mosh is one of several who has a great reputation.

      If your voltages are good, you could also buy a new board – but those are expensive.

  3. I have a Mandalorian Premium and a Ninja Turtles Pro. Both very new Stern titles. I couldn’t find AA or coin cell batteries in either one of them.

    1. A good question. We have not had to replace one yet. There isn’t information in the manual in the table of contents. And there isn’t an index in our manual. Towards there middle of the main board in the backbox, there is a plug with two wires – one red and one black. Directly below that are a few cylinder capacitors. To the right in the coin cell battery. It is not flat but held on its edge, so it is easy to miss.

      Normally, we would change it with the power on. But we don’t have any experience doing this yet and given the history of SPIKE circuit boards being sensitive, I would call Stern and ask them. Let us know what you find out. If we find anything out, we will update the page with the information.

      Thanks for bringing this up.

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