Batteries on circuit boards has become a pet peeve (nightmare) of mine and I want to see everyone out there learn how to aleviate this problem. Games use batteries to keep high scores, bookkeeping and game setting in memory even when off or unplugged. Different manufactures use different styles. The early 80's method, borrowed from pinball design, was most commonly a rechargable ni-cad battery. The ni-cads worked well but over time they leak, corroding the solder and circuit board traces. Once the solder is corroded, desoldering becomes very difficult requiring considerably more heat to flow solder. Damage from the corrosion can quickly become a incurable cancer destroying the board beyond repair. Batteries, depending on style and usage, will leak in as little as 3 years. Most of the boards using these batteries are now more than 10 years old.

Battery Formats

AA Batteries - Common on Williams Games Defender -> Star Rider

Ni- Cads in several forms....

White or Orange AA sized battery - Common on Bally systems (Tron powers supplies), also . Pole Positions, early Taito games, Stern games (Berzerk, Frenzy).

 Blue AA sized but flat side batteries - seen on Taito systems

Brown or Yellow 1" long cylinders - Common on Asian bootleg boards

Black Nine Volt sized with 4 solder post - Common on Gottlieb boards

The point is no matter what type of battery is present get it off of the board now. Do not store these boards with batteries on them. Remove (rip) the batteries from the board and discard the battery. If there is any signs of corrosion, remove it. There is a running discusion on how best to do this (chemical dip, bead blasting etc), from my experience unless the corossion is minimal, you better start looking for another board because it will come back. (I usually use a wire brush and once the area is clean spray it with a clear polyurethane or lithium grease). Save us all the heartache and preserve those precious few boards left today. Quit reading this and get rid of you old batteries now!

Lithium batteries do not cause the same problems and I have yet to see a watch style battery corrode but I belive they will cause problems a few years down the road.

I have heard talk of games that had part of the program code in a ram chip that was backed up by battery. The idea being that if you removed the battery or the chip the board would not run again since the main program code would be lost. I have yet to run into these but I believe it is found in latter Capcom system boards (Buster Brothers?). It seems possible to me to extract the code from the rams and use roms instead. ** I have since heard that yes Buster Brothers needs to be powered up to help maintain the charge in the battery or it will die, same is true of Raiden II and The Shang Hai Kid (Memtron) and Springer.  Clay Cowgill has managed to defeat the Buster Brothers scheme.  I think I could defeat the Springer scheme if I had a working board to play with.

Boards with Nicads

Tron, Tapper, Spy Hunter, Domino Man, Wacko, Journey, Two Tigers, Satan's Hollow, Crater Raider, Disc of Tron?

Double AA batteries

Watch Style Batteries

Lithium AA Style Batteries

Excerpts from Newsgroup commentary.....

EXCELLENT idea to make frequent mention of those soldered-in time bombs. I would add Midway games like TRON with the battery on the Medium power supply board, OMEGA RACE on the mother board, and a few others I can't think of at the moment.

I would urge everyone to go look for batteries on their boards NOW and stop this senseless destruction!

Pinball people have reached a consesus on the proper fix for this problem being a remotely mounted battery holder. If and when the battery leaks in the future, the damage will be contained. For a typical 3.6 volt NiCad replacement, three AA batteries in series with a blocking diode are an excellent substitute in most applications. We even sell a ready made kit for this ($4.95). If you're building your own, put the diode on the + lead with the banded end facing the board.

Hope this helps save a board or two.

Marco Specialties, Inc. 5290 Platt Springs Rd Lexington SC 29073-9252 803-957-5500 FAX 803.957.6974

My only point to raise in this area is to locate the batteries at the BOTTOM of cabinet or headboard away from any boards. The potasium hydroxide vapour that leaks from both ni-cads and regular batteries is a base (NOT an acid) and is heavier than air. Thus any connections or pcb parts downwind tend to coorode first. Remember to wash with white(clear) vinegar to neutralize the base, then rinse with clean water, scrub and scrape at old corrosion, rinse with vinegar again, rinse with water, and blow dry. Make sure that IC sockets are OK and that feed through holes are looked at.

John's Jukes Ltd. 2343 Main St. Voice (604)872-5757 FAX 872-2010 Vancouver, BC, Canada V5T 3C9 (Pinballs, Jukes, Video Games)

I like the idea of using the M48Z0x series of chips. They're complete SRAM chips that will keep their contents for 10 years of power-off time (they have a lithium battery inside 'em). I used an M48Z08 to provide independent "CMOS" banks for all of the different games on my Williams hack board set. I'd love to figure out how to use one of these to replace the EEPROM on my Tempest boards (some day they're not gonna erase anymore... these NVRAM chips can be written as often as you like). It would probably require a software patch to tell the CPU not to check for erasure before writing. Nick Sayer 

Alternate idea would be to use a "super Cap" or super capacitor.  These are 1 F or even larger.  Jameco & others carry these.  The only down side to using a super cap to replace a NICAD is that the board/game must be powered up every 6 months or less to maintain a charge in the super cap.