I just picked up a BBB, and don't know where the ram battery is located! I looked through the manual, and while it seems to mention the storage being protected with a battery, I couldn't see where that would be (I did my best to understand all the circuit board diagrams and their listed parts). Does anyone know where to point me in that regard? Thanks!

Answering for anyone else that might come across this question with no answer. Pic is attached showing where it is. There's more info here: http://www.robertwinter.com/pinball/bbb/forum/viewtopic.php?t=163&sid=b1748f2b431e519ce004cc974019af6a:

CPU Battery.
I hear alot of stuff about those batteries. Sometimes I read, "those batteries will last forever", and sometimes I read that the replacements are readily available (original and aftermarket). Fact is I never saw a CPU board needing one up until recently.

Now we all know batteries do not live forever. and we all know the damage leaking batteries can cause. So how did Capcom handle this? They use a "zeropower" RAM chip on the CPU board (instead of a remote mounted AA battery pack).

Essentially this is a 28 pin 6264 CMOS RAM chip with a battery mounted to the TOP of the chip. THE BATTERY IS NOT REPLACABLE! So when it dies, you just buy a new "zeropower" ram chip (which by the way, is NOT socketed!)

Zeropower RAMs will not be available forever. Really they are already obsolete (at least this style), and they have limited shelf life (that is, it's probably not a good to stock up on these RAMs and keep them forever). Since the battery is mounted right to the chip, it would be best to buy a fresh one when it's time for replacement.

The zeropower RAM's are still made by a couple companies and are available. They are widely used in the embedded controller market. There are two primary manufacturers: US company: Maxim (www.maxim-ic.com), French company: SGS Thomson (www.st.com)

The Maxim part is prefered by many (originator's of this battery built in part), but the ST part is easier to find. Both work equally well. For examples see the Mouser catalog.

Also Maxim makes these with a 'keep fresh' circuit (not sure about ST). As delivered from the factory, the battery is internally disconnected from the memory. As soon as you apply power to them for the first time, the battery is enabled permanently. This in theory gives them an unlimited shelf life if the part is never powered up. But it's still always best to install a "fresh one" instead of stocking up on these.

Another potential solution is to figure out a way to wire a remote AA battery holder, like so many of the other pinball companies use.

UNQUOTE

So i think, if this problem will, if ever, come into reality, it can be fixed.

I never had a problem with the battery with my Capcoms. But i also do not know anybody who had changed the battery one of the above mentioned ways.

IMG_4692 (resized).jpg

Another good quote to share: "The Capcom part in question (at least on the BBBs) is the ST M48Z08-100PC1. This is a non-timekeeping chip that has a 4.75V to 5.5V Vcc (which is permissible supply voltage). I see no reason why a 70ns part with a minimum Vcc of 4.5V wouldn’t work (but am no micro-electronics genius). If I am correct, then it seems that the M48Z58Y-70MH1 chip and M4Z28-BR00SH1 Snaphat would be suitable replacements if the originals start to go bad."