Big Bang Bar

[BBB94]

I thought I remembered a topic from the old forum about how the Capcom boards have a chip that has an integrated lithium battery or something and that once activated the chip has a limited lifespan.

Assuming I'm not not crazy and/or totally mis-remembering things (both very real possibilities), could the knowledgable folks out there cover the topic again?

P.S. I am moving foward on the merchandise in the background and will have more info in the coming weeks, when I have more time and answers.

[Bertl]

Marvin says:

QUOTE:

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.

Brgds
Norbert

[BBB94]

Thanks Bertl!

Can someone shed some light on who made the original component in question and what the part number is? Do we know if the chip performs a timekeeping/clock function?
---
It looks like if these parts ever start to fail that we may be able to replace them with a version where the battery is changeable. It appears that there are one or more chips that come in a SOIC (a/k/a SOH) configuration, which allows for a snap-on battery called a Snaphat, part number M4Z28-BR00SH1. Not to be confused with the Caphat which is the one piece version.

If they do not perform timekeeping, then the replacement part is probably either the ST M48Z08 or ST M48Z18 (which has a lower minimum Vcc – whatever that means). Both are 100ns. ST’s literature asserts that a Snaphat version is NOT available for these, however Mouser indicates that there is an SOH version of this chip.
http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=331160&e_categoryid=245&e_pcodeid=51160

Based on the below spec sheets:
http://www.st.com/stonline/products/literature/ds/2424/m48z18.pdf
http://www.st.com/stonline/products/literature/ds/2559/m48z58y.pdf
It appears to me that the ST M48Z58 or ST M48Z58Y might also work as they seem to be functionally the same as the 08 and 18, just faster at 70ns. These definitely come in a Snaphat version.

If the chip performs timekeeping, then the part numbers are M48T08Y or M48T58Y. The Snapcap is M4T28-BR12SH1 (which has a battery and a crystal).
http://www.st.com/stonline/products/literature/ds/2411/m48t08y.pdf
http://www.st.com/stonline/products/literature/ds/2412/m48t58y.pdf

The best searches for Mouser.com are “zeropower 64k”, “snaphat” & “timekeeper 64k”.

[BigBangJoe]

That's way too complex for my feeble brain, but if someone ever finds a suitable (and modern) replacement part, then I certainly want to know about it

[BBB94]

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.

Perhaps I will try to find a M48Z08-100PC1 to dissect to determine if the battery is truly un-replaceable and/or if there is another way to power the chip. It might be nice to have the option of cutting or drilling a couple holes in the existing chip to attach a new battery, than to have to de-solder and re-solder a new chip onto the circuit board.

[kirklake13]

So has anyone actually replaced this chip with the battery? If so did it fix the loss of HS problem? I have obtained an NOS CPU from Kerry, is the chip in question on the CPU? Will replacing the whole board also fix the issue of losing HS? or tis that questionable too?

captkirk
BBB#78
_________________
BBB #102

[BBB94]

I'm surprised we haven't heard of these batteries starting to fail. I thought they had an expected life of 10 years. The boards were likely close to 10 years old in 2006. Now they are over 15 years old.

I never did get around to experimenting on the chip repairs or replacement.

Some information can be found here:

http://www.pinrepair.com/capcom/