Zero Power RAM Question

FrizzleFried

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Cruis'n Exotica uses a Zero Power RAM chip to save high scores. I have two PCB's here... the one in the cab would save high scores for an hour... a couple hours... perhaps a few hours, but turn off the cab, come back in a day or two... and they'd be gone. I then tried the chip on the other PCB. I was thrilled to see it would last a day... two days... three days... nice. Well, I've discovered the cut off is about a week to 10 days. Bottom line... high scores go bye bye after between 7 and 10 days.

QUESTIONS:

(1) How long should I expect a new Zero Power RAM chip to hold the info? A month? Two months? Year? Multiple years?

(2) I "assume" (you know what that means!) that this chip is re-charging while the power is on? Can anyone confirm this? If so, any idea how long I should run the machine monthly to maintain a nice solid charge?

Thanks!
 
Multiple years.

They do not recharge. They come in a couple of flavors - EEPROM style, FerroRAM style, and Lithium Battery style.

The type depends on the manufacturer. Most common: lithium battery style which is a very thick chip. They are supposed to last "up to 10 years." and may need to be replaced.
 
Thanks....

I'm surprised the're not on a trickle charge or something. I guess it doesn't matter how long I run the game each week/month. :)

The one on Exotica is a thick "chip" style... so i am guessing it's Lithium Battery style.
 
Yeah,

They are non-rechargeable battery backed SRAMs. The only thing holding the memory when the battery dies is any residual charge left in the memory cells after the power is removed. Some memory holds that for a long time without any help... even for days.

You can get replacements from Mouser.
 
Settings are keeping fine... my guess is it was replaced prior if it usually goes first.

Thanks!
 
OK ... so I buy a replacement ZeroPower chip from one of the Hong Kong distributors on ebay. It arrives... and I have verified by repeating this test 3x... but either the supposed NEW IC I received is bad... or something is wrong with my PCB.

If I power up the machine every couple days the high scores remain without issue....

If I do not power up the machine for 3 days... high scores gone. This is the same behavior exhibited in the other two ZeroPower IC's I have here (original one and one from the dead board I have)... but one of those would lose high scores if I didn't power up once a day and the other was about the same as this one... 3 days.

That tells me they sold me a bad/old IC... but I am no professional.

What is your opinion? Being it's ebay/paypal, I think I'm screwed and will have to ship a chip back to China to see my money back, right?

Also... anyone have a REPUTABLE source for one of these chips? I used cmosdevices on ebay... they have a 99.5% positive feedback with over 1800 transactions...

BTW - Evidently this is an old part as mouser shows no longer available. Anyone know a replacement part number by chance?
 
I got 3 of them from here http://www.ebay.com/itm/12092907876. They were fresh (8th week of 2012) and they all worked fine.

How can you tell how fresh an IC is?

Also... the chip I got did NOT have a notch on it to indicate direction. I inserted it the same direction (text-wise) as the old one. Be that good/bad/dumb.

EDIT: Also, your link goes to a dead auction... do you have the ebay name?
 
I do not know if the zero power RAM's in a Hard Drivin are the same or not. I replaced them in mine and ordered them from Mouser with this part number 511-M48Z0215PC1. There is a thread here about those chips relating to Hard Drivin if you choose to search for it.
 
I got 3 of them from here http://www.ebay.com/itm/12092907876. They were fresh (8th week of 2012) and they all worked fine.

Did you use those with Exoticas? They are a different part number than the one I took off the machine...

Which is:

M48Z128-85PM1

It doesn't have the same date code it seems as it says ODD1K005...
 
Slots... perhaps you (or someone else) can explain this behavior...

I get the new DALLAS ram (clicked the link a couple responses above)...

I install it and...

On power on... all the high scores were scrambled. That never happened before. No biggie... I reset high scores... all is good. I put up a few high scores... power down... upon powering up all new high scores are there... but the names are all 00000000 (just the new scores... not the stock ones). I just did a factory restore... put up a few high scores... power down... then up a minute later.... same thing... scores are all there but 000000 for names. ALSO, my keypad accounts aren't seeming to save (or they are being scrambled too).... when I attempt to use an account I made prior... it acted as if it was a new account.

I have not put the other chip back in to see if it goes back to the old behavior... but I will when I have time (dinner guests arriving shortly).
 
UPDATE: Had time to do a last bit of testing. Remove the DALLAS NVRAM and drop the old Zero Power RAM in and... back to normal. It will save high scores correctly...
 
Should I have gotten the -85's vs the -70+?

I have to admit I am a bit bummed. I've been waiting weeks for this chip to arrive.

:(
 
Remove the snaphat battery @U47 and the timekeeper ram at the same time and reinstall. See if that fixes the problem. I did have the high score table on one of mine corrupt. once I got it reset everything was fine. The -70 is just the speed. Faster speed should not be a problem.
 
I'm pretty bummed...

Pulled both chips. Let the game sit for a few hours (watching football). Just put both chips back in and...

Same thing.

Saves times fine, but replaces names with 0000000 ... this time though it also replaced all the "exotica" times with 000000 names... though it looked find upon first power up.... once I saved one score... powered down... then back up... 0000000...

:(

This is the 2nd chip I've bought via ebay to fix this issue. The first one simply did what the other two I have here do.... save find for a few days then I lose high scores. (same as the two original chips I have from two original boardsets... one lasts a day or two... one lasts a few days... the latest one I bought lasts a few days).

This DALLAS chip was my last hope.

:(

Would adjusting the voltage do anything to the HS circuit? It's just so odd it works fine with the other 3 chips (albeit for a short period of time unless I power up daily/every couple days).... and this one does what it does...
 
How is this for some crazy behavior...

I save a high score as "DAD"... power down... it comes up as 000000 upon power up. I then get a high score and save it as "DADROX"... check the high scores and not only is the current score I just saved say DADROX... but all the other scores that were saved as 000000 are now DADROX. Power down and back up... all say 000000 again... get another high score and call it "JON"... every score that was 000000 is now JON?!?1?
 
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