ArcadeShop Q*Bert high score kit no workie. Also, it's different than JROKs...

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ArcadeShop Q*Bert high score kit no workie. Also, it's different than JROKs...

I installed the Q*Bert high score save kit from ArcadeShop tonight and it doesn't work. When I turn the game on it freaks out with random sounds and odd graphics. If I pull the battery backed RAM out and replace it with the original RAM the game works again.

I was wondering if the method they describe of jumping the diode was incorrect or did I get bad RAM?

The AS kit says to remove diode D2 and replace it with the included jumper. Which, I did.

However, I noticed JROK outlined something quite different and here:

http://www.jrok.com/sohs/qb-upg.html

He shows placing a wire on D3 and running it as shown:

qb1.jpg


What do you think? Is arcade shops method of replacing D2 ok and I got bad RAM? Or should I try JROKs method? Or are they the same end result?
 
Ok, so I guess the method of jumping the diode is the same either way.

I checked my voltages and I was getting 4.9v. I adjusted to 5.0v on the main PCB and am still having issues.

I am guessing I got bad RAM because my original RAM works great and the game plays 100% with it.
 
Double check the date code on the RAM chip. IIRC, the internal batteries are good for 10 years. The last batch I got from Jameco were all older and didn't work.
 
Just an update to this...

The RAM arcadeshop sent me DID NOT work. So, I ordered some Dallas DS1220AD chips on Ebay and now it's working perfectly! At first it was corrupting scores so I replaced the caps on the main PCB (c27 and c25, 100uf@35v and 470uf@35v respectively). It appears to be working great now and it's saving scores.

Follow Jrok's instructions here if you want to do this yourself:

http://www.jrok.com/sohs/qb-upg.html

The RAM I got from Ebay is NOS but very old. So, it might just last for a couple of years or less. But, it's working now, so I am happy.
 
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The RAM I got from Ebay is NOS but very old. So, it might just last for a couple of years or less. But, it's working now, so I am happy.

The battery life starts the day the chip is first powered up.
If it is indeed NOS and has never been powered up, the battery should be ready to go for the rated years.
 
The battery life starts the day the chip is first powered up.
If it is indeed NOS and has never been powered up, the battery should be ready to go for the rated years.

Nope... The battery begins to power the ram when the chip is unpowered once the chip is first powered on...

The battery can still self-discharge before the chip is powered up... ever open a 'fresh' pack of 10 year old alkalines?
 
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