Williams Stargate Rom error

[jb6626]

I have a williams stargate that i picked up not working.  After sorting through typical power supply problems (replaced with modern switching power supply) the machine worked perfectly.  After about 2 weeks it can no longer save high scores (even with new batteries on board) and the programmed high scores are not right and the letters are a jumbled and full of random characters.  When in the test/adjustment mode i cannot adjust game modes (adjust bonus amounts, free play, ect.) the machine will not accept them.  It gives me a CMOS Ram error or write protect failure.  I am hoping someone can tell me which chip is offending or where i should start pulling and cleaning.

[SirPeale]

Try this: pull the battery (you did modify the board to take a single CR2032 battery, right?  ) wait five minutes and turn on the machine.  Go into setup and set things up as normal.  Leave the machine running and insert the battery.  Sometimes the data becomes corrupt and needs to be reset.

[jb6626]

I have not modified the battery yet because I don't change things that are not problems until I have made the machine work 100% so as not to create other problems during diaognostic period.  Once I am satisfied with proper operation I will update the battery.  I have included a screenshot of the high score screen so you can see what it is doing.  I removed the batteries (the battery holder was cleaned and checked for proper contact) let the machine set and restarted and the machine and the condition is the same.  I have one of the few machines that was stored without batteries -- no acid damage.