Did you try clearing all the audits in the accounting section?
If not, just try hitting the "clear" button on the MPU board at each step of the self audit.

So far I haven't had to change dip switch settings to clear up garbage data on the displays.
The number of credits, high score to date, etc.. all need to be zeroed/ cleared with the button on the MPU as you step through each audit. Hopefully that's all you need to do.
If not, someone smarter than myself will be here to assist