Have you got "garbage" on your dot matrix display? Try reseating the ribbon cables in the backbox - be careful to make sure you line all pins up correctly. Do this a few times to clean the pins.
Welcome to Pinballchat! I will be posting here regularly about pinball machines, with information about pinball machines I own, personal reviews of pinball machines, pinball machine repair tips, pinball machine game play tips, how to care for your pinball machine and any other pinball machine related subjects that take my fancy! If you have any pinball related questions please email the PinStig at pinballchat@hotmail.co.uk and I will do my best to answer your questions on this blog.