These materials are resources I recommend for learning more about retro video game electronics repair – I learned most of what I know from these guys!
Caius Arcade Repairs & Engineering
“How to fix arcade PCBs – A Beginners Guide” thread at the KLOV forums
Apocalypse Arcade Fixer Blog (defunct, but still available at Archive.org)
My Arcade Board Collection
I maintain a public list of my personal arcade board collection at http://www.arcade-museum.com/members/member_detail.php?member_id=477506