Ok, so you've decided to give up all that silly thimble collecting and start collecting 300 pound arcade games. Good for you! Now unlike thimbles, arcade games need a good bit of electronics know how to keep playing. The first thing you will probably encounter are dodgy monitors that wave, sync funny, or just look terrible. The good news is that a lot of problems (but not all) with monitors can be solved with a simple cap kit.
Below is a video where I explain the basics of discharging a monitor safely, and installing new capacitors. Most monitors contain (and most electronics for that matter) at least 12-20 "caps" which control certain voltage regulations in the monitor circuit. These dry out or die over time, especially if the game has been sitting in a dry warehouse for awhile. Some tips before we start...
Take your time
Double check your work before plugging anything back in
Mark the caps you replace with a Sharpie, to avoid confusion
Have a clean workspace, free of distractions
Have good lighting with your workspace
Invest in good tools, especially a decent soldering station
Clean as you go
Safety first always, if you don't know don't guess
... and finally if you really boffo something up, don't beat yourself up too badly. Everyone I have known in this hobby has a horror story about breaking something through a mistake. It's ok, but with the above tips you should be able to minimize those mistakes. And feel free to reach out to me at firstname.lastname@example.org with any issues.