Manuals
Most jukeboxes were created to withstand abuse. They were also created so the owner could fix what had been damaged or broken. Many manuals are around showing exactly how to fix these devices.
Replacement Parts
Because there were so many jukeboxes manufactured, there is a good secondary market for replacement parts. Websites, such as abjukeboxrepair.com, sell many replacement parts.
Tools Needed
The tools for jukebox repair are varied. Older models tend to just be off the shelf items that are used for playing records and making music. Most standard tools should work on those. However as the jukeboxes became more complicated, they began to require different types of tools, moving away from common screwdrivers to items such as hex and triangle screwdrivers. Finding these tools is easy. Auction sites such as Ebay.com sell them, as well as jukebox repair web-sites.