I bought a few dead VFD games, and got them all back to work. Mostly the battery contacts are corroded, sometimes a PCB path is eaten away. Both easy fixes.
Remember that de Coleco's are not the best technically. Flimsy plastic and bad quality stickering make these table tops very hard to keep mint. Also I guess you need to remove the sticker to open it. Try find a Bandai Galaxian. OMG that one is AWESOME!