All playfield or backbox lamps are out, no coils work, or the game will not power on, though the fuse tests good.

No lamps, no coils or no power: tired fuse holder

Cause: The fuse clips have lost their spring or are dirty, giving a poor connection. Dirt adds resistance and heat that can blow the fuse. Very common on Bally, whose fuse blocks also crack.

Checks

• Look for cracked fuse blocks and loose clips.
• Clean the clips and fuse caps.

Fix

• Bend the clip tabs for tighter grip (they can snap).
• Replace broken or cracked holders or fuse blocks.

Unplug the game before touching the line fuse holder.

Systems

• Electro-mechanical

Related tips

• Check fuse ratings before the first power-up
• Fuses to keep for EM games
• Where EM fuses are
• Game tilts mid-ball, then won't power up: cold solder joints on the fuse block
• All lights out but the fuse is good

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part One, Clay Harrell (pinrepair.com)