A Gottlieb System 3 game was turned off and on and then did nothing at all; the LED on the CPU board stayed dark.

System 3 game dead after a power cycle, CPU LED does nothing: bad F2 fuse holder

Cause: Power wasn't getting past the F2 fuse by the transformer because the fuse holder had failed, even though the fuse was there.

Checks

• Check that the coin door interlock isn't open.
• Measure on both sides of each fuse by the transformer, not just the fuse itself.
• Check the 5 V supply to the CPU.

Fix

• Replace the faulty fuse holder.

The transformer area carries line voltage. Unplug the game before working on fuse holders, and measure live only with care.

Systems

• Gottlieb System 3

Related tips

• Where the boards sit in a System 3 dot matrix backbox
• Game won't turn on with the coin door open
• Gottlieb System 3: voltage plug A12J5 wire colours

Source: Pinball Repair help group!! (Facebook group)