Holding the button makes the flipper chatter up and down.

Flipper machine-guns when the button is held

Cause: A broken hold winding in the flipper coil.

Checks

• Check the fine hold wire at its lug and measure the coil windings.

Fix

• Replace the flipper coil.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35

Related tips

• Flipper stays up after the button is released
• Flipper buzzes when held up
• Upper flipper weak and won't hold: second leaf switch on the lower flipper not touching
• Flipper won't kick but holds if lifted by hand: dirty or worn EOS switch
• Flipper weak, dead, or machine-gunning
• GI dims whenever the left flipper button is held: upper left flipper EOS not opening
• Small upper flipper fires repeatedly and drops: EOS contact tension
• Solenoid fuse blows when a flipper is used: worn spacer in the EOS switch stack

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)