The roto-target turns only a position or two when hit, or hits don't score.

Roto-target spins only a number or two, or misses scores

Cause: Dirt (the roto is a form of stepper unit), or rivets not lined up with the contact fingers.

Checks

• A clean roto should spin about half a turn or more when flicked.

Fix

• Clean it like a stepper.
• Align the rivets with the target fingers so hits register.

Systems

• Electro-mechanical

Related tips

• Realigning a roto-target

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