When a new game is started the match coil energizes and stays on, and the tens and thousands reels reset to zero and then get kicked to 1. The doodle bug toy also only kept moving while the centre target was held.

Match unit fires and stays on at game start, reels kicked off zero: sticking slingshot

Cause: A rusty slingshot was not returning fully to its rest position, holding its switches in the wrong state during the reset sequence.

Checks

• With the game off, work each slingshot and kicker by hand and make sure the plunger springs fully back to rest.
• Look for any playfield mechanism whose switch is held closed at rest.

Fix

• Clean the rust off the slingshot mechanism (plunger, link and sleeve) so it returns freely, and re-gap its switches.

EM games run some circuits at line voltage; unplug the game before working under the playfield.

Systems

• Electro-mechanical

Games

• Doodle Bug

Related tips

• Game resets but no playfield solenoid works

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