Hitting one METEOR drop target also scores another target in the bank, though hitting the other scores only itself. It still happens with the playfield switch plug jumped at the CPU.

One target also scores its neighbour: a stray switch jumper elsewhere

Cause: A previous owner had wired the start switch to a credit switch; that cross-connection tied two switch lines together.

Checks

• To find out whether a matrix short is on the board or in the game, unplug every switch connector, not just the playfield one.
• Look for added jumpers or rewired switches in the cabinet and coin door.

Fix

• Remove the jumper and restore the original switch wiring.

Systems

• Stern MPU-200

Games

• Meteor

Related tips

• One drop target only registers if it is the first one down: reseat and clean the PIAs
• Switch 3 shows closed and scoring goes haywire: check the coin switches
• Credit button does nothing in switch test: daisy-chained coin door wire come loose
• Drop target banks won't reset after new targets: springs too short and stiff
• Test a playfield switch diode

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