All the coin door buttons work except Begin Test, which still does nothing when its pins are jumpered right at the CPU connector. Some lamps may be acting up too.

Coin door Begin Test button does nothing: acid-broken trace on the CPU board

Cause: Old battery leakage had broken the copper trace on the CPU board between the connector pin and its input diode for the dedicated switch.

Checks

• Jumper the switch's pins at the CPU connector; if that does nothing, the fault is on the board.
• Follow the dedicated-switch input on the CPU from the connector pin through its diode toward the input chip, checking continuity at each point.

Fix

• Bridge the broken trace with a jumper wire on the back of the board.
• Clean and neutralise the battery corrosion on the board so other traces don't fail later.

Systems

• WPC DCS

Games

• World Cup Soccer

Related tips

• Won't boot after a ribbon cable was fitted one row off: unplug boards to find the damage
• Cleaning up alkaline battery leakage on a CPU board
• Changing the CPU batteries without losing settings
• Fitting a remote battery holder to a WPC CPU board
• Batteries get hot with the game on
• New batteries but still losing settings: test the holder
• Settings lost because battery voltage at the RAM is too low
• New batteries die in weeks or settings still lost: U8 RAM

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