With the coin door closed the flipper flies up as soon as the game is on or a game starts.

Flipper energizes and stays up at power-on or game start

Cause: A shorted TIP36 (power side) or hold TIP102 on the Fliptronics board; a shorted TIP36 usually slams the flipper up hard, a shorted TIP102 lifts it more slowly or not at all. Occasionally the Fliptronics U2 (74LS374).

Checks

• Test both the TIP36 and the TIP102; either or both can be bad.

Fix

• Replace the failed driver with its pre-driver and diode; then U2 if needed.

Systems

• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• Fliptronics flipper coil wired wrongly
• Fliptronics II board components
• How Fliptronic flipper drive works
• A coil or flasher energizes as soon as the game is turned on
• Where the WPC coil and lamp drivers sit
• The four groups of WPC coil outputs
• Electronic spares worth keeping for System 11 boards
• CPU and driver board transistors by position

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Two, Clay Harrell (pinrepair.com)