Removing a soldered-in transistor or chip without lifting traces

Steps

• Clip the faulty part free of the board, leaving as much of each lead standing as you can.
• Hold one lead stub with needle-nose pliers, heat the stub (not the board) with the iron, and draw it out once the solder melts.
• Clear the leftover solder from each hole with a desoldering tool.
• Fit the new part with as little heat as will make a good joint; too much heat lifts or cracks traces, too little rips plated holes.
• When replacing a chip, solder in a good machine-pin socket first rather than the chip itself.

Systems

• Data East CPU Version 1/2
• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Related tips

• Finding a coil's driver transistor without a manual
• Which logic chips drive which solenoid transistor pairs
• Logic chips for the special solenoid transistor pairs
• Switch row trace map from CN10 to the 4011 chips
• The solenoid L/R select relay and transistor Q29
• Test EPROM flash codes: which chip failed
• Combining two-chip CPU code into one 27512 for 5C
• Bank select relay and CPU transistor Q29

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Two, Clay Harrell (pinrepair.com)