The examples highlight common but critical issues we've encountered in failed repairs performed elsewhere. Our goal is not to criticize, but to educate and raise awareness.
The Mitsubishi examples shown here highlight where things went wrong, but just as importantly, they show what right looks like.
Incorrect component installed — part with 100µF instead of 33µF. Solder on the capacitor C14 exceeded the pad and created a bridge to inductor L1.
A failed repair, marked by a solder bridge, poor soldering, and the use of an incorrect capacitor, caused a catastrophic short and burned a portion of the circuit board.
Poor workmanship on the integrated circuit, all capacitors, and resistors. Excessive, cold joints, contamination, and filled vias. Wrong Zener diode installed.
Burn marks on the IC's third and fifth pins from the right. The excessive heat degraded the conformal coating, causing it to curl and blister.
Installed an incorrect opto-isolator in OI19. Two of OI18's leads are missing solder, creating a broken connection, and the solder pad was lifted from the circuit board, severing the connection between the component and the board's trace.
When you can recognize both failure and quality, you’re in a better position to make informed decisions, avoid costly mistakes, and choose partners who get it right the first time.
That’s the value, and the lesson, we hope this provides.
The authors, Brad Nieman, a Certified Electronics Technician (ISCET), and Dan Sharrow, a certified IPC Trainer, lead ICR, a team responsible for 11,000 repairs annually. ICR holds multiple certifications, including advanced through-hole and surface-mount soldering from Pace Worldwide.
