Source: https://mokxi.com/learn/path/fault-finding-circuits Updated: 2026-11-11 All paths # Troubleshooting like a technician Find faults nobody planted for you: power first, half splitting, signal tracing, opens and shorts, failed parts and intermittents. Ends with a repair ticket: three boards, one fault each. Free 7 lessons 6 h 4 chapters 2,498 XP Electrical ยท Intermediate +150 XP 0 of 7 done Start the course free A method Lesson plan for teachers What you will build ## 3 projects, built step by step 7 lessons in 4 chapters, about 6 hours on a simulated breadboard. Free, in your browser, every step checked by the simulator. Chapter 1 project ### Half splitting Eight lights in series, all dark, one bad. Find it in three measurements instead of eight by always measuring in the middle of what is left. Open it in the simulator Chapter 2 project ### Opens and shorts A board with a dead short and an open on it. What each looks like on a meter: a short is zero volts and all the current, an open is all the voltage and no current. Find both and fix them. Open it in the simulator Chapter 3 project ### Intermittents Faults that come and go. Provoke a cracked joint with a tap test and repair it, then find a flicker that is not a bad part at all but a design with no margin, and fix the design. Open it in the simulator The map ## Chapter by chapter Each lesson opens when the one before it is done, and each chapter ends in a project. Chapter 1 ## Find it fast A method that works on anything, and halving the search with every reading. Open 200 XP ### A method A blinker that does nothing. Work it the way a technician does: symptom, power first, measure against what it should be, fix the cause, verify, and write it down. 0 of 6 steps Start What is in it Project Locked 498 XP ### Half splitting Eight lights in series, all dark, one bad. Find it in three measurements instead of eight by always measuring in the middle of what is left. 0 of 7 steps Chapter 2 ## Follow the signal Signal tracing, and what an open and a short look like on a meter. Locked 280 XP ### Signal tracing An amplifier with no output. Check its DC first, then follow the signal stage by stage from the source until it disappears, and replace the part where it died. 0 of 8 steps Project Locked 498 XP ### Opens and shorts A board with a dead short and an open on it. What each looks like on a meter: a short is zero volts and all the current, an open is all the voltage and no current. Find both and fix them. 0 of 7 steps Chapter 3 ## The hard ones Parts that are not what they say, and faults that come and go. Locked 280 XP ### Failed parts A transistor switch that will not switch. Read its junctions in circuit, then test the suspect and a spare out of circuit, and sort a drawer of parts that are not what their markings say. 0 of 8 steps Project Locked 462 XP ### Intermittents Faults that come and go. Provoke a cracked joint with a tap test and repair it, then find a flicker that is not a bad part at all but a design with no margin, and fix the design. 0 of 7 steps Chapter 4 ## Boss A repair ticket with three boards on it. Locked 280 XP ### Boss: repair three boards A repair ticket with three boards on it, one fault each: a supply putting out the wrong voltage, a blinker that only glows, and a driver whose LED never lights. Measure, fix, verify and write up all three. 0 of 8 steps Syllabus ## Every lesson in the course All 7 lessons, in order, each with what it covers. Any of them opens in the editor right away. Chapter 1 ### Find it fast - A method A blinker that does nothing. Work it the way a technician does: symptom, power first, measure against what it should be, fix the cause, verify, and write it down. - Half splitting Eight lights in series, all dark, one bad. Find it in three measurements instead of eight by always measuring in the middle of what is left. Chapter 2 ### Follow the signal - Signal tracing An amplifier with no output. Check its DC first, then follow the signal stage by stage from the source until it disappears, and replace the part where it died. - Opens and shorts A board with a dead short and an open on it. What each looks like on a meter: a short is zero volts and all the current, an open is all the voltage and no current. Find both and fix them. Chapter 3 ### The hard ones - Failed parts A transistor switch that will not switch. Read its junctions in circuit, then test the suspect and a spare out of circuit, and sort a drawer of parts that are not what their markings say. - Intermittents Faults that come and go. Provoke a cracked joint with a tap test and repair it, then find a flicker that is not a bad part at all but a design with no margin, and fix the design. Chapter 4 ### Boss - Boss: repair three boards A repair ticket with three boards on it, one fault each: a supply putting out the wrong voltage, a blinker that only glows, and a driver whose LED never lights. Measure, fix, verify and write up all three. Kits ## Build it on your bench too Every lesson runs in the simulator with nothing to buy. When you want the real thing, these kits have the parts. Have a kit already? ### Find your kit Pick the starter kit you own and run every lesson in its manual with the same parts on the same pins. See every kit Questions ## About Troubleshooting like a technician Is Troubleshooting like a technician free? Yes. All 7 lessons of Troubleshooting like a technician are free and run in your browser, with nothing to install and no parts to buy before you start. Do I need any parts? No. Every circuit is built on a simulated breadboard, and the simulator checks each step as you go. When you want to build it for real, the same parts and wiring work on a real bench. How long does Troubleshooting like a technician take? About 6 hours: 7 lessons in 4 chapters, each one a few short steps. Your progress is kept, so you can stop after any lesson and pick up where you left off. What will I build? Each chapter ends in a project that puts it together: Half splitting, Opens and shorts and Intermittents. Where do I start? With "A method", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.