1.1 Basic Recognition Mnemonics
A circuit board can change in countless ways; the combination of components is key.
Resistors and capacitors are the most common; understanding their symbols is essential.
Resistance changes and capacitor leakage; remember the basic characteristics.
Inductance and voltage changes can be checked; measure the PN junction of transistors.
MOSFETs can be triggered and judged; distinguish between discrete and integrated components.
Analog operational amplifiers can be virtually shorted or opened; the quality of optocouplers varies greatly.
Digital devices are marked in front; measuring analog-to-digital conversion can be challenging.
ROM and CPLD programming are essential; CPU timing logic must be evaluated.
Sensors are prone to damage at the front end; knowing this helps avoid panic.
1.2 Tools and Materials Mnemonics
Prepare all repair tools; a small soldering iron tip should be fine and pointed.
Temperature should be adjustable with protection; ESD protection must not be neglected.
Fine-tipped tweezers are versatile; they can move, fix, and inspect thoroughly.
Use fine solder with flux; alcohol is essential for cleaning.
Flux increases fluidity; after soldering, clean up any residue.
1.3 Soldering Method Mnemonics
Prepare the pads before soldering; applying flux and tin makes it easier.
Use tweezers to gently place the chip; align it correctly without deviation.
Solder the diagonal pins first; secure the chip before further inspection.
Apply flux to keep pins moist; solder while the iron is in parallel.
Remove excess solder completely; ensure no short circuits remain.
Use tweezers to check for cold solder joints; clean with alcohol to remove flux.
Surface mount resistors and capacitors are easier; apply solder to one side and the component will stand.
Solder one end first and check alignment; then solder the other end to ensure it is straight.
1.4 Troubleshooting Mnemonics
The first step in repair is diagnosis; observe and measure to find the source of the problem.
Short circuit currents can be erratic; open circuit signals are hard to propagate.
Component damage can have many causes; overvoltage, overcurrent, and temperature can be detrimental.
Identify the fault point first; replace components without delay.
Reconnect any circuit issues; verify functionality after repairs.
Preventive measures are also crucial; ensure voltage and current are safe.
Regularly check temperatures; high-quality components extend lifespan.
1.5 Summary
This mnemonic covers the basics of circuit board repair, including recognition, tools and materials, soldering methods, troubleshooting, and preventive measures, aiding in the quick learning of circuit board repair knowledge. In practical learning and operation, combining these mnemonics with continuous practice will help better master repair skills.