IC and processor pins
You're at an IC on a board: which pin is which, what should you measure where, what should the scope show, and what does a wrong reading mean? Learn by tapping the chip drawing.
SMPS and PWM controller ICs
UC3842 / UC3843 pins: what to measure, what to see
Flyback adapters, monitor and printer supplies, older TV standby circuits
🔒 repair packTL431 pins: what to measure in the feedback loop
The feedback circuit of chargers, adapters, TV and PC power supplies
🔒 repair packL6562 pins: what to measure on a PFC controller
LED TV power boards, PC power supplies, adapters over 75 W (equivalents: L6561, NCP1608, FAN7930)
🔒 repair packL6599 pins: what to measure on an LLC controller
LED TV main supplies, PC power supplies, LED lighting drivers (equivalents: L6599A, NCP1396, FAN7621)
🔒 repair packPC817 pins: how to test an optocoupler
Almost every charger, adapter, TV and PC power supply (equivalents: EL817, LTV817, FOD817)
🔒 repair packTL494 / KA7500 pins: what to measure in a PC supply
ATX PC power supplies, inverters, UPSs (equivalents: KA7500, DBL494, MB3759)
🔒 repair packSG3525 pins: what to measure in an inverter
Battery inverters (12/24 V → 230 V), push-pull DC-DC, welders (equivalents: KA3525, similar to SG3524)
🔒 repair packVIPer22A pins: an SMPS IC with the MOSFET inside
Small adapters, satellite receivers, standby supplies of appliance and air-con boards (family: VIPer12A, VIPer22A, VIPer53)
Drivers, timers, op-amps and regulators
IR2110 pins: a half-bridge gate driver
Inverters, motor drives, welders, class-D amplifiers (similar: IR2113, IR2104, IR2184)
🔒 repair packNE555 pins: what to measure on a timer
Flashers, timers, alarm circuits, simple PWM and motor speed control
🔒 repair packLM358 pins: a dual op-amp
Battery chargers, sensor boards, current sensing, simple amplifiers (similar: LM2904, the quad LM324)
🔒 repair pack7805 pins: a 5 V regulator
The 5 V supply of almost every board (family: 7805, 7809, 7812, 7815; negative: 79xx)
🔒 repair packLM317 pins: an adjustable regulator
Adjustable bench supplies, charging circuits, LED constant-current drivers
Processors and memories
24C64 pins: an I2C EEPROM and WP write protection
TV and monitor mainboards, car dashboards, printers, routers, boiler boards (family: 24C02, 24C04, 24C08, 24C16, 24C32, 24C64, 24C128, 24C256; 24LC64, AT24C64 and M24C64 share the same pinout)
🔒 repair packATmega328P pins: what to measure on a processor board
Arduino Uno and similar boards; the same logic applies to any microcontroller