Makita DC18RC charger dead? SMPS repair step by step

SMPS repair, step by step, on a completely dead Makita DC18RC charger: no LED, no response, nothing. One voltage reading on the primary side told the whole story. This DC18RC came in with zero signs of life, so instead of guessing I walked the SMPS from the mains input forward: bridge rectifier, bulk filter capacitor, switching stage. The filter cap read 1.1V where it should sit near 325V, and since the rectifier tested fine, the fault had to be between the two. It turned out to be a cracked solder joint on a power resistor, invisible until you know where to look. The fix takes seconds; the diagnosis is the part worth learning, and it applies to almost any switch mode power supply, not just battery chargers. Source of images : https://www.hackatronic.com/switch-mo... ⏱ CHAPTERS 00:00 A completely dead Makita DC18RC 00:39 Opening it up: first inspection 01:26 How a switch mode power supply works 02:33 Protections 03:15 Bridge rectifier and filter cap explained 04:59 MOSFET, transformer, secondary side 06:35 Testing the cord and protections 08:19 The thermistor trap: continuity vs resistance mode 11:03 Testing the bridge rectifier 12:52 Checking the MOSFET 13:18 Live measurements: 209V instead of 325V 14:38 Tracing the fault 17:45 Root cause 18:43 Reassembly and charge test 🛒 PARTS & TOOLS USED -Torx screwdriver bit - https://s.click.aliexpress.com/e/_c4b... -Soldering station : https://s.click.aliexpress.com/e/_c4C... -Soldering wire : https://s.click.aliexpress.com/e/_c4B... -Flux : https://s.click.aliexpress.com/e/_c32... -Multimeter - https://s.click.aliexpress.com/e/_c3d... #makita #dc18rc #chargerrepair #smpsrepair #electronicsrepair #toolrepair