For the Samsung washing machine, none of the LEDs are lighting up and the buttons are not functioning. Article source: Beijing Samsung Washing Machine Repair Phone Number http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3451922.
Fault Analysis: Based on the fault symptoms, there could be a problem with the power circuit.
Fault Inspection: The measurement of the 220V AC power supply voltage was normal. After checking with the Beijing Samsung Washing Machine After-sales Service Phone Number, it was found that the power fuse was intact. However, the power supply voltage for the microprocessor DJ2001 was measured at 0V, whereas it should be +5V during normal operation. This indicates an issue with the power supply circuit for the microprocessor DJ2001. The voltage across the rectifier filter capacitor C2 was measured as normal, confirming no abnormality in the rectifier filter circuit. However, there is a fault in the power adjustment transistor and its related circuits. After cutting off the power, relevant components such as V301, Z1, R1, V5, V6, and C4 were checked separately. It was found that the emitter of V301 was open-circuited and C4 had leakage, causing the abnormal power supply to the microprocessor DJ2001, leading to the described faults. After replacing V301 (D882) and C4 (100F/15V), the machine was tested, and the washing machine's spin-drying function returned to normal, resolving the fault.