TCL LCD TV L32V10 three trouble-free maintenance examples - appliance repair - Database & Sql Blog Articles

DFN1006 TP-RCLAMP3321P ESD Diode Low Capacitance

Filter 18.432M

I recently repaired a 32-inch TCL LCD TV that had no display and no sound. After disassembling the unit, I identified the mainboard as model 40-A112C1-PWE1XG. During testing, I found that the fuse F1 (3.15A/250V) was blown. Further inspection of the PFC filter capacitor CE1 (450V/150UF) revealed a short in both polarities. Upon closer examination, I discovered that the backlight drive power transistors QW3 and QW4 (both 5N50) were damaged. After replacing these components and installing a new fuse, the TV still had no sound, which indicated that the motherboard was functioning properly. Therefore, the issue must be in the backlight circuit. I then checked the gate circuit of QW4 and the driver circuit. I found that resistor R506 (10Ω) was open, diode D502 (silkscreen A7W) had failed, and the backlight oscillator and driver IC OZ9976 (16-pin) was also damaged. Additionally, diodes D511 and D512 (silkscreen S4) were blown. The capacitor C512 was in good condition. I replaced all the faulty components: D511 and D512 with IN4148 diodes, D502 with two IN4148s, R506, and the OZ9976 IC. After reassembly, the TV worked perfectly.