TCL 40s6500 tv restart faulty resistor fix guide
Recently, a TCL 40S6500 model TV came to our workshop with a peculiar issue. The TV would power on, show the logo briefly, and then restart immediately. This type of behavior often indicates a deeper issue within the TV’s internal components.
Upon receiving the TV, we opened the back cover to begin the diagnostic process. We first checked the voltages at various points on the main board to identify any irregularities.
Fault Diagnosis
After thoroughly testing, we discovered a voltage anomaly in one of the regulators on the main board. The voltage measured was significantly lower than expected. Where there should have been a stable 1 volt, we found only 0.650 volts. Based on this, we initially suspected the regulator IC to be the cause of the issue. We promptly replaced the IC and tested the TV again, but unfortunately, the fault persisted.
Further Investigation
Not satisfied with the initial solution, we decided to dive deeper into the issue. Our team checked the feedback section of the circuit and tested the resistors in that section. We discovered that one of the two feedback resistors was faulty. The two feedback resistors had values of 18k ohms and 13k ohms, and the 18k ohm resistor was damaged. This faulty resistor was preventing the correct voltage from passing through, which caused the TV to restart.
Software vs. Hardware
Generally, such faults are software-related, where a system restart occurs due to firmware issues. However, in this case, the problem was not related to the software but was rooted in a hardware fault. This highlights the importance of thorough diagnostics to identify the true cause of the issue.
Solution
Once we replaced the damaged 18k ohm resistor, the issue was resolved. After the replacement, we thoroughly tested the TV, and it began working flawlessly, with no further restarts or logo issues. The TV powered on normally and remained stable.
Fault Identification
Below is the image showing the faulty 18k ohm feedback resistor on the main board. This visual aid helps in understanding the issue better and shows how identifying the right component is key to resolving the fault.
Conclusion
This repair process highlights the importance of detailed fault-finding and diagnosis. Often, a TV may appear to have one issue, but further investigation may uncover a different root cause. In this case, replacing the faulty 18k ohm resistor restored the TV’s functionality completely. It is a reminder that taking the time for a comprehensive diagnostic check can save time and provide the best solution.
