On the first two days, a 46-inch "RCA" LCD TV was delivered. The model number is L46FHD37Ryx7. According to the customer's explanation, after watching the TV for more than two hours, it suddenly went completely black and emitted a slight burning smell. I suspected that some components inside might have been damaged, so I didn’t power it on for testing. However, the customer was in a hurry to use the TV, as there was a game scheduled that day. So I offered him a $218 repair quote, with an inspection fee of $45. He agreed, and we arranged for him to pick it up later that afternoon.
After opening the back cover, I immediately checked the power board. Without any prior diagnosis, I found a burned-through MIT-SH-105LM relay, a charred 5W 2R2J resistor, and a blown 16V 1000uF electrolytic capacitor (Cs19). To my surprise, the fuse was still intact.
Following the basic principle of easy before difficult, I decided to replace the board to prevent the issue from recurring. I connected an 110V 150W bulb in series with the fuse and tested the power board. The 5VSB voltage was unstable, showing pulses with an amplitude of 3–5V. After a moment’s thought, I suspected a faulty capacitor. I traced the 5VSB line and checked each capacitor one by one. When I reached the VIPer22A-K6V918 IC, specifically the 4th pin, and checked the filter capacitor C2I (50V 10uF), the pulsation disappeared immediately. I replaced the capacitor, and the TV powered on without any issues.
In the afternoon, the customer came to pick it up, and I confirmed everything was working fine. He was very happy and even gave me a $20 bonus! It felt great to solve the problem quickly and efficiently.
Here are some photos of the process and the repaired components: Leakage protector, also known as leakage switch, is a new type of electrical safety device, mainly used for: ZHEJIANG QIANNA ELECTRIC CO.,LTD , https://www.traner-elec.com
(1) Prevent electric shock accidents caused by electrical equipment and electrical circuit leakage;
(2) Preventing single-phase electric shock accidents during electricity use
(3) Timely cut off single-phase grounding faults in the operation of electrical equipment to prevent fire accidents caused by leakage
(4) With the improvement of people's living standards and the continuous increase of household appliances, personal electric shock and fire accidents caused by defects, improper use, and inadequate safety measures of electrical equipment in the process of using electricity have brought undue damage to people's lives and property. The emergence of leakage protectors provides reliable and effective technical means for preventing various accidents, timely cutting off power, and protecting equipment and personal safety.
The leakage protector should meet the following technical requirements
(1) The sensitivity of electric shock protection should be correct and reasonable, and the starting current should generally be within the range of 15-30 milliamperes
(2) The action time of electric shock protection should generally not exceed 0.1 seconds
(3) The protector should be equipped with necessary monitoring equipment to prevent it from losing its protective effect when the operating state changes. For example, for voltage type electric shock protectors, a neutral grounding device should be installed.