Hisense LCD TV TLM32V68A irregular timing failure repair - appliance repair - Huaqiang Electronic Network

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I haven't posted in a while, and I had nothing to do today, so I decided to share my experience with a Hisense 32-inch LCD TV model TLM32V68A that recently crashed. The issue started with inconsistent behavior — sometimes it would turn on but took a long time to boot. Other times, when switching channels, the screen would show a dense vertical bar, and there was no image or sound. The remote control and panel buttons also stopped working. In some cases, the TV wouldn't turn on at all, though the blue LED on the front panel would still be lit (the blue light indicates power is on, while red means off).

After disassembling the unit and visually inspecting the capacitors on the high-voltage board, I found no bulges or obvious damage. I checked the power supply voltages and they seemed normal: 12V and 5V were stable. However, I suspected an issue with the motherboard. When measuring the voltage near the microcontroller, specifically the three-terminal regulator N6, I noticed it was slightly higher than expected. A direct measurement showed 1.29V instead of the expected 1.2V. The regulator model is SE8117TA, which is an adjustable three-terminal IC, but the circuit didn’t have a proper voltage divider between pins 1 and 2. Instead, pin 1 was directly connected to ground through a resistor.

Based on this analysis, I replaced the faulty regulator with an AM1117 1.2V three-terminal IC. After the replacement, the temperature of the component dropped significantly, and the output voltage at pin 2 stabilized at 1.19V. I tested the TV multiple times by turning it on and off, and it worked without any issues afterward. The problem seems resolved, but I'll keep monitoring it for a few more days to make sure everything stays stable.

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The images above show the original poor-performing three-terminal regulator IC before replacement.

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