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 fixing a Hisense 32-inch LCD TV model TLM32V68A that had been crashing occasionally.

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The issue was inconsistent: sometimes the TV would turn on but take a long time to boot, and other times, when switching channels, it would show a dense vertical line, no image, no sound, and both the remote control and panel buttons wouldn’t work. Occasionally, the TV wouldn’t power on at all, but the blue LED on the front panel would still be lit — which means the power is on, and the red light usually indicates off.

After disassembling the TV and doing a visual inspection, I didn’t see any swollen capacitors on the high-voltage board. The 12V and 5V power supplies were stable, so I suspected an issue with the motherboard. I checked the voltages on the motherboard and found that 5V and 3.3V were normal. However, when measuring the output of a three-terminal voltage regulator N6 (which should be around 1.2V), I noticed it was slightly higher than expected — about 1.29V.

The three-terminal regulator model is SE8117TA, which is an adjustable voltage regulator. But upon checking the circuit, I realized there was no proper voltage regulation between pins 1 and 2 — only a resistor connected directly to ground. Based on this, I replaced it with an AM1117 1.2V regulator. After the replacement, the temperature of the component dropped significantly, and the measured output voltage stabilized at 1.19V. After several power cycles, the TV worked without any crashes.

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The images above show the original faulty three-terminal regulator. It's clear how poor its performance was, leading to the instability in the TV. Replacing it fixed the problem, and now the TV runs smoothly again.

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