After One Hour LCD TV Display Abnormal
Model: Hisense TLM-4236P LCD TV Symptom: After an Hour, the TV Display Abnormal in all video inputs
Power on the TV, after about an hour, TV screen will show above photo symptom. Even try different video signals input like TV, AV and HDMI also same problem. So what will cause this TV display problem and how to troubleshoot it?
Regarding the photo symptom, it is looks like the Main board, LVDS cable, T-con board or the LCD Panel defective. Before that, checking all the PSU board outputs voltages are normal and stable. After that cleaning the LVDS cable contact pins with rubble eraser also no help. When the TV screen problem appears, try to call out the OSD Menu, the OSD Menu can show perfectly in the screen. That’s mean their T-con board and LCD Panel is ok. So the problem was in their Main board!
Checking all the Main board LDO and DC-DC circuits, their voltage outputs are normal and stable. For more details on how to troubleshoot the TV Main board, please refer to V4.0 LCD LED TV Repair Tips ebook. When the screen problem appears, checking the U12 DDR-RAM their Vcc voltage input has stable 2.5V. Also check the U41 Vcc inputs also normal and stable. Suddenly touch the U41 heat sink and feel that extremely hot! When use a plastic rod to pressing U41, the TV screen is back to normal! Even pressing the U12 DDR-RAM, the TV screen also back to normal too. When pressing other components, they are nothing happen or change on it. Just U41 and U12 when pressing it, the TV screen problem gone! So suspect the both of these components are dry join and causing the TV screen problem. Especially the U41, when it’s dry join it will causing their loading heavily and the IC power consumption will increase and generate more heat on the heat sink there.
After re-solder U41 and U12 both IC, testing this TV about 7 hours also no problem. Finally this TV screen problem solved!
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