هانى النجار Professional Technician
عدد المساهمات : 937
نقاط : 2888
معدل التقيم : 0
تاريخ التسجيل : 14/11/2009
الموقع : EGYPT
|موضوع: Hisense LED40K16X3D, LED40K11P, LED40K16P, LED42T39AK الثلاثاء نوفمبر 22, 2016 3:37 pm|| |
LED40K16X3D, LED40K11P, LED40K16P, LED42T39AK, LED42K100, LED42K200, LED42K300, LED42H310, LED46K01P, LED46T39AK, LED37K01, LED37K11, LED37K16、LED50K660X3D, LED50EC660X3D, LED55T36GP, TLM37E29, TLM37V68, TLM37V88P, TLM40V66PK, TLM40V68P, TLM40V68PK, TLM40V69P, TLM42V67PK, TLM42V68PK, TLM42V86PK, TLM42P69GP, TLM42E58Pboard: (RSAG7.820.4162) 4162, 5024, 2289, 1673, 1185, 1901& etc LED TV Randomly Can’t Power On, Randomly Power Shutdown and Randomly No DisplaySymptom: The TV randomly can’t power on TV, or randomly power shutdown, or randomly no display, or when the TV long time in standby mode, it can’t use the remote controller to control power on TV. But power off the TV and then power on TV back, the remote controller can control the TV now.Cause: All these symptom are causing by the PFC voltage output drop below 370V, typically when occur the above symptoms their PFC output voltage is about 340V~ 360V or below 370V. What will cause the PFC output voltage drop? Actually they are many reasons, but in this case, it is because of their PFC IC pin-1 VFB (Voltage Feedback) sampling circuit line corresponding component/s leakage. Especially their voltage divider resistors are a common fault of this strange problem in TV power supply (PSU). It is because of these divider resistors leakages and it is causing by the red glue (Seal Glo) under these SMD resistor. For example the RSAG.7.820.1673 PSU board (normally call it as 1673 board), their divider resistors R823, R824 & R825 are inside the PFC section as photos below:Repair/Solution: Removed these divider resistors, cleaning their PCB board red glue and also the red glue attached on the bottom of SMD resistor. After clean all these red glue from the above divider resistors (R823, R824 & R825) and solder it back to their appropriate location. Finally this type of strange problems in LED TV was solved. Remember, not all the above PSU board their divider resistor is same these R823~R825, may be different part number of PSU board will vary. But their reason is same, is because of the PFC IC pin Voltage Feedback sampling circuit line component/s was leakage and caused these strange problem occur.