hi as per my old thread lg 32lg46 totaly dead i have now managed to pick up a free 37 in version of this set the only problem is its missing its power supply but i have my old one out of the 32in thats shares the same psu unit EAY31845201/13 REV 1.2 now this board has only the 2 x 5 volts present ie st5v and st5v all other voltages are missing even using a 1k resistor as a load.a few members on here was helping me fault find on this board before the bridge rectifier decided to go pop this has now been replaced and the 2x5volts is back.i will copy and paste the advice and test point readings i have done from my old thread along with the pdfs and pictures i posted so you know how far we have got with the fault finding any help appreciated.
1. Since the PFC Voltage boost did not make the Voltage on the Main DC filter go up, Iwould like to contentrate onthe PFC circuts as hown in the PDF, Iwould like to get the P/N of the U800? and a good close up picture in the red area, there should be a switched transistor that is turn on to supply the VCC to the PFC IC when the PS_ON is present. Please see PDF. If I uderstand you correctly the DC voltage on the two large balck eletrolytics caps (450vdc rating) in the primary side stay at 340vdc with the TV on or off?
2. OK, I found the spec for the PFC IC P/N 5501A, we need to check the VCC pin
3. OK, looks like we are getting some where here, I will download your latest pictures and try to figure out where pin 8 of this U800 is connected to, it will not be easy since the board is not front of me to Ohm out the connection, you may have to do some probing for me.
budm was helping me test voltages etc right accros the capacitor as in your pdf test ponts its 13.8 volts across capacitor and between the other two test points its 2.4v
1. Since the PFC Voltage boost did not make the Voltage on the Main DC filter go up, Iwould like to contentrate onthe PFC circuts as hown in the PDF, Iwould like to get the P/N of the U800? and a good close up picture in the red area, there should be a switched transistor that is turn on to supply the VCC to the PFC IC when the PS_ON is present. Please see PDF. If I uderstand you correctly the DC voltage on the two large balck eletrolytics caps (450vdc rating) in the primary side stay at 340vdc with the TV on or off?
2. OK, I found the spec for the PFC IC P/N 5501A, we need to check the VCC pin
3. OK, looks like we are getting some where here, I will download your latest pictures and try to figure out where pin 8 of this U800 is connected to, it will not be easy since the board is not front of me to Ohm out the connection, you may have to do some probing for me.
budm was helping me test voltages etc right accros the capacitor as in your pdf test ponts its 13.8 volts across capacitor and between the other two test points its 2.4v
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