Hi guys picked this one up last weekend. Initially it presented as a dead set, after opening it up and verifying I had my standby voltage I powered it up with 2 1k resistors from Pson and BLon to standby, all power supply voltage within spec (12v, 3.5v and 20v).
Yet another lg main board failure...I started by checking all the voltage regulators on the main board, all had no voltage at all. So figuring the main processor wasnt sending out any signals to turn on the fets to power the main board I reflowed the main processor. After the reflow I now have the correct voltages leaving the regs (1.2, 1.5, 1.8) and now when you press the power button the light will change from solid red to a slow blink about every 2-3 seconds.
I downloaded the service manual and went down the testing checklist for the main board and everything tests good up to the X1001 crystal...as my frequency tester only goes to 10MHz Im not sure how to test it. The next item q8004 has 12v leaving, the lvds output I have not tested but the tcon is not receiving any voltage and the inverter control pin is still low .455v
I was hoping someone had delved deeply into one of these lg main boards and had a common failure point to check. I see a listing on ebay for this main board repair, so it would seem someone has figured it out. It sounds to me like it could be a corrupt eeprom but I think backlights would work with a bad eeprom.
Any ideas?
Yet another lg main board failure...I started by checking all the voltage regulators on the main board, all had no voltage at all. So figuring the main processor wasnt sending out any signals to turn on the fets to power the main board I reflowed the main processor. After the reflow I now have the correct voltages leaving the regs (1.2, 1.5, 1.8) and now when you press the power button the light will change from solid red to a slow blink about every 2-3 seconds.
I downloaded the service manual and went down the testing checklist for the main board and everything tests good up to the X1001 crystal...as my frequency tester only goes to 10MHz Im not sure how to test it. The next item q8004 has 12v leaving, the lvds output I have not tested but the tcon is not receiving any voltage and the inverter control pin is still low .455v
I was hoping someone had delved deeply into one of these lg main boards and had a common failure point to check. I see a listing on ebay for this main board repair, so it would seem someone has figured it out. It sounds to me like it could be a corrupt eeprom but I think backlights would work with a bad eeprom.
Any ideas?
Attached Files