No picture or sound on model 49 LJ 550M

with no picture or sound on the tv, typically indicates either a bad main board or a failed power supply. to determine which, youll want to access the back of your tv and remove the cover to get to your boards. from there, you can take measurement s at the connector that leads to the mainboard from the power supply. with the set plugged in , but powered off….you should have standby voltage on the pin labeled stby. if this is there, and you power on the set, you should then get your 12v and 3.3v on the other pins of that connector. if these arent present, you can troubleshoot the power supply. if they are, the issue lies elsewhere. please upload some pics of the interconnecting of your boards for further assistance.

在已经存在的问题里加入图片.