This time I found a Samsung 43UNUxxxx UHD 4K.......dead, Indicator not on
Check Psu by removing the cable to Mb.......NORMAL
Check the 3.3v stby tag on the remote sensor NOT PRESENT........wow if it's like this there's hope......hopefully it's just a dc-dc step down problem.
But it's also confusing .......which one is the 3.3v step-down......???
Check using an ohm meter 1x.
The 3.3v line is clearly not short......
Use an ohm meter, sorted starting from the TP 3.3v remote sensor......finally found the dc-dc step down......Check the dc-dc input 13v PRESENT..........Clearly dc-dc coit......grafted using universal......But the indicator light still doesn't turn on.
Use the ohm meter again........Check all the existing dc-dc OUTs (white cross marks).....
Oops....found one that is short???
Because I don't know how much the output voltage is......shoot it using 1.2v to be safe......Found C and it was scorching hot.
After C was removed. the output voltage was 5v and the stby indicator could light up. Normal success