TV REPAIROK made some progress.
Took the thing completely apart, LCD is gone, and it's sitting upright on itsedge because nowhere to lay it flat. If that damages it, too bad for him, I can't invent table space that I don't have...
So now I can see inside this thing and... uh oh.... where are the fucking LEDs, there are none ?!
Oh.. I see.... assumed somehow it must be lie the previous TV I fixed, that had an array of LED covering the entire chassis... well no, this newer TV has no array, it's lit only from the edge, and only one single edge at that !
Well, it that works, I guess why not...
So now we can see we have indeed 4 independent strings, and no resistor that I can see to equalize the currents between the strings that are //, so I guess no surprise that they blew eventually...
They cut the PCB in two. Eeach bit carries therefore two strings and a 4 pin connector. Each string carries 20 LEDs.
I immediately found a dead LED in the right half of the screen, the half that didn't work, so I was happy. Was easy to spot... it's was brown / cooked...
Buzzed it with the DMM because somehow '"at rest " they drop only 0.7V. I guess the typical 3V drop is only valid once they lit up and suck lots of current.
One has to scrape the white solder mask to reveal the copper so s to make contact with the DMM probes, but it's not too bad of a job.
So I could confirm that that LED was dead, open circuit. So I Widlerized it with side cutters, just because, then a BC558A agreed to sacrifice and donate one of its leads so I can use it to bridge the gap where an LED used to reside.
Then I plugged the TV to see what I get. Luckiiy the digital board is kind enough to accept to light up the screen even in the absence of the LCD panel...
NOw the strip with the dead / bridged LED lights up, yeah !!!
But... it's sister string, the last one to the right... does not. So I guess there must be at least one open circuit LED in that string as well.
Also, the first two strings / Left half of the screen, that used to work... well now one of the two strings is dead now !
So now instead of having the left half of the panel that light up, I have now alternating stripes of lights, as you can see.
OK... more work required.... but looks like I am making progress. I can't call it an "improvement " just now since it's one step forward and one backward, but I think at least I can call it " progress ", what do you think...
So now nee do a lot of scraping so I can test all the LED's in these two dead strips, and find the dead ones....
EDIT : well we did at least now prove that the power board / LED driver was indeed fine, which was still an hypothesis / educated guess just an hour ago.... so yeah, we did at least "improve" in the "diagnostics" department, short of improving in the "fixing" department just yet....