just bought 3 flat screen tv's for 25 bucks

it depends on how many leds are in the panel and how much voltage each led uses. some panels use over 100vdc some 24v or less... so you are well in that range. but if one goes out, then none of them will work. i cannot find a schematic of your board, but if you can look up each part number for the led driver and test each value of the diodes/transistors or voltage regulators then you can get a better idea if your voltage is correct. if one component is not outputting the right measurement, then replace it. im almost certain you have a blown led though

heres what i would suggest you do:
test each led for continuity
if you find one thats bad, desolder and bridge its connection then reassemble tv and power on.
if you find all of them are good (after double checking ofcourse) then replace main board (make sure part number matches)

@neruve also, that 30v voltage could actually be to low which would indicate a failed component on the board that is in your tv your tv apparently has an "all in one" board which hosts the main/power supply ect). you could try to externally power each of the strings of leds as well. when you look at where the led leads hook into your main board, see if you see any values printed on the board itself. you may have to flip it over to see the values too.
 
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how many strips, how many leds per strip?

also how did you test them? did you set it to continuity/diode mode? my multimeter has continuity/diode mode in same setting. afaik you cant actually just continuity check the leds because they wont work until you supply some form of voltage to them. sorry for assuming your meter had diode mode. there is some other testing you can do though to check the leds. instead of explaining it, ill show you this video on youtube. you check each individual led by running current through it. 3 volts should be plenty of power to do the testing. you have to make sure to get the polarity correct as well, so if it dont work one way, flip your probes around and try again. if it doesnt work either way, then you have found your problem.

but those burnt marks could be a sign that something has failed on the tv's "all in one" board causing the leds to burn out. i have never seen any burnt leds as dark as the darkest one, though i have seen some that were a little discolored that did still work. so your best bet is to test each led itself.

[video=youtube;eEJoPCa7Kt0]https://www.youtube.com/watch?v=eEJoPCa7Kt0[/video]

tell me how many strips are in the tv and how many leds per strip.

also, can you take a picture of the back of the tv so i can get a better idea of what were working with here? detailed pics would be awesome ;D
 
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just fixed my 55" toshiba. turns out the power supply wasnt bad. i decided to recheck everything, and come to find out, the power on signal was reaching the main board from the power button, but not reaching the power supply to power on the secondary side. swapped main board ($45 part) and now i have a 55" toshiba LED muhahaha and about to go buy a 50" vizio smart tv for 50 bucks :/\:
 
So I can't get any of the leds in my screen to light with the 3v battery test you showed me. Starting to think maybe I should just toss it lol.
 
can you take a close up pic of your multimeter? if it has diode mode you can test them easily with that. if it dont work one way then flip polarity. i got a vizio for 50 bucks that is having problems with the leds as well. ill take some pics and post in the next few days. post close ups of your multimeter and post. ive never seen a tv that all the leds are shot, atleast one should be good. post good pics of your led strips as well.
 
No0bZiLLa said:
can you take a close up pic of your multimeter? if it has diode mode you can test them easily with that. if it dont work one way then flip polarity. i got a vizio for 50 bucks that is having problems with the leds as well. ill take some pics and post in the next few days. post close ups of your multimeter and post. ive never seen a tv that all the leds are shot, atleast one should be good. post good pics of your led strips as well.
Click to expand...

my multimeter does have a diode mode. Not quite sure how to use it though. Here are the requested pics. Its hard to get a picture of the whole strip at once. The scratch marks are where I scratched through the coating to test. Multimeter and strip pics
 
neruve said:
my multimeter does have a diode mode. Not quite sure how to use it though. Here are the requested pics. Its hard to get a picture of the whole strip at once. The scratch marks are where I scratched through the coating to test. Multimeter and strip pics
Click to expand...
yes, with it set to diode mode you should be able to power each led individually. in each position that you test, you may have to flip the probes around. the leds work on with a certain polarity (current will power them only one way not the other so flip probes). also make sure you have new batteries in multimeter. mine takes 9v and so should yours.
 
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