What caused these wires inside our TV to turn into charcoal?
June 16, 2015 12:35 PM Subscribe
We just bought a Vizio E550VL LCD TV on Craigslist. We tested it before buying it, of course, and it worked fine; we brought it home and watched an episode of Game of Thrones on it, and it continued to work fine. The next morning when we turned it on, the screen brightness starting flickering badly, and a little while later the screen stopped turning on at all. When we opened it up we found this charred wiring (note blackened housing and brown spots on circuit board.) What should we do?
Obviously those jumper wires, and probably the boards they're attached to (the Slave 1 and Slave 2 inverter boards) will have to be replaced. But will that fix the underlying problem? Nothing else is obviously wrong with the electronics (no bad capacitors or anything like that) but it would suck if we spent $70 replacing parts only to have them fry again. Has anyone seen anything like this before and successfully fixed it? Where's the best place to buy parts for something like this, anyway?
(Bonus question: should we contact the Craigslist seller and ask for a partial refund? I don't see how he could have known about the problem, since there was no sign of it when we bought the TV, but the fact remains that we got all of four hours' use out of it before it quit on us.)
Obviously those jumper wires, and probably the boards they're attached to (the Slave 1 and Slave 2 inverter boards) will have to be replaced. But will that fix the underlying problem? Nothing else is obviously wrong with the electronics (no bad capacitors or anything like that) but it would suck if we spent $70 replacing parts only to have them fry again. Has anyone seen anything like this before and successfully fixed it? Where's the best place to buy parts for something like this, anyway?
(Bonus question: should we contact the Craigslist seller and ask for a partial refund? I don't see how he could have known about the problem, since there was no sign of it when we bought the TV, but the fact remains that we got all of four hours' use out of it before it quit on us.)
Best answer: That's the 2010 model, so it's 5 years old and has backlight circuitry using two or more CCFL tubes, not the more reliable (and lower power and voltage) LED backlight system that current LCD TVs use. Those CCFL tubes have a limited lifespan compared to the rest of the hardware. Looks to me like a tube finally blew and took its high-voltage power supply board with it.
posted by w0mbat at 12:59 PM on June 16, 2015 [3 favorites]
posted by w0mbat at 12:59 PM on June 16, 2015 [3 favorites]
Response by poster: Just want to note that the plastic housing a centimeter away from the circuit board was totally unmarked, so while this looks alarming it doesn't seem like it would have been much of a fire hazard.
w0mbat, that sounds plausible--is there a way to test that theory? Can we replace the CCFL tubes?
posted by fermion at 1:05 PM on June 16, 2015
w0mbat, that sounds plausible--is there a way to test that theory? Can we replace the CCFL tubes?
posted by fermion at 1:05 PM on June 16, 2015
I'm pretty sure that's the inverter board for the monitor bulb (or inverters). So that's like the one place where you expect high voltage to meet low voltage (i.e. where you have some CPUish thing that your remote talks to and the thing it controls).
Though, yeah, outside of having repaired a similar thing on my computer monitor recently, why IS that allowed without some fuse or whatever there to burn away instead?
posted by DeepSeaHaggis at 3:25 AM on June 17, 2015
Though, yeah, outside of having repaired a similar thing on my computer monitor recently, why IS that allowed without some fuse or whatever there to burn away instead?
posted by DeepSeaHaggis at 3:25 AM on June 17, 2015
Best answer: I've seen LCD inverters die in a blaze of glory like this before.
It might be a bad inverter, it might be a short in one of the ccfl tubes or somewhere upstream in the actual backlight module(s). Sometimes you replace the inverter board(s) and it works, sometimes you just toast another inverter almost instantly. Maybe it fucked up the tubes or something when it died and now you'll have a half dead backlight or a really dim one forever.
I would MAYBE try and fix it if i got a really cheap(like sub $30) lead on an entire inverter setup. Otherwise i'd just load the whole thing in the garbage, sigh, and head down your local "electronics surplus" type shady strip mall store on the outskirts of town and buy an LED lit model.
posted by emptythought at 4:16 AM on June 17, 2015
It might be a bad inverter, it might be a short in one of the ccfl tubes or somewhere upstream in the actual backlight module(s). Sometimes you replace the inverter board(s) and it works, sometimes you just toast another inverter almost instantly. Maybe it fucked up the tubes or something when it died and now you'll have a half dead backlight or a really dim one forever.
I would MAYBE try and fix it if i got a really cheap(like sub $30) lead on an entire inverter setup. Otherwise i'd just load the whole thing in the garbage, sigh, and head down your local "electronics surplus" type shady strip mall store on the outskirts of town and buy an LED lit model.
posted by emptythought at 4:16 AM on June 17, 2015
Response by poster: It looks like it would cost between $70 and $130 to replace the boards (depending on if we only have to replace the ones that are obviously broken or if we have to replace all of them.)
We'll get in touch with Vizio and see if we can shame them into helping us out by pointing out the fire hazard potential, although I expect that's a long shot. Thanks for all your expertise.
posted by fermion at 4:27 PM on June 17, 2015
We'll get in touch with Vizio and see if we can shame them into helping us out by pointing out the fire hazard potential, although I expect that's a long shot. Thanks for all your expertise.
posted by fermion at 4:27 PM on June 17, 2015
As an anecdata point, my friend just bought a very very very nice NEC "professional display" 47in LCD at one of those aforementioned surplus shops for $120. It has amazing picture quality and looks cool.
The shop had a stack of them.
The other shop i went to a while ago had sonys. I bought one for... $125.
This thing is probably not even worth the cost of parts. Time to explore some seedy strip malls.
posted by emptythought at 4:35 PM on June 17, 2015
The shop had a stack of them.
The other shop i went to a while ago had sonys. I bought one for... $125.
This thing is probably not even worth the cost of parts. Time to explore some seedy strip malls.
posted by emptythought at 4:35 PM on June 17, 2015
Response by poster: emptythought, that is a good idea. Any chance you could suggest some electronics surplus stores in the Seattle area? I don't have a car, so I don't get out to the Strip Mall Regions as often as I otherwise might.
posted by fermion at 12:01 PM on June 19, 2015
posted by fermion at 12:01 PM on June 19, 2015
Response by poster: Update: We tried talking to Vizio (leaning on the 'fire hazard' angle a bit) but they were zero help. My partner found the inverter boards for ~$30 each on eBay; I was pretty pessimistic about our chances, but we installed them and...the TV works! So far, anyway. We will be careful not to leave it powered up when we are out of the house. :)
posted by fermion at 3:50 PM on July 14, 2015
posted by fermion at 3:50 PM on July 14, 2015
This thread is closed to new comments.
Also, the way that thing failed looks scary. If you do opt to try repairing it, I would be very careful not to leave the room with it on and to unplug it from power completely when not in use.
posted by contraption at 12:43 PM on June 16, 2015