Vizio E470VL backlight shutting down

[Taterbug]

Re: Vizio E470VL backlight shutting down

The resistor was in line with the Mosfets that blew. I also had a 12volt smd regulator that it took out. Looking for a replacement for that now....Just had to order SMD regulator
4415GH. Guess I will set this one aside until the parts get here and go back to work on the 43" samsung...

[Taterbug]

Re: Vizio E470VL backlight shutting down

OK, I replaced the regulator and have all my voltages except THE HIGH VOLTAGE. It is like the regulators are not turning on. I monitor the PS-on voltage along with Lamp and Inverter on signals and they are all their when I use the remote to turn on the TV. I am getting a white Vizio Light but it just stays white no pic at all. I wonder if one of the K3568's I replaced was bad? I pulled them off an old board from a different brand TV but they read good with an ohm meter???

[Taterbug]

Re: Vizio E470VL backlight shutting down

Replaced entire power supply board and back to the original problem. Got an eprom on order. Gonna replace it next.

[Taterbug]

Re: Vizio E470VL backlight shutting down

Ok, I ordered a new eprom and the instructions said it was U14 underneath the can. There was not a U14 but a U12. I replaced U12 but now I think I made a mistake. I saw another picture on the web that showed the chip was U15 on the back of the Board. Here is my board number 3647-0292-0150(3J) and 0171-2272-3253. Which chip is the eprom for this board? Also does anyone know of a source for the entire board incase I just want to order a new board. Everywhere I have checked is out of stock for this board. Thanks

[ecking767]

Re: Vizio E470VL backlight shutting down

The eeprom is located on the back side of the board U15, It will help to post picture of your main board.

[Taterbug]

Re: Vizio E470VL backlight shutting down

OK I found the eprom I will post a photo and it is circled in red. Thanks for the help. I have a new one on order and fortunatly kept the old chip i removed from the top of he board. The eprom I had ordered previously from ebay had cheap, cheap legs and they broke off. That is why I had to order a new one. Hopefully this will fix the problem. I was thinking about replacing the entire board but everyone on the web is out of stock.

[Taterbug]

Re: Vizio E470VL backlight shutting down

I am making progress but not totally fixed yet. I installed the new eprom and the TV will come on now and play SOMETIMES. Sometimes I have the screen and sometimes not. I always have the volume. What else on the video board could cause this problem. I have checked all the regulator voltages and they look good. I guess I need to see which voltage I am losing going to the main power supply board when the picture is NOT there.

[Taterbug]

Re: Vizio E470VL backlight shutting down

Just bought a used main Board off of ebay. Hope this fixes the problem..

[johnboy1313]

Re: Vizio E470VL backlight shutting down

I am making progress but not totally fixed yet. I installed the new eprom and the TV will come on now and play SOMETIMES. Sometimes I have the screen and sometimes not. I always have the volume. What else on the video board could cause this problem. I have checked all the regulator voltages and they look good. I guess I need to see which voltage I am losing going to the main power supply board when the picture is NOT there.

Just bought a used main Board off of ebay. Hope this fixes the problem..

If the problem is a cold solder joint somewhere other than the main board, be ready for the problem to persist. On the bright side though, if that is the problem, you can send the main board you just bough back.

[Taterbug]

Re: Vizio E470VL backlight shutting down

This is getting frustrating. Got board off of e-bay . Seller had a 100% rating. He said board was removed from a TV with a broken screen. Since these boards are really hard to find I took a chance and bought it. Now with this board the white Vizio light comes on and just stays on. No 12 volts on main board. I did have the 12 volts with the old main board so that shows my Inverter board which I have already replaced is ok. I went ahead and replaced the eprom on the board I just got. Still no backlight or 12 volts. I did notice that on one of the regulators (U3) that it is getting VERY HOT when I turn the set on but the voltages look ok coming out of that regulator. There is also a cap right beside it that is getting warm. I suspect the cap could be a problem even though it does not read shorted with an Ohm meter. I am going to pull the cap off of the old board and try to fix the board I just got. Any one else had any problems with regulators getting blazing hot and causing this same problem????

[ecking767]

Re: Vizio E470VL backlight shutting down

it is what it is, a bad main board. return it

[Taterbug]

Re: Vizio E470VL backlight shutting down

Problem is I dont want to pay 150 to 200 bucks for a used board. I got this one for 85 so if all possible I would like to fix it. I have not had a lot of good experiences getting boards that are said to be good off of ebay. It seems it's about a 50/50 shot. With that being said I just pulled Cap CE11 off of the board that was connected to the regulator that is overheating. Regulator is still overheating even though the voltages look normal. Still not getting enough voltage to turn the power supply on so I can get the 12 volts. I am posting a picture of the regulator that is over heating which is U3. Thinking about ordering a new regulator and gonna have to put in a new surface mounted cap. Those things are really hard to pull without destroying. Any ideas on what would cause U3 to overheat and has anyone had this problem before and also what type of cap and value is CE 11. TV is model EV470VL and main board number is 3647-0292-0150 .. 0171-2272-3253

[ecking767]

Re: Vizio E470VL backlight shutting down

U3 maybe powering the TUNER circuit, what is the output voltage? can you take a resistance measurement on the output of that regulate (tv power off) to ground.

[Taterbug]

Re: Vizio E470VL backlight shutting down

3.2 Volts output

[ecking767]

Re: Vizio E470VL backlight shutting down

did you measure the resistance from the tab of the regulator to ground, with the tv power off? you may have a short or some other components are over heating

[Taterbug]

Re: Vizio E470VL backlight shutting down

Yes I did do an ohm reading of the regulator and everything looked fine. No shorts and no other components overheating that I can see. I have a new regulator on order but what puzzles me is that the voltages read 4.8v , 2.2 v and 3.2 v at the tab...

[Taterbug]

Re: Vizio E470VL backlight shutting down

Ok finally broke down and paid 150 for a new main board that was said to have come from Vizio service center. Now the tv comes on and always has sound but sometimes backlight is on and I have picture and sometimes not. Sometimes it will play five minutes then the backlight shuts down. I have also replaced the power supply board earlier.. Any ideas what could be causing this ????

[Taterbug]

Re: Vizio E470VL backlight shutting down

Finally fixed the backlight issue. One of the backlight lamps was starting to flash and go bad. Found a replacement lamp on ebay. Installed it and this fixed the problem. Unfortunately when I was re-installing the LCD screen I chipped one of the corners destroying the LCD screen. I will just have to set this one aside until I can find another LCD screen. Does anyone know anyone who just sells the LCD screen its self and not the whole panel???

[SilentR]

Re: Vizio E470VL backlight shutting down

Taterbug, thanks for sharing your efforts to repair your tv, yours is a perfect example of why I'm skeptical of used Ebay boards. In my case, I have a Samsung that shuts off its backlight after about an hour. My first thought was a failing tube, all my voltages seem stable until the mainboard shuts down the 5V_DET pin on the power supply. Is there a reliable way to check if a tube is slowly failing?

Just did a quick check on Ebay, only thing that came up were used tubes with the typical "pulled from working TV, tested twice" comment. Does this guy's "checked" comment mean there is a procedure? I guess I could always part out my TV instead of fixing it, because technically, all my parts are from a working TV, I'll just leave out the part that it only works for an hour.

[audiofreak19]

Re: Vizio E470VL backlight shutting down

Teterbug. I did the exact same thing on my first ever tv repair. On a lnt3242h. Figured out it was the bulb that was bad. I was gonna order it and figured I would put it back together until it came in and while tightening the screws on the metal cage around the screen. The screen was off the thickness of a piece of paper and the edge cracked. Just a lesson learned when handling the screens.