Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

[johnboy1313]

I just picked this thing up. Probably paid too much for it but I felt sorry for the guy who is apparently being evicted from his house (who knows). Anyhow, There's an obvious burnt spot and a bulging cap, on the PSU, but no blown fuses. There's also bulging caps on both inverter boards. Chances are there's a bad regulator or two on the main board as well.

The traces on the back of the panel look OK, do you think it's worth repairing this PSU, or should I just try to find a used one?

[tom66]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Bad caps will cause those inductors to run hot but they are probably OK. Replace the caps. Normally Chemicons do not fail. Poor design if it can kill those!

[johnboy1313]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I Replaced 1 35V 470uf cap on the PSU, 2 35V 680uf caps on each inverter, and a 10A fuse on the master inverter. The results speak for themselves.

[tom66]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I see only one problem, the logo below the screen says "Vizio", it should say "Piece of overpriced crap"
Nice easy fix.

[johnboy1313]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I see only one problem, the logo below the screen says "Vizio", it should say "Piece of overpriced crap"

Nice

[tom66]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Some people do not know that they are just another re-badging company. Not designed in US, not made in US.

[xredhawk]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

hi , i got same burn spot on psu i moved coil and leg lifted off the board , i dont know what to solder that leg to as the green print on board burnt off, also has same bad cap, any help would be great!

[johnboy1313]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Pictures??

[ben7]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

hi , i got same burn spot on psu i moved coil and leg lifted off the board , i dont know what to solder that leg to as the green print on board burnt off, also has same bad cap, any help would be great!

Get a thick piece of solid wire and connect the parts again, the way they were before the trace got ripped up.

[Bktimby]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I Got the same problem but the board is burnt so bad the board started to peel up as you can see in the picture. I'm going to change the one capacitor. But before I start I was wondering if I'm wasting my time with the board that bad burnt.

[budm]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

That is the symptom of bad filter cap in the Pi filter, the inductors are trying to block the High frequency AC ripple from flowing through (inductor blocks AC and passes DC, cap passes AC, blocks DC. You need to change the caps as a set since bad cap can look normal.
To fix that solder solder joints, you need to add more regular solder (not lead free) to the connections and remove the solder, clean the leads real well and use solder flux to solder the parts back on.

[Bktimby]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I finally got home long enough time to start working on the board. When I was cleaning the board the rest of the strip came off. Is there a way to repair it or trash it? Please see the pic.

[tom66]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

It's repairable but you're going to need to figure out where each end of that inductor went so you can solder wires to each end.

[Bktimby]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Please bare with me trying to fix a board for the first time. I would like to hook it up to see if it works but would like an opinion on it first. If you need to see other pictures you can scroll up in this thread. Thanks

[PL519]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Hi,
looks good so far, since both inductors are in parallel. Looking at your picture it seems you have changed C241, but not the other filter caps. I would recommend to change C240A und C240B too as they are responsible for the high ripple current through the inductor coils!
Greetings,
Wolf

[Bktimby]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Will do thanks PL519

[Dflammer]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I have the same problem, same model. I will be replacing the 5 popped caps. I have voltage to the inverters but, nothing going out of the pink wires that plug into what I believe are the backlights. Both inverters have same dead end. I re-soldered the coils, got the 24v to the inverters. Will post results after the parts arrive.

[Dflammer]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

I changed out the 4 popped caps on the inverters and the 1 bad cap next to the burnt coil on the power board. Still no backlight. I had good 24 volts into the inverters before the cap repair and still have 24v to the inverters now. I got nothing coming out of the inverters. I have attached a pic of the Master inverter board. After I ordered the replacement caps, I noticed a little scorching on the IC that is between the caps and have attached a picture. How can I tell if the backlights are still good? I don't want to waste 40$ on a replacement inverter only to find that the backlights are dead.

Thanks for the help, it is appreciated!
Dave

[budm]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Do you have BL-ON (INV-ON) command signal from the main board to turn on the backlights Inverter?
Please read the basic troubleshooting guide.
BTW, that IC is blown and more likely the fuse and the Power MOSFETs on the inverter board.
You cannot tell if the lamps are good or not unless you take the panel apart to inspect them, but that is not 100% for sure by using visual inspection.

[Dflammer]

Re: Vizio VO47LFHDTV10A burnt spot on PSU, replace or try to fix?

Thanks Bud. I have the 24 volts and the 'on' voltage is 3.5v at the inverter connector from the power board. There is the same voltage at both ends of the fuse and no resistance. Due to the scorched IC on the master inverter, I ordered 2 used inverters(same inverter model nos.) from ebay and will give that a shot. Replacing the TV is going to cost me about 7-800, so 30$ is OK for determination. The power board was scorched at the coils and I replaced the cap that had popped next to it. I replaced the 4 caps on the 2 inverters, all 4 were popped. I seem to be getting the voltages everywhere from the power board, sound and LCD are good and displaying/playing, just no backlight & no power coming out of either inverter.. I appreciate your help in this forum, GOD bless.