Vizio E3D420vx No Standy Power. Why?

[DreadDelight]

Hello, I am trying to fix a tv it is a vizio model E3D420VX. When I plug it in there is no standby light. When i turn it on it comes on with the vizio symbol on the screen backlight is working. Then it turns off and the power light flashes twice and goes completely off(no standby) I opened it up and looked at the power board i don't see any burns or leaking or swelling caps. i checked the fuse with my multimeter and it has resistance not sure how much it should have. what do i look for next? If i have to, would replacing the power board fix it for sure>

[dhack61]

Re: Vizio E3D420vx No Standy Power. Why?

If your screen comes on then your fuse probably is ok.
There are several here with the same problem on Vizio e3d420's and 420's. I have the same problem with a 320. have not found a solution. You need to check the voltages coming off the power supply board with your meter. Pins 1-3 should be the standby 5.2V Voltage. Pins 8-10 should be 12v, pins 11-14... I have no idea. THose are the return voltages signals from Mainboard. I am searching for those.
For What its worth 7 out of 10 sets I have fix with no Standby light and good voltages on the power supply have been mainboard problems. But...keep checking back maybe someone will have a breakthrough.

[multimeter]

Re: Vizio E3D420vx No Standy Power. Why?

check voltage regulators on main board,vizio's are notorious for these going wrong,to check them see here https://www.badcaps.net/forum/showth...999#post300999


a very good tutorial ....scrolll to the top of the thread

[typenn84]

Re: Vizio E3D420vx No Standy Power. Why?

If your screen comes on then your fuse probably is ok.
There are several here with the same problem on Vizio e3d420's and 420's. I have the same problem with a 320. have not found a solution. You need to check the voltages coming off the power supply board with your meter. Pins 1-3 should be the standby 5.2V Voltage. Pins 8-10 should be 12v, pins 11-14... I have no idea. THose are the return voltages signals from Mainboard. I am searching for those.
For What its worth 7 out of 10 sets I have fix with no Standby light and good voltages on the power supply have been mainboard problems. But...keep checking back maybe someone will have a breakthrough.

What have you done with the ones that have been mainboard issues; do you fix the mainboard or buy/swap it out for another know working mainboard)

Ive been T/Sing mines on and off for about 6 months now. I replaced the power supply and it has been the exact same issues. I have tried looking for voltage regulators on the mainboard but honestly I cant pick out any except two (up13, up2) and those have the same voltage readings when it work and when it doesn't. They are some other 8 pin chips that might be voltage regs but I honestly dont know.

I think the issue with this thing is definitely thermal but in which component IDK. The heatsink on the main processor does get hot to the touch and reads around 112deg F with my infrared thermometer.

This has been pissing me off because its intermittent in that if i leave it unplugged for a day it will cut on after that for anywhere between 5 mins to 24 hours. I used to be able to unplug it and hold down the power button for about a min and then plug it back in to cut it on.

If anyone know hows to fix this please help or at least where do I find a schematic or something. Vizio doesnt have one, shop jimmy doesnt have one so Im real curious on how the heck to T/S this dag gone mainboard. I dont want to have to spend 50-90$ (ebay not guaranteed to work) or 120$ shop jimmy for a new one on a tv that cost 440$ new now.

[martino]

Re: Vizio E3D420vx No Standy Power. Why?

http://www.youtube.com/watch?v=cNFzBJELFoU

you need to watch this,voltage regulator U33 often bad and another one but cant remember now the number...

[typenn84]

Re: Vizio E3D420vx No Standy Power. Why?

http://www.youtube.com/watch?v=cNFzBJELFoU

you need to watch this,voltage regulator U33 often bad and another one but cant remember now the number...

Thanks but Ive already seen this one. I have a different board and there is no U33 on mines. Ive check all the voltage regulators and they seem to be correct.

I am currently looking at the power supply again. I have 2 and they may both be bad. I thought I had bad diodes so I ordered new ones. For the top 2 ,they were measuring around 150 on the diode test, so I assumed they were bad (saw diodes should be between 300-800); this measurement was on both boards. Anywho ordered new ones (8) from digikey and they measured the same thing out of circuit and in circuit. Dont know about you but I doubt that I have 12 bad diodes.
The other 2 diodes on the board that I thought were bad were zenerdiodes. When I do a diode test on them when solder in the board they beeb (measure 0); take them out and it reads 550 or so. So then I got curious and measure the holes on the board without the zener diodes in place and it beeped also, so I dont know if thats normal or not. It doesnt help that I can find no schematics for this blasted board.

Im going in circles so I may start my own thread here soon.

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

Hello;

I have a vizio E3D420VX and it doesn't work, but it has a different issue. I was watching a movie one day, and I heard a loud noise like something exploded. The TV turned off and it won't come back on. I took the cover off the TV but I don't see anything burnt or anything that would look bad to someone with little to no experience. I have pictures of the boards that I can upload. Please help....

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

Here are the pictures of the boards

[budm]

Re: Vizio E3D420vx No Standy Power. Why?

Can you take new pictures with better lights, it is kind of dark? also take the pictures of the bottom side of the power supply/inverter combo board.
What kind of tools do you have?

[Agent24]

Re: Vizio E3D420vx No Standy Power. Why?

I see a blue high voltage ceramic capacitor on the PSU that looks like the top has blown off.

It is nearby to what looks like the main switching transistor\IC. I also see an electrolytic capacitor nearby that might be bulged.

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

I have 4 more pictures of the board.

I have a volt meter and basic understanding of electronics, but I definitely need someone to hold my hand.

Which capacitor is the one that has the cap blown off? All capacitors seem flat, that's why I wasn't sure what is wrong. Normally it is clear to see a bulging capacitor...

Thanks for help in advance....

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

Here are the pictures of the back side

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

I think I found what you were talking about, it's C103 and it has a small hole on the top. I will replace it and see what happens. Thanks so far.

[Agent24]

Re: Vizio E3D420vx No Standy Power. Why?

What else does C103 connect to? Does it connect to the device on that heatsink nearby? It's possible more than just C103 has blown.

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

yes it does connect to that

[Agent24]

Re: Vizio E3D420vx No Standy Power. Why?

What is the device on the heatsink? Can you read the part number?

[budm]

Re: Vizio E3D420vx No Standy Power. Why?

That is the Snubber cap connected in parallel with the Source and Drain pin of that SMPS IC on the heat sink.

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

Here is a closeup of it, do you think that might be bad as well? How would I check that?

It is DB30AT 00465R

[Denkodt]

Re: Vizio E3D420vx No Standy Power. Why?

It might be D830AT 00465R, the 8 looks like a B

[Agent24]

Re: Vizio E3D420vx No Standy Power. Why?

If the snubber capacitor blew the IC might be dead too.

It seems to be an FSQ0465, see attached datasheet. You need to check at least the IC for shorts in the internal FET and check the other snubber components too. Probably a diode and some resistors.

Check the datasheet Page 18 for the example circuit. Yours should be similar.