Vizio E420VO - HDMI BLOWN AND BURNED - WOW

[Dgtech]

This is the first time I have ever heard of this. So I find this TV on CL for only $25. The guy tells me that Verizon was out hooking up his FIOS and SNAP... the TV is dead. Verizon ended up replacing the TV with a better one by the way. So... I get it home and open it up to find the scorched HDMI port. The shocking part to me is how bad it looked. I havent looked at they pinout or schematics for HDMI but how much voltage is going through this damn thing? I mean it cooked pretty nice. See pics.

[joshnz]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

My guess is there was some sort of fault in isolation of mains in at least 2 appliances.

[Dgtech]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

I'm gonna try to fix this board or the board that I got off of ebay - AS IS/NON WORKING board. There are some working boards on ebay for sale but they are to pricey. I hope it's just a regulator on the board that I'm getting cause I dont want to try to replace parts on the burned board. I dont trust it even if I got it going.

[tom66]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

You can probably lift off that HDMI IC and find the TV will work without it, minus HDMI of course. I would guess the protection diodes are short so it is shorting out one of the rails.

[tieny]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

Had a 37" vizio lcd tv that also had the HDMI ports burnt just like that!

[Dgtech]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

One of the first things that I checked on this burned board was the two fuses at the input and found one to be blown. I didnt spend that much time on it yet to know which one. I could try replacing some parts just for the hell of it. I have other main boards with good HDMI ports to swap out. I will check the diodes too. There is an eight pin surface mount chip that looks to be one for each HDMI, what are these usually? Seen in pic #2

[johnboy1313]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

Looks like Verizon should be happy that it didn't burn the guy's house down. Yikes! Do you think the other main board is an EEPROM issue?

[Dgtech]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

I hope it's something simple that I can swap out. I can do some surface mount stuff but not the real small crap.

[johnboy1313]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

I had the exact same set with an EEPROM issue. If I remember correctly, when plugged in the Vizio logo would light amber but there was no response from the power button. I sent the mainboard to be repaired. It cost $50 plus shipping. You can buy the pre-flashed EEPROM for $20 if you think you can do it yourself.

http://www.ebay.com/itm/Vizio-E420VO...-/140921475866

Have you tried the AS-IS main board in the set to see the symptoms?

[Dgtech]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

I still have about two days left in the ebay auction.

[SFGiants]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

Only way to smoke like that is for the Verizon source and the TV to be on alternate legs of the main AC. (split 220 to two 110V)

As stated the HDMI path is likely stressed and Vizio does little to protect these inputs.

[Agent24]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

It's goneski!

[ben7]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

Very likely a bad neutral issue in the house wiring, and they hooked FIOS up, and the fios equipment was the ground/neutral for some reason ... a lot of current went through the HDMI connector housing and burnt it up. Same thing can happen with regular coax.

[stj]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

actually connecting the cable while both units are powered could do it.

this problem has pissed me off for a very long time after almost getting thrown off a ladder while working on a sat dish.

item #1 has a switching psu and no ground reference.
so the difference between gnd and the power rail is 5v or 12v

item #2 has a switching psu and no ground reference.
so the difference between gnd and the power rail is 5v or 12v

but the difference in ground between the 2 items can be equal to rectified mains!!!

ever plugged a video cable into something and seen little sparks ??

[ben7]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

actually connecting the cable while both units are powered could do it.

this problem has pissed me off for a very long time after almost getting thrown off a ladder while working on a sat dish.

item #1 has a switching psu and no ground reference.
so the difference between gnd and the power rail is 5v or 12v

item #2 has a switching psu and no ground reference.
so the difference between gnd and the power rail is 5v or 12v

but the difference in ground between the 2 items can be equal to rectified mains!!!

ever plugged a video cable into something and seen little sparks ??

What you're talking about is due to the Y type caps.
The current that those can pass is NOT anywhere near enough to cause this kind of damage to a PCB!!!!!!!!!

[tom66]

Re: Vizio E420VO - HDMI BLOWN AND BURNED - WOW

Yes. And the shield of the connector is always connected to the TVs reference ground on the chassis and PCB. By design this should make connection first. This causes the small spark. But should be OK after that as they are now equalised with each other.

This kind of fault looks like a power surge or complete isolation failure in one device. Scary.