Vizio e371vl dead after suspected lightning

[amlederer]

I picked up a vizio e371vl (also a e422vl) off of craigslist for free. Owner suspected they had died from a lightning strike. That is all I know of their history. Working on the 371 first. Plugged in it is completely dead, no standby light, vizio logo does not light up any color. Back pulled off. I am a novice when it comes to TV's. Most of my experience deals with PC's and PC monitors. Visual inspection does not show anything obvious, caps look good, no burn marks. I checked the volts at the plug on the power board. The 5volts all look good when plugged in, the 12v and the on/off all stay at zero, even when power button is pushed. I assume and this could be totally wrong that I am looking at something on the main board? Pics fo boards and my meter below. Will this meter be sufficient or do I need to invest in something better?

[budm]

Re: Vizio e371vl dead after suspected lightning

If you do have 5VSTBY to run the main board but the main board does not send any command signals to turn on the rest of the power supply, the the main board will be the first place to check. You are going to need good digital meter to test the Voltages, especially the LDO regulator ICs.

[CapLeaker]

Re: Vizio e371vl dead after suspected lightning

Test the main board first. Sounds like it doesn't return PSON signal to the PSU. After that you can force the PSU on to see if it is o.k. Yeah, I do think too that you do need a better meter than that.

[amlederer]

Re: Vizio e371vl dead after suspected lightning

Any recommendations on a decent meter that won't break the bank (amazon prime or local big box would be nice). I do think that one of the fuses on the main (right of the two right below the plug from power board) on the main board is blown.

[amlederer]

Re: Vizio e371vl dead after suspected lightning

Would this be a decent low cost choice? http://www.amazon.com/Etekcity-Digit...tal+multimeter

[fzabkar]

Re: Vizio e371vl dead after suspected lightning

Here is a better photo of the main board, p/n 3637-0652-0150(6C):
http://cdn2.bigcommerce.com/n-d57o0b....1280.1280.jpg

The LG 42LV4400 TV uses the same MediaTek MT5376 SoC. The service manual has circuit diagrams (with pinouts) and a partial datasheet.

Service manual for LGE 42LV4400 TV:


The MT5376 SoC requires the following voltages:

VCC3_STDBY -- 3.3V
VCC3IO -- 3.3V
VCCK -- 1.1V
VCC2IO -- 1.8V DDR2 supply
AVDD33 -- 3.3V analog supply
AVDD12 -- 1.25V analog supply

JVC's JLC37BC3000 TV uses the same main board (017122713276), but I couldn't find a service manual for it. :-(

[ozzy214]

Re: Vizio e371vl dead after suspected lightning

I personaly use the sears dvom, craftsmen., Think it was 20 bucks. Use for electronics and car work.

[amlederer]

Re: Vizio e371vl dead after suspected lightning

I will pick up a new meter at lunch today. where would be a good spot to start looking on the mainboard?

[fzabkar]

Re: Vizio e371vl dead after suspected lightning

Your photos are useless for troubleshooting purposes, and I don't feel right about using other photos without permission. In any case I can't read the IC references on any of the photos.

That said, the LDO regulators that were mentioned by budm (I think I can see 4 of them) look like this:

http://inter-chip.pl/images/product/20694_03a275.jpg

Measure the voltages on all three pins plus tab.

There are also several switchmode regulators. Assuming these are all step-down regulators, then the output voltages should be present at the coils. I can see two 4R7 coils and three 220 coils, so this would suggest that there are at least 5 switchmode regulators.

There are 4 coils near the front panel pushbuttons, but these are associated with a class-D audio power amp.

[amlederer]

Re: Vizio e371vl dead after suspected lightning

Should these be measured with the set plugged in or not plugged in?

[CapLeaker]

Re: Vizio e371vl dead after suspected lightning

regulators you measure with the set on, your meter set at DC Volt, your black lead on chassis GND and probe the pins and the tab of these regulators with the red probe.

[amlederer]

Re: Vizio e371vl dead after suspected lightning

Will check them tonight (although it will have to be plugged in and off as the set does not turn on)

[fzabkar]

Re: Vizio e371vl dead after suspected lightning

Should these be measured with the set plugged in or not plugged in?

Where do you think that voltage comes from?

[amlederer]

Re: Vizio e371vl dead after suspected lightning

Very True. LOL
So I did some testing with my new meter. F1 is shorted. All of the LDO regulators are 0V at all posts. But worse is U46 appears to have fried.

[budm]

Re: Vizio e371vl dead after suspected lightning

The surge came through the HDMI ports, I bet the cable/Sat box was probably damaged too.
You will need a new main board.
The two fuses on the main board, one is for 5VSTBY, another one is for switched 12V.

[amlederer]

Re: Vizio e371vl dead after suspected lightning

F2 shows 0V on both sides, F1 shows 5V on one side and 0V on the other

[amlederer]

Re: Vizio e371vl dead after suspected lightning

The surge came through the HDMI ports, I bet the cable/Sat box was probably damaged too.
You will need a new main board.

Thanks Budm, I have a line on a board with a bad eeprom. Do you think the eeprom from this board is still good or cooked as well?

Time to dig into the e422vl I have as well

[amlederer]

Re: Vizio e371vl dead after suspected lightning

Looks like the same thing happened on the 422 except no fuses were blown. Just a chip out of the similar chip next to the had I ports, I do also have voltage at the on off on the power board but everything acts dead