Vizio Symptoms and Possible Solutions

[tmwalsh]

Re: Vizio Symptoms and Possible Solutions

I have an E420VL, I think, and it has multiple voltage regulators on the board. They are a high failure part. I would suggest checking them. There is likely several posts that I made a few years ago about them. They all had a common IC that regulated to a lower voltage.
I have a feeling the 'input select' switching devices(ICs) are not doing their job as something glitched causing the HDMI, PC or TV selections to fail unless the PC has voltage on pins 9,12,13 and 15.
The boardI had(now on the workbench in the basement) failed when I plugged in a Rokku, showing 'no signal' on multiple selections of HDMI and composite. Went to use the next day, and ker-bluey nothing worked. Roku was of no help.
If you look at the maninboard, there are several ICs that I think are buffers that got taken out by the Roku, that are directly above the HDMI ports. I have not investigated further.
I would be sourcing a replacement main board unless you want to make up a DB15 PC video input plug with ~5v on several(4?) pins.
tom

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

More than 4 years ago, the guru budm said:

08-25-2014, 12:09 AM #13
budm
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Default Re: Vizio E371VL won't turn over-orange Vizio only
I have never do anything more than changing fuses and voltage regulators to fix the main board problem in Vizio. So I really do not have much suggestion.

So you are also telling me that it is likely the regulators, or the supply to them......

[budm]

Re: Vizio Symptoms and Possible Solutions

But you did test the Voltage regulators already as I suggested, right as I asked in my post 19, 24. Your symptom on this case is the strange which I also suggest you to test the Voltages around the VGA and HDMI section.
Also my post #9: I would start checking Voltages around the HDMI IC and Voltages of the Voltage regulator IC's on the main board.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

Just think about it, you are able to get the Light source (CCFL backlights (your TV)) to come on but you still do not have image on the screen, the light source is there so you can easily see the image on the screen. Light source can be CCFL, EEFL, or LED.
So at this point you can have backlights but no pictures but you can have picture if you have the TV connected to active VGA or active HDMI which points the problem to the main board but the exact cause of the problem we do not know yet.

Just to be clear, if no external input is plugged, the BL DO NOT come on, nor does the sound, or pictures as seen with flashlight.

If plug active VGA or HDMI, TV channels and sound work perfect. Then, while TV is on working correctly, I deactivate the externally plugged VGA /HDMI external connection, powered off, and then back on, the TV channel audio is heard, but the BL or picture is not there.

[budm]

Re: Vizio Symptoms and Possible Solutions

The main board is the problem, some how the BL-ON line is held lo if no external input is plugged. But as you know if you force on the BL-ON to make make the backlighst to come on, you still do not see any picture (or sound?) from the TV so it is not just the BL-ON problem, did you not already verify that, right?
So without having the Active VGA or HDMI, the controls signals are not present.

[budm]

Re: Vizio Symptoms and Possible Solutions

So: Also my post #9: I would start checking Voltages around the HDMI IC (and VGA), did you?
"Then, while TV is on working correctly, I deactivate the externally plugged VGA /HDMI external connection, powered off, and then back on, the TV channel audio is heard, but the BL or picture is not there." The no picture may be due to no switched 12V feeding the T-CON, you can easily test that.

[captainKKK]

Re: Vizio Symptoms and Possible Solutions

The EDID EEPROM IC voltages are 3.25
will start checking individual Voltage regulator IC's on the main board
I will do the "blank vga plug" test next
Currently, noting the PS pinout voltages on 13 and 14, when the BL is initiated using VGA input (then unplugging VGA while running) with everything normal inc audio, the 13 pin shows 0.2 vdc, the pin 14 = 2.75 vdc.
Powering off the tv then back on w/o the VGA results in no BL (picture) with working audio from the channel previous on. Then, pin 13=0vdc and pin 14 = 0 vdc.
The PS pinout legend is :
1-3=5vdc
4-7=SGND
8-10=12vdc
11=PSON
12=ON/OFF
13=Lamp
14=DIM

Tracing pin 14 on the MB leads to U21. I need help identifying this IC. pictured. On that IC I read 4953GM and 13203E.......
google says 4953GM Clock Synthesizer / Jitter Cleaner | Mouser..........doesn't sound like that could solve my issue......?
thanks for all the help

Finally, I found what I believe is the U21. https://cdn.badcaps-static.com/pdfs/...9d26cdeb0e.pdf

budm, pls confirm if you believe this is correct type device for my U21?