Vizio VX32L turns on with backlight, no video or sound

[Andrew M]

Re: Vizio VX32L turns on with backlight, no video or sound

OK, so I'm rereading posts, have new adjustable regulators on order (to replace the wrong AP1117E18 fixed voltage regulators I put in ). Not much to do until I get those parts replaced, but attached are a series of photos of the main board.

To summarize:
Problem: Vizio VX32L (2007) TV powers on, backlight is on, but no sound, no picture, and only way to turn TV off is unplug. All other controls are unresponsive (both remote and the buttons).

Inspected/Tested/Tried:
No visible caps blown, no other smoked components seen/smelled.
reseated cables/ribbons
tested fuses on main board OK (0 ohms), 5V on one, 12V on the other
Tested outputs from power supply- 5V, 12V, and 24V all present in appropriate places.
Tested fuse on T-con board(?) (at top under a bunch of metal), 0 ohms.

IC Top Mid Bottom
U7 3.3, 1.8, 0 (after I replaced with the wrong regulator!)
U9 is 3.3, 2.2, 0.4 (after I replaced with the wrong regulator!)
U8 is 5.1, 3.3, 2.0
U33 5.0 3.35 2.1
U2 5.1 3.3 2.0
U4 5.1 3.3 2.1
U15 5.15 in , 5.05 out

Status:
Waiting until correct regulators come. Is there anything else I should be testing while I'm waiting? Is it likely I cooked something else putting in the wrong regulators, in which case I should look for a new main board?

[Andrew M]

Re: Vizio VX32L turns on with backlight, no video or sound

I soldered in the new (correct adjustable AP1117EGDICT-ND regulators) into u7 and u9. The problem of no sound/no picture, but + backlight still exists. These are the readings after i replaced u7 and u9 (done the correct way-pins 1-3)
These were all AMC1117,F0646J

IC PIN 1 Pin 2 pin 3
u7 0.001; 1.258; 3.351
u9 0.249; 1.493; 3.350
u33 2.095; 3.359; 5.08
u8 2.080; 3.339; 5.12
u2 2.071; 3.332; 5.13
u4 2.079; 3.334; 5.12

according to what I have read, pin 2=(pin 1+1.25), which puts these about where they should be.

On second inspection, I did notice there is some corrosion under c34 and c18 (220uF, 25V caps near u7 and u9)- see attached photo of cap (cathode has corrosion on both) . Worth replacing?

Other thoughts?

[budm]

Re: Vizio VX32L turns on with backlight, no video or sound

Yes, replace the cap, it looks like the right leg is coming off.

[Andrew M]

Re: Vizio VX32L turns on with backlight, no video or sound

I replaced c18 and c34. I am still getting the same symptoms. Where to from here?

[Mr Bill]

Re: Vizio VX32L turns on with backlight, no video or sound

I don't know where else to troubleshoot but if you get to the point of replacing the main board shoot me a PM. I have the same board i pulled from a broken screen VX32L.

[Worminizer]

Re: Vizio VX32L turns on with backlight, no video or sound

Yes I got a reading of no resistance all around the base of the fuse holders of F1 And F2. I am still hoisting the white flag my good man. My first attempt at board repair certainly wont be trying to revive this poor Frankenstien!

I live in Orlando, FL, USA. Only a couple of hours from woodyfl. I pm'd him and offered to buy his set so that I can continue posting progress in the forum. Its just killing me knowing that the set is sitting there so close, and I got no closure. I read these posts and follow them like I'm watching a movie. I love the conclusion, the answer, the fix. I NEED to know!

[kevinm34232]

Re: Vizio VX32L turns on with backlight, no video or sound

I am too very curious what is going on with these Vizio main boards. I picked one up the other day that had orange LED but would not do anything else. The voltages were all there and the regulators were good. I ordered a new main board and Im going to compare readings to see if I can find out anything. I am thinking that it's a VPU failure and that's why there are so many unfixed main boards but that's just a guess..

[Worminizer]

Re: Vizio VX32L turns on with backlight, no video or sound

There are some of them actually have corrupted eeproms. Why they get that way, I don't know, but vizio, with enough coaxing, will send out a reset box and usb thumb drive to reset them. I had one with 2 seconds to black that flashed the vizio logo for a couple seconds, then turned off. The reset box rewrote the eeprom through the vga and usb ports. I have no idea how.

[kevinm34232]

Re: Vizio VX32L turns on with backlight, no video or sound

Lack of information and/or lack of complete service manuals does not help either.. I'd like to know more about eeprom info or if the eprom chip can be replaced...

[rsaritzky]

Re: Vizio VX32L turns on with backlight, no video or sound

I've seen some references on how to confirm one of these regulators is in fact bad. I found a video on Youtube (referred to in this thread I think) but the video was fuzzy.

If the output is supposed to be 3.3v and is low, this guy connected a 3.3v power source (2 AA batteries). He then powered up the TV and it worked.

But I wanted to make sure I'm connecting the test power source correctly:

a. + side of battery output to the output terminal of the regulator
b. - side of battery to a common grounding source, e.g. a screw holding the mainboard

Is this correct?

Ron

[budm]

Re: Vizio VX32L turns on with backlight, no video or sound

See here first.
https://www.badcaps.net/forum/showth...391#post274391

[ntznaz]

Re: Vizio VX32L turns on with backlight, no video or sound

You guys rock. What a wonderful resource. Just got my 32" repaired after testing/replacing u33 on the main board. Now I just need to find a place for this tv. Already bought a 48" E series to replace it.