Vizio D32f-E1 Powers on, has backlight, won't boot/no logo, no menu or video

[JaquesPratt]

I have a Vizio D32f-E1 LCD TV that does NOT have a TCON board.

This TV recently went through some 'death throes' and now won't boot. The first problem that began to manifest was while watching tv, the screen would 'freeze', and the image would dim over a few seconds until it was very dark. HOWEVER, the audio of the show would continue as normal. I could power off the TV for 5-20 seconds, power back on, and the video would be normal. This would occur 1-3 times when the TV was first started, and would not happen again after the TV was 'warmed up'. Not ideal, but this glitch was manageable.

After a couple of weeks of this behavior, one day I went to turn the TV on, and it wouldn't 'boot' (no logo, no menus, no video signal). The backlight would illuminate, the digital audio port would illuminate red, but the screen would stay black, except for the minor glow from the backlight.

I tried every standard method to reset, hard reset, and otherwise convince the TV to start from scratch to no avail.

I tested the 16 pin main board power plug coming from the power board, based on info I found on forums. These were the voltage readings with the power on:

Pin 1: 1.5v
Pin 2: 3.34v
Pin 3: 3.28v
Pins 4-8: 0v
Pins 9-14: 11.91v
Pins 15-16: 0v

I replaced the main board, expecting that it would fix the issue.

The voltages are now:

Pin 1: 3.34v
Pin 2: 3.34v
Pin 3: 3.28v
Pins 4-8: 0v
Pins 9-14: 11.91v
Pins 15-16: 0v

So now there's a different voltage on Pin 1, but the TV STILL will not boot.

Some might suggest replacing the TCON board, but this model of D32f-E1 doesn't have a TCON board.

Is there another voltage that is off? What else would prevent the display from showing anything, or not booting (not sure exactly what is/isn't happening). Do I need to replace the power board, or is there some other issue? Anyone have any ideas as to what has happened?

Thanks much!

[JaquesPratt]

Main Board, Power Board, and the TV's board layout.

[lotas]

Look for the problem on the board (t-con board).

[JaquesPratt]

Iotas, How does one replace this board? The connections to the LEDs are taped directly to the traces on the board, and are very delicate and finely calibrated (and there isn't much in the way to show proper alignment, either.) I also seems to me that peeling them off would likely destroy them. Any thoughts on how this is to be accomplished? Is there a specific chip that can be reflowed with a soldering hot air gun? Any other suggestions? Thanks for your input.

[lotas]

This board (T-CON) does not change, it is built into the panel on the cables, so you can look at it (smd fuse, voltage test points, resistance at the outputs of DC/DC converters...).

[JaquesPratt]

Thanks for that info. Are you able to identify the location of these components, the test points, or provide any of the specifications for the expected voltages? I have had difficulty finding any specifications for this model. I can send a detailed photo of the board if that would help. Thanks in advance!

[JaquesPratt]

Detail of the TCON board. Anything specific to check? Specific voltages? Thanks.

[lotas]

It’s hard to see, the scale is small, make the photo larger and clearer, it can be divided into parts so that you can see it...

[JaquesPratt]

I took closeups in segments, and rotated them so they read upright. So in that case, they are oriented the opposite direction from the original single photo. There is overlap between photos.

[JaquesPratt]

I have tested all the on-board transistors, and none of them appear to be bad (tested for continuity between the base and the collector, and the base and emitter).

[lotas]

Check the fuse.

[lotas]

Here, on the connector that got liquid, you can see corrosion, remove the cable and inspect the contacts.

[JaquesPratt]

The fuse checks out OK. The cable connector didn't get wet, but the clip came out when checking it and it didn't go back together easily. The cable is ok, but the clip got banged up putting it back together. I believe it's OK, too.
Anything else I should look at?

[lotas]

Check voltages at test points relative to ground.
Your chip is most likely damaged.

[nomoresonys]

That picture says it all, the chip is blown out/bad.

[JaquesPratt]

Yep, it's toast. Thanks for helping me diagnose! I really appreciate it. Time to find another TV.