Vizio TV e701i-a3 No pic but backlight

[Serge 125]

Hi all!! Ok I was given a Vizio e701i-a3 tv and the problem is no pic BUT it has sound and backlight. So I changed the t-con same problem so started to probe voltage on PS connector to main board and all is ok BUT one part that I'm not sure is that on the t-con fuse I get 1.xx volts, isn't it suppose to get 12v?? For now I suspect maybe the main board BUT again it could be the lcd panel. So where do I go to check the main board not much pin info on this one coampared to the PS so it's a guessing game here since no service manual (up to now in my searches). So I'm open for tips and suggestions.

THANKS in advance!!!

 

[Lightium]

Have you seen this?

 

[Serge 125]

Have you seen this?

Yep but like I said it was given to me so I don't have any sales slip, any way that offer was 9 years ago I would be very surprised that this offer is still valid today. Any way I'm just learning to fix tv's and stuff so if I can't fix it off it will go to the recycler bin BUT it would be nice if it could be fixed though....

BTW; I have changed the t-con as they say on the web page and it didn't fix the problem.

 

[Lightium]

Try taking some pics of the different sections for me.

 

[paulSH]

Yep but like I said it was given to me so I don't have any sales slip, any way that offer was 9 years ago I would be very surprised that this offer is still valid today. Any way I'm just learning to fix tv's and stuff so if I can't fix it off it will go to the recycler bin BUT it would be nice if it could be fixed though....

BTW; I have changed the t-con as they say on the web page and it didn't fix the problem.
yarovoe.org/pin-up-bonus

Check the voltage on the T-Con board. If the voltage on the T-Con board is normal, the LCD panel is probably defective.

 

[rjenkinsgb]

I did a TV repair for a friend recently, a 50" LG OLED one.

The PSU was not providing one of the needed supply rails to the screen driver board (is that the T-Con?) but tracing through the PSU circuit, the driver IC for that section was never being enabled by the main logic board.

I tried heating the PCB around the main BGA ic as much as I dared without anything dropping off it, with a hot air tool - and it worked again, for a few hours.

A "New" [ebay] logic board fixed it.

I have no idea if this is in any way relevant to the Visio, other than the mention of a low voltage on one board??

 

[Serge 125]

Try taking some pics of the different sections for me.

Here ya go!! ;-)

 

[Serge 125]

Check the voltage on the T-Con board. If the voltage on the T-Con board is normal, the LCD panel is probably defective.

Like I said in my first post at the fuse I'm just getting 1v at the t-con fuse so it's not getting the 12v (I think) that it should get from the main board. I know that from the PS I do get the 12v out to main board but from the main board at the t-con fuse I get 1v. So I suspect maybe a bad main board. Btw I tried to trace the 12v t-con wire from the PS but underneath the main board at pin 14 it says TP8 and don't see any other traces from that main board plug at pin 14. Hmm just a though here could I jump a wire from the PS 12v t-con to the t-con's fuse? It would supply the 12v to power the t-con. Like I said I'm learning here hehehe just a thought. ;-)

 

[Nigel Goodwin]

There could be a fuse on the main board that feeds 12V to the T-CON, these are usually SM and look nothing like a fuse. Or the feed to the T-CON could be switched on the main board?.

 

[rjenkinsgb]

Looking at the upper right connector or the PSU board, there are pins for PS_ON and T_CON_ON

Are both of those changing to high level when the TV is on (rather than standby)?
If they do & still no 12V out, it could be the PSU.

If one is not switching, it could be the logic board, as with the one I was working on.

 

[Serge 125]

Looking at the upper right connector or the PSU board, there are pins for PS_ON and T_CON_ON

Are both of those changing to high level when the TV is on (rather than standby)?
If they do & still no 12V out, it could be the PSU.

If one is not switching, it could be the logic board, as with the one I was working on.

Ok I've taken pics of both t-con and t-con ON and the t-con ON is 3.32v while the t-con is a normal 12v, PS-ON I get 3.3v and I get a normal 3.3v on Standby (Tv off).

So are they normal readings or something to check further on the PS side?

THANKS!!!

 

[Lightium]

Sorry for the delays. It's very hard diagnosing and trouble shooting over the internet. It be much easier if my hands and tools could reach the boards. Also modern terms for boards makes no sense to me.

 

[rjenkinsgb]

while the t-con is a normal 12v

So you are getting 12V T_con power at the PSU, but not 12V at the T-Con board itself???

 

[Serge 125]

So you are getting 12V T_con power at the PSU, but not 12V at the T-Con board itself???

That's right. At the T-con fuse I just get like 1v that's it. So for now the PS side is ok so the problem lies at the main board not passing the T-con ON and the T-con 12v. For now it looks like a cpu that would need to be re-baled OR re-flowed since it seems to have the same problem as my old LG that had the same problem.