vizio l42hdtv10a

[fixerupper75]

Picked up this set today. It will power on. No picture or sound. And it will not turn off. I think mainboard. I have all voltage 24v,12v 5vsb 5vps-on 3vbl but no dimming. Pictures will come later.

[fixerupper75]

Re: vizio l42hdtv10a

My camera is on the fritz. But here are some voltage reg. reading.

u4
In 5
out 3
adj 0

u5
I 3.3
o 1.9
.69

u6
i 5
o 3.2
a 0

u7
i 0
O 0
a 0

u8
i 5
o 0
a 0

u9
i 0
o 0
a 0

u10
I 0
O 0
A 0

U16
I 5
O 2.48
A 0

U18
I 0
O 0
A 0

DU2 I 5.5 O 3.3 A 0 DU3 I 5 O 2.48 A 0 DU4 I3.25 O1.25 A 0

[jeffecor]

Re: vizio l42hdtv10a

replace u9 on the board and recheck the voltage on all of them. Normally just that voltage reg goes out from what I seen.

[budm]

Re: vizio l42hdtv10a

u8
i 5
o 0
a 0

Input is 5V and no output? it is dead if that is the case or shorted load (you can check the resistance on output pin against GND).

[fixerupper75]

Re: vizio l42hdtv10a

Will do that tomorrow. I found u18 shorted. Replaced it and still the same.

[budm]

Re: vizio l42hdtv10a

Will do that tomorrow. I found u18 shorted. Replaced it and still the same.

Shorted at the Input pin or output pin? It may be shorted out MLCC.

[fixerupper75]

Re: vizio l42hdtv10a

I replaced u8, u9, and u18. Still same results.What is the MLCC?

[budm]

Re: vizio l42hdtv10a

So when you removed the regulators, did you check the resistance between the solder pads where the regulators were against GND to see of the shorts went away?
MLCC: Multi Layer Ceramic Capacitor.

[fixerupper75]

Re: vizio l42hdtv10a

yes i did check and the short didn't go away.

[budm]

Re: vizio l42hdtv10a

yes i did check and the short didn't go away.

So it is not the Regulator IC. So was it the input in or the output pin that shows shorted circuit?
I would remove the MLCC on the pin that shows shorts circuit.

[fixerupper75]

Re: vizio l42hdtv10a

Sorry but i haven't been able to troubleshoot this down to the component. I have ordered a new mainboard and will follow up later.

Thanks for the help!!!!!

[fixerupper75]

Re: vizio l42hdtv10a

Ok replace the main board. Still the same. There is no bl_on voltage or no dim light voltage. I got 4.4dvc on the ps-on. What you guys think?

[budm]

Re: vizio l42hdtv10a

Where did you get this board from? Those signals are generated by the main board.

[fixerupper75]

Re: vizio l42hdtv10a

Electroparts off of ebay. I think I've made a rookie mistake the board number doesn't match. Orginal 3642-0062-0150 new 3420-0012-0150. ugh.

[fixerupper75]

Re: vizio l42hdtv10a

Is their any other site besides ebay or shop jimmy to get parts?

[vinceroger69]

Re: vizio l42hdtv10a

a quick google search no one seems to have the board in stock maybe for now whilst your looking put your old board back in and maybe we can do some more fault finding like budm suggests in post 8, also most repair kits online consists of these so double check on your board
Kit contents
Replacement components for U5 , (U4, U6, U8).

[fixerupper75]

Re: vizio l42hdtv10a

My soldering skill could use the practice.