Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Here are the reading from the pins on the main board from PS.

Pin names from PS to Mainboard

1)PS ON
2)12V
3)12V
4)12V
5) not used
6)SGND
7)SGND
8)SGND
9)5VSB
10)5VSB
11)A
12)B
13)C

PS OFF
1) 0.015
2) 0
3) 0
4) 0
5) Not used
6) 0
7) 0
8) 0
9) 5.178
10) 5.178
12) 5.178
12) 0
13) 0.009

PS ON
1) 3.118
2) 11.86
3) 11.86
4) 11.86
5) Not used
6) 0
7) 0
8) 0
9) 5.178
10) 5.178
12) 5.178
12) 0
13) 0.009

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Check the voltages on the two ceramic fuses on the main board.(both sides of fuses with respect to chasis ground)
Upper right center now that you can "turn the TV on"

If you have voltages, take a look at U33, known bad LDO voltage regulator.

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

check the voltages on the two ceramic fuses on the main board.(both sides of fuses with respect to chasis ground)
upper right center now that you can "turn the tv on"

if you have voltages, take a look at u33, known bad ldo voltage regulator.

ps on

f1 = 11.85
f2 = 5.166

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

measure U33 voltages with power on, DC volts with respect to chasis ground.(mainboard)

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Output is 3.28, Input 5.13, Adjust 2.03, Ground pin is at 3.29.....? 3.29 on ground? What type of regulator is this? Anyone have spec sheet?

[dick_barton]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Probably an adjustable voltage regulator so there's no ground pin, it's an adjust pin which is also connected to the tab.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

pin 1 = ground or voltage of adjustment(resistor voltage divider, depending if it's a fixed or adjustable regulator)
pin 2 = output (tied to large tab, same pin)
pin 3 = input

Orientate the chip with tab up, pin 1,2,3 left to right.

For adjustable voltage regulator, Pin 1 + 1.25volts = output voltage.
It would seem your U33 is correct.

I assume the chip is a 1117?

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

pin 1 = ground or voltage of adjustment(resistor voltage divider, depending if it's a fixed or adjustable regulator)
pin 2 = output (tied to large tab, same pin)
pin 3 = input

Orientate the chip with tab up, pin 1,2,3 left to right.

For adjustable voltage regulator, Pin 1 + 1.25volts = output voltage.
It would seem your U33 is correct.

I assume the chip is a 1117?

Oooo. Gotcha!

1) 2.03
2) 3.28
3) 5.13

Yes, it is a 1117

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Ok, with the TV "ON", check all the other voltage regulators on the main board.
Some will be fixed regulators (look for a number like 12 or 33 or 15 in the number on the chip, indicates output voltage of the regulator,ie 1.2v, 3.3v) others adjustable regulators just like U33.

Does you Vizio logo light on the front of the TV remain steady bright white, or starts out bright and then dims?

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Starts out bright and then dims.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Ok, that should do that.
Now go back and shine a light on the screen to see if a very dim image appears.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

The logo light remains dim? It should stay dim while the TV is on.

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Ok, that should do that.
Now go back and shine a light on the screen to see if a very dim image appears.

Nope. No dim image. There is no voltage going to the Inverters. The logo light starts bright and then stays dim afterwards.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

All the wires are connected to their original positions?

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

All the wires are connected to their original positions?

Yes. Also, I'm unable to turn off the TV by the power button. I have to unplug it in order for it to turn off.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

OK, that indicates a main board problem. Check all the voltage regulators for proper output. If they are OK, I can only suggest a main board replacement. (ie. out of ideas)

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

The voltages on the regulators U2, U9, U8, U7, Q27, U3, U33. All are within tolerance. I just don't understand why there isn't voltage going to the inverters.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

Where are you measuring voltages to the inverters?

[Naturallyk2]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

From the PS on the 24V rails.

[cliff_hootarski]

Re: Vizio VO47L-FHDTV10A turns on and then off (3 seconds)

OK, so no 24v.