Vizio VO47L FHDTV30A No signal

[ny_jets_head]

I can get to all the settings and they display fine but no matter which HDMI input I use it goes to a blue screen saying "no signal"
I switched to the rf input hoping to see snow and that also says no signal.

I know its not the source or the cable.

Any ideas.. mainboard I assume

[budm]

Re: Vizio VO47L FHDTV30A No signal

I would start by check the 3-pin Voltage regulator ICs.
Report the readings in the format as shown in this thread:
https://www.badcaps.net/forum/showth...999#post300999

[ny_jets_head]

Re: Vizio VO47L FHDTV30A No signal

Will do. Just lazy

I searched to see if someone else reported the same trouble but didn't find one.

[ny_jets_head]

Re: Vizio VO47L FHDTV30A No signal

The following are the voltages on the 1084 regulators

Device In / Out
U20 3.35-----1.82
U15 4.9------ 3.38
U19 4.92----- 2.92 ????? MAYBE THIS SHOULD BE 3.3

C5886
Q19 11.87-----11.18 Don't know if this is a Reg. cant find a data sheet for a Reg. it is marked I - O -Adj on the board


1117
U17 4.92-----3.35
U22 5.0-----3.33
U21 3.34---1.25

[budm]

Re: Vizio VO47L FHDTV30A No signal

How about the Voltage on the other pin, there are 3 pins on the device (notes: the center pin is connected internally to the big tab on top)?
Without knowing what the pin 1 Voltage is, we cannot verify what the out put Voltage will be, also without the complete P/N printing on the body we cannot tell what the voltage will be.
For example 1117-33 = 3.3V fixed regulator and pin 1 will be connected to ground, if it is adjustable regulator, then pin1 will have two resistors connected to it to determine what the output voltage will be.
So please follow the instructions. just remember that we do not have your board in front of us to look at.

These are the format of the reports we request for you to provide:
From the link:
How to identify a voltage regulator

Voltage regulators are normally found on the main or logic board. This board usually has the main CPU (or brains) of the electronic device. Voltage regulators can come in all types of different packages. See the photo below for examples (circled in red).

You can identify a voltage regulator by looking at its part number and finding its datasheet. Some common voltage regulator part numbers are 1117, 1084 and 7805.

How to test a voltage regulator

Testing a voltage regulator requires a digital multimeter. The test is simple and easy to perform. Note: Voltage regulators are typically "low" voltage. Most are 5V DC or less so there is little danger of you getting shocked, but as always, exercise caution when measuring power.

To test a voltage regulator (circled in red),

1) Set your multimeter (if manual range) to 20V DC or DCV for autoranging.

2) Put your black probe on a ground screw (circled in black). Leave it there the entire time. This is your ground.

3) Put your red probe on each of the pins including any "cut" or "stub" pin, but ignore the "fat" tab. The fat tab is "up" or "north". Number the pins left to right.

4) Report them like below along with the part number (include all lines on the IC) of the IC. Don't report "they all tested good". About once every 2 weeks, we get someone who reports that only to find out they did the arithmetic wrong or mis-interpreted the results. So report all the readings.

U100 -> pcb designation
AS1117-33 -> line 1 of the IC
0506 -> line 2 of the IC
pin 1 = 0.000
pin 2 = 3.301
pin 3 = 5.001

How to interpret the results

First you have to identify whether you have a fixed or adjustable output regulator by checking its datasheet.

Let's take an example of 2 common regulators.

Example #1 - fixed regulator

Regulator #1 - Part number 1117-33

Typing in "1117-33 datasheet" into my search engine results in (also attached)

http://pdf1.alldatasheet.com/datashe...C/1117-33.html

The datasheet tells you that the suffix, -33, denotes that 3.3V is the expected output voltage +/- 1%. So if your multimeter reading shows

AS1117-33 -> line 1 of the IC
0506 -> line 2 of the IC
pin 1 = 0.000
pin 2 = 3.301
pin 3 = 5.001

then you have a good regulator since 3.301 is within 1% of 3.3V.

Here is an example of a bad fixed regulator

AS1117-18 -> line 1 of the IC
0506 -> line 2 of the IC
pin 1 = 0.000
pin 2 = 3.301
pin 3 = 5.001

In the above bad case, the part number AS1117-18 indicates that the expected output voltage is 1.8 (suffix is -18). However, we measured 3.301 which is well over the +/- 1% tolerance.

Example #2 - adjustable regulator

Regulator #2 - Part number 1117

From the same URL and datasheet, we can see 1117 is an adjustable regulator because there is no suffix. The correct output voltage should be the voltage reading on pin 1 (adj) + 1.25V.

Here is an example of good adjustable regulator.

AS1117 -> line 1 of the IC
pin 1 = 0.000
pin 2 = 1.250
pin 3 = 5.001

So in the above example, you can see that pin 1 = 0. So 0 + 1.25 = 1.25V should be the correct output voltage for pin 2.

Here is an example of bad adjustable regulator.

AS1117 -> line 1 of the IC
pin 1 = 1.250
pin 2 = 2.250
pin 3 = 5.001

In the above bad case, you can see that pin 1 is 1.25. So 1.25 (pin 1) + 1.25 = 2.50. So the correct output voltage for pin 2 should be 2.50, but we measured 2.25 or 10% off.

(2.50 - 2.25)/2.50 = 10% off

[ny_jets_head]

Re: Vizio VO47L FHDTV30A No signal

The following are the voltages on the 1084 regulators

Device In / Out These devices don't have an ADJ voltage

LM1084 ADJ is set to ground (adjustable type)
http://www.ti.com/lit/ds/symlink/lm1084.pdf

Need to find and measure the line resistors to verify the voltages on the line resistors to verify the output voltage is correct

U20 3.35-----1.82
U15 4.9------ 3.38
U19 4.92----- 2.92

C5886
Q19 11.87-----11.18 Don't know if this is a Reg. can't find a data sheet for a Reg. it is marked I - O -Adj on the board
Adj on this one is 11.82 any ideas what this is?

A1117 (Adjustable type)
http://pdf.dzsc.com/130319/A1117%20SOT-89.pdf

Pin 3 Pin2 ADJ
U17 4.92-----3.35 ---2.09 Looks good.
U22 5.0-----3.33----2.09 Looks good.
U21 3.34---1.25-----0 connected to ground also looks good

Thanks for the info!
Revised info above.
Any ideas on Q19 what is it?

[budm]

Re: Vizio VO47L FHDTV30A No signal

"Any ideas on Q19 what is it?" Can you show me closed up picture of this Q19?

"U19 4.92----- 2.92" This one has strange output, like you said, more likely to be 3.3V, let me see the picture of this one also.

[ny_jets_head]

Re: Vizio VO47L FHDTV30A No signal

Attached are the pics of Q and U 19