Vizio XVT3D650SV - Help

[bammbammfran]

Re: Vizio XVT3D650SV - Help

As I mentioned, your voltage regulators should have a ground pin so you should not get voltage on all 3 pins and of course they should not be almost the same voltage.
You can confirm the ground with an ohm meter.

on the voltage regulators
If you look at them with the largest tab to the left
On the 1117 adjustable smaller one top pin would be input, center pin and large tab would be output and the lower pin would be ground
On the larger one, the top pin would be output, the center pin and large tab would be Ground and the lower pin would be input

While you are retesting the 2 voltage regulators.
I would remove the wire from the pin 13 out of the 16 pin plug at the power board side and check that wire separately for voltage and then check the actual pin of the power supply too
To remove the wire, lift slightly on the white tab of the plug at that pin with something pointy and then slide the wire out

also check pin 1 on one of the larger connectors for voltage at dim-pwm-signal

[newpey]

Re: Vizio XVT3D650SV - Help

OK, my board looks a little different from your picture. Please see picture

R310A: -5.17 on both sides

A: -5.23
B: -5.23
C: 0
D: 0

[newpey]

Re: Vizio XVT3D650SV - Help

OK, I started testing away. THEN I noticed the ground pin is burned through on one of the voltage regulators on the main board when I was testing ohms

I checked the fuses around it and they all seem to be working fine.

Writing on it is: 7805CG RKA07. Do I just order one and replace it? IS there an actual part number? Could anything else be messed up from this guy?

Also, I am really unsure how to test the voltage regulators correctly. If I use the ground wire from the 16 pin plug OR if I use the metal on the TV, my dcv appear to be about the same on all pins and tab. I would like to understand how to correctly test these.

I am excited to see an actual issue!

[newpey]

Re: Vizio XVT3D650SV - Help

I just read https://www.badcaps.net/forum/showthread.php?t=22231 Great thread! Now I understand how to test them.

How do I find the part number / replacement for the voltage regulator in question? I can't find that info anywhere

[bammbammfran]

Re: Vizio XVT3D650SV - Help

OK, I started testing away. THEN I noticed the ground pin is burned through on one of the voltage regulators on the main board when I was testing ohms

I am excited to see an actual issue!

Do Not get too excited yet ! That center pin is not supposed to reach the board like the other 2 pins do
So if you think that is what is wrong ?? Sorry !!

[newpey]

Re: Vizio XVT3D650SV - Help

Do Not get too excited yet ! That center pin is not supposed to reach the board like the other 2 pins do
So if you think that is what is wrong ?? Sorry !!

Well then back at it!

Tested the wires and pins from main board and on power board:
1 0
2 0
3 0
4 0
5 -5.18
6 -5.18
7 -5.18
8 -5.18
9 -5.18
10 -5.18
11 -5.18
12 -5.18
13 -5.14
14 -5.13
15 0
16 -5.13

5 volt fuse -5.13 on both sides
12 volt fuse 0.02 on one side and 0 on the other

On the 2 voltage regulators, regardless of how I ground the black probe, I see the same or very similar volts across the pins minus ground.

[budm]

Re: Vizio XVT3D650SV - Help

The regulator 7805 5V regulator is not going to show any input (12V) voltage because you do not have the 12V output from the power supply since the 12V/24V power supply is not working right now.
You should download that datasheet and look at the pinout of the 1117.

[budm]

Re: Vizio XVT3D650SV - Help

OK, my board looks a little different from your picture. Please see picture

R310A: -5.17 on both sides

A: -5.23
B: -5.23
C: 0
D: 0

What do you use for the black probe? Is the reading showing minus 5.23V (-5.23) reading?

"R310A: -5.17 on both sides" that will indicate open Base-Emitter junction of that transistor, unless I am wrong, the Emitter is connected to Ground from what I can see on the traces of the board.

[newpey]

Re: Vizio XVT3D650SV - Help

What do you use for the black probe? Is the reading showing minus 5.23V (-5.23) reading?

"R310A: -5.17 on both sides" that will indicate open Base-Emitter junction of that transistor, unless I am wrong, the Emitter is connected to Ground from what I can see on the traces of the board.

Yes it shows minus.. I have the meter set to 20DCV I dont understand what that means as it is not possible to have negative volts?

I either put the black probe on pin 1 for ground or use the chassis.

[newpey]

Re: Vizio XVT3D650SV - Help

The regulator 7805 5V regulator is not going to show any input (12V) voltage because you do not have the 12V output from the power supply since the 12V/24V power supply is not working right now.
You should download that datasheet and look at the pinout of the 1117.

Gotcha. That makes sense

[bammbammfran]

Re: Vizio XVT3D650SV - Help

Well then back at it!

Tested the wires and pins from main board and on power board:
1 0
2 0
3 0
4 0
5 -5.18
6 -5.18
7 -5.18
8 -5.18
9 -5.18
10 -5.18
11 -5.18
12 -5.18
13 -5.14
14 -5.13
15 0
16 -5.13

5 volt fuse -5.13 on both sides
12 volt fuse 0.02 on one side and 0 on the other

On the 2 voltage regulators, regardless of how I ground the black probe, I see the same or very similar volts across the pins minus ground.

Well, I don't know how to say it but, this looks all wrong
1through4 should be +5
5-9 should be grounds
10-12 should be 12 but may show zero
and on the voltage regulators are you still saying that all the pins are showing 5 volts ??

are the batteries in your tester good ?
Maybe you have the red and black lead plugged into the tester backwards ?

what do the pins at the power supply show with the main board wire disconnected ?

[newpey]

Re: Vizio XVT3D650SV - Help

The probe wires are soldered on to the meter. Battery is fine as well. If I am reading the pins correctly then they go like this..

back side
16, 14, 12, 10, 8, 6, 4, 2

front of plug that is facing me
15, 13, 11, 9, 7, 5, 3, 1

[budm]

Re: Vizio XVT3D650SV - Help

Can you show us the meter?

[bammbammfran]

Re: Vizio XVT3D650SV - Help

The probe wires are soldered on to the meter. Battery is fine as well. If I am reading the pins correctly then they go like this..

back side
16, 14, 12, 10, 8, 6, 4, 2

front of plug that is facing me
15, 13, 11, 9, 7, 5, 3, 1

JUST TO MAKE SURE
See the picture
ALSO, please check these with the plug from the main board unplugged
USE GREEN marked pins for black probe of the tester

[budm]

Re: Vizio XVT3D650SV - Help

I think we are are doing wild goose chase with all these wrong readings. The only correct reading is the one on the main filter cap that shows around 160VDC.

[newpey]

Re: Vizio XVT3D650SV - Help

I think we are are doing wild goose chase with all these wrong readings. The only correct reading is the one on the main filter cap that shows around 160VDC.

I am going to get a new tester this morning. Maybe it is the issue. I will post all new readings one I get it.

[newpey]

Re: Vizio XVT3D650SV - Help

OK the multimeter I had was defiantly NOT matching the new one. Now maybe we can actually get somewhere! Sorry about that guys!!

Here are the readings:

Power board plug
1 5.1-5.3
2 5.1-5.3
3 5.1-5.3
4 5.1-5.3
5 0
6 0
7 0
8 0
9 0
10 0
11 0
12 0
13 0
14 0
15 0
16 0

caps on power board:
C951A 5.22
C951B 5.22
C951C 5.22

C800A 77.7
C800B 77.7
C800C 77.7

-----

Main board

Fuses
F3 5.1
F1 0

Voltage Regulators
U8
in 0
out 0
gnd 0
tab 0

U38
in 0
out 0
gnd 0
tab 0

[bammbammfran]

Re: Vizio XVT3D650SV - Help

ok
That is better
Now you can recheck pin 13 that budm wanted to see the value of when powered on and off and connected to the main board
also check it at the power supply with wires to cn202 disconnected

[newpey]

Re: Vizio XVT3D650SV - Help

No change on pin 13 when pushing the power button with cn202 connected or disconnected

[newpey]

Re: Vizio XVT3D650SV - Help

The TV *normally* goes through a boot up stage when you first plug it in. During that time the vizio logo lights up orange then proceeds to flash orange and white. Once it is complete the logo go back to orange and the power button becomes enabled and you can turn on the TV.

I am guessing the power button will not change the voltage as the tv is not "booted up".
I am not sure I just know that it used to take 1-2 minutes before the power button worked