Vizio VO320E Bad Power Supply Board?

[alja]

Hi, I have a Vizio VO320E that I'm trying to fix. It turns on, the logo comes white and when off the logo is amber. I've been reading all the posts in the forum about the issue and did the readings hoping that anyone could help me to find out what's wrong.

I started for the fuses in the main board

Off

F1 > 5.18
F2 > 0.00

On

F1 > 5.38 - 5.35
F2 > 1.87


Before I read the Regulators I went to the power supply board and Check the fuse and read


Off

F1 > 0.00

On

F1 > 0.00

From what I have read the fuse is bad but I don't know really how to interpret this info.

Then I went to the regulators:

ADJ = Pin 1
Out = Pin 2
In = Pin3

Power OFF Vizio Label Amber

TU52
EH13A
928K80
1117
p1: 0.00
p2: 0.00
p3: 0.00

U2
9gb
1117
p1: 0.00
p2: 0.00
p3: 0.46

u8
9gb
1117
p1: 0.00
p2: 0.00
p3: 0.00

U9
9gb
1117
p1: 0.00
p2: 0.00
p3: 0.47

U7
9gb
1117
p1: 0.00
p2: 0.00
p3: 0.47

U4
9gb
1117
p1: 2.19
p2: 3.49
p3: 5.51

U5
9gb
1117
p1: 0.00
p2: 0.00
p3: 0.46

U11
7805CT
pin 1 out: 0
pin2 ground: 0
pin 3 in: 0

Power ON Vizio Label White

TU52
EH13A
928K80
1117
p1: 0.00
p2: 0.44
p3: 0.01

U2
9gb
1117
p1: 2.19
p2: 3.54
p3: 5.49

u8
9gb
1117
p1: 0.00
p2: 1.36
p3: 3.61

U9
9gb
1117
p1: 1.39
p2: 2.72
p3: 5.59

U7
9gb
1117
p1: 2.27
p2: 3.66
p3: 5.59

U4
9gb
1117
p1: 2.27
p2: 3.66
p3: 5.60

U5
9gb
1117
p1: 1.46
p2: 2.84
p3: 5.45

U11
7805CT
pin 1 out: 0
pin2 ground: 0
pin 3 in: 1.93

thanks.

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

When you specify a voltage measurement, are you measuring ACROSS the fuse (red one end / black the other) or from one end of the fuse to ground? If the second one, you need to measure the voltage on both ends of the fuse to see if it is bad.

[alja]

Re: Vizio VO320E Bad Power Supply Board?

Thanks Tom, I did the measurements both ways

when I measure each fuse using both ends (red in one end and black in the other end) I only get 0.00 in all the fuses with the TV ON and OFF.

When I measure ground to each side of the fuse I get

TV ON VIZIO label white

F1 (on the power supply board) > Fluctuates from -0.15 to 0.15

F1 (on the mother board) > 5.84 on both ends of the fuse

F2 (on the mother board) > 2.03 on both ends of the fuse

TV OFF Vizio label amber

F1 (on the power supply board) > Fluctuates from -0.17 to 0.17

F1 (on the mother board) > 5.91 on both ends of the fuse

F2 (on the mother board) > 0.00 on both ends of the fuse

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

Those indicate good fuses.
On the 12V output of the power supply, what voltage do you see?

[alja]

Re: Vizio VO320E Bad Power Supply Board?

Reads 0.00

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

Is that with the logo white or orange? Please try it with the logo white.

[alja]

Re: Vizio VO320E Bad Power Supply Board?

I don't really know how to achieve that...., I did measure unplugging the cable from the power board to the mother board and use the 12V pins to get the reading, but in order to turn the tv on (vizio lable white) I'll have to plug the cable back in which wont leave me room to measure.

[alja]

Re: Vizio VO320E Bad Power Supply Board?

Ok, I managed to measure and I got 2.02 with the VIZIO label white and 0.00 with the VIZIO label amber.

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

OK, this indicates either a problem with the power supply, or the load attached to it -- more likely power supply than not.

Do you have any resistors (through hole type) available in the range of 100 to 470 ohms? The main board and other circuits can be disconnected from the power supply, and the power supply can be tested separately. A car brake light can be used as a load on the 12V rail to test that more reliably.

[alja]

Re: Vizio VO320E Bad Power Supply Board?

You mean like using a 12v auto bulb to test the 12v out of the power supply? if so what would be the resistors for?

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

The resistors would be used to trigger the PS ON (Power Supply ON) signal which tells the PSU to turn on, the auto bulb used to provide a load on the 12V. For now 12V can be tested without bulb as load, if it is bad without load there is no point in testing it with a load.

[alja]

Re: Vizio VO320E Bad Power Supply Board?

ok, could you point me out how to do that?

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

On the connectors on the power supply board, do you see a pin marked PS_ON, STBY or REMOTE?

[alja]

Re: Vizio VO320E Bad Power Supply Board?

yes PS_ON

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

OK, locate (any) pin which is 5V in standby mode.

You need to unplug the connector from the main board, and run the resistor between the 5V and the PS_ON. (Leave this connector disconnected from the main board, leave it connected to the power supply.)

Then plug the power supply into AC. Check the 12V, is it good or bad? Significantly higher, or barely changed?

One other thing, because we have had the odd weird measurement before on this forum, can you make a check of, for example a charged car battery, to see if your meter can display 12V? (Nominally 13V for a car battery, if the car is to start properly. There's a small chance the "1" digit has stopped working... unlikely but we would be chasing a wild goose if your meter reads incorrectly.)

[alja]

Re: Vizio VO320E Bad Power Supply Board?

Ok, I'm getting the resistor from R Adio Sh ack. Any particular resistance? or just any between 100 and 470 ohms

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

Get a few 100 ohm and a few 470 ohm to cover the full range of usable values. Use 470 ohm to start.

[alja]

Re: Vizio VO320E Bad Power Supply Board?

alright, I have put one 470 ohms resistor between the ps_on and 5v pins and the reading on the 12v pins is still the same 2.02. I guess ...... the power board is bad?

[tom66]

Re: Vizio VO320E Bad Power Supply Board?

See above:-

One other thing, because we have had the odd weird measurement before on this forum, can you make a check of, for example a charged car battery, to see if your meter can display 12V? (Nominally 13V for a car battery, if the car is to start properly. There's a small chance the "1" digit has stopped working... unlikely but we would be chasing a wild goose if your meter reads incorrectly.)

[alja]

Re: Vizio VO320E Bad Power Supply Board?

Sorry I forgot to comment.... I did test my multimeter with the car running and gave me little over 13v