Vizio VP322 no picture no sound

[hdman97]

Hi guys
Working on a Vizio VP-322 set with no picture.
Went thru the power supply board found a couple of bad caps (dome shaped)
Tested the rest with a ESR meter ended up replacing 9 caps total.
Set has an amber light when pluged in , turns white and a relay click when power button is pressed,but no picture
After searching around found some talk of the main board being bad
F!,F2 and some regs AMC117 .The small fuses test good.
Not sure how to test the AMC1117 or if the problem is in the main board.
Any help??

[retiredcaps]

Re: Vizio VP322 no picture no sound

Not sure how to test the AMC117

Measure the DC voltage on each leg of the voltage regulator with respect to ground. If the AMC117 has a suffix like -33, the -33 will tell you it outputs 3.3V DC.

Report your voltages and if there is a suffix.

[retiredcaps]

Re: Vizio VP322 no picture no sound

Tested the rest with a ESR meter ended up replacing 9 caps total.

1) BTW, if you ended up replacing 9 caps, most here would suggest you replace them ALL especially if the remaining caps are the same brand regardless if they tested fine on the ESR or not.

2) What brand and series did you use for replacements?

PS. Pictures always help. See my sig file in post #2 on how to attach them.

[hdman97]

Re: Vizio VP322 no picture no sound

These reading were with power on. main board

using chassis grd.

None of the AMC1117 had a suffix

U7 ( 1) 2.0 (2) 3.3 (3) 4.9

U4 2.0 3.2 4.9

U8 0.0 1.2 2.5

U9 1.2 2.5 4.9

U515 1.3 2.6 4.9


could U8 with a 0.0 on pin 1 be a problem?

The caps that were replaced on the Power board were rated 105C some were
chang some were Elite.
Don't have a camera handy right now for pics
many thanks.....

[retiredcaps]

Re: Vizio VP322 no picture no sound

None of the AMC1117 had a suffix

U7 ( 1) 2.0 (2) 3.3 (3) 4.9

U4 2.0 3.2 4.9

U8 0.0 1.2 2.5

U9 1.2 2.5 4.9

U515 1.3 2.6 4.9

could U8 with a 0.0 on pin 1 be a problem?

Note you reported all the numbers to 1/10th of a decimal place. Unless your digital multimeter is very very poor, most multimeters have a 3 1/2 digit resolution so there should be another digit in your readings.

The caps that were replaced on the Power board were rated 105C some were chang some were Elite.

Let's try again.

What brand and series did you use to replace the old ones with?

[GbreadMan]

Re: Vizio VP322 no picture no sound

According to the service manual, u8 pin2 should be registering +1.2v. U4 pin2 should be +3.3v and pin3 +5.0v. Service manual doesn't mention u7, u9, or u515, nor does it mention proper output on pin1 of U8. But pin2 on u9 and u515(?) looks a bit low if it should normally be registering +3.3v.

Maybe trace back the route and see if there's an older cap on those circuits?

Dan

[hdman97]

Re: Vizio VP322 no picture no sound

Note you reported all the numbers to 1/10th of a decimal place. Unless your digital multimeter is very very poor, most multimeters have a 3 1/2 digit resolution so there should be another digit in your readings.



Let's try again.

What brand and series did you use to replace the old ones with?

I used a Fluke 79 and I only wrote down to the 1/10th.Thought that wold be close enough.
The brand on the caps was "Chang" and " Elite" printed on the cap,they were in a large kit of caps I got awhile back. Not sure what you mean by series.Sorry

[hdman97]

Re: Vizio VP322 no picture no sound

According to the service manual, u8 pin2 should be registering +1.2v. U4 pin2 should be +3.3v and pin3 +5.0v. Service manual doesn't mention u7, u9, or u515, nor does it mention proper output on pin1 of U8. But pin2 on u9 and u515(?) looks a bit low if it should normally be registering +3.3v.

Maybe trace back the route and see if there's an older cap on those circuits?

Dan

The known bad caps I had in the PS were C233 &C234.
Possible they took out U9 on the main board?
Thanks Dan

[retiredcaps]

Re: Vizio VP322 no picture no sound

I used a Fluke 79 and I only wrote down to the 1/10th.Thought that wold be close enough.
The brand on the caps was "Chang" and " Elite" printed on the cap,they were in a large kit of caps I got awhile back. Not sure what you mean by series.Sorry

Here is why resolution matters.

Voltage regulators should be within 1% of their stated value. If 3.3V is the correct value and you report 3.2V, then that voltage regulator is possibly bad.

3.3 x 0.99 = 3.267
3.3 x 1.01 = 3.333

Using generic caps like Chang and Elite is also not helping your situation.

The SMPS requires low ESR caps. Caps like Panasonic FR, FM, or FC series are "low ESR". Some caps are "general purpose". The difference in ESR between the 2 types is significant enough to prevent the SMPS from working properly.

[GbreadMan]

Re: Vizio VP322 no picture no sound

I would say it's more probable that there are more bad caps. Judging from the pics and threads available online regarding the power board on this model, all of the original electrolytic caps on this board will eventually fail (little over a dozen).

It would be recommended to replace them with the recommended brands mentioned ad nauseum by the experts on this forum (Panasonic, Rubycon, United Chemicon, Samxon except GF's, Nichicons except HM & HN series, etc.). Throw away the Changs and Elites.

[hdman97]

Re: Vizio VP322 no picture no sound

Well I have to put this on the back burner for awhile as I will be out of town.
I did go through the PS with a ESR meter and changed most that tested good anyway. Will try and order some new caps and start over.
Thanks guys!