VIZIO VX37L No Picture or Sound Suspect voltage regulator

[neverexisted]

Hi guys got a VX37L that lights up when button is pressed with a white light but no picture or sound.

I think as stated in other threads I have bad regulators

here are the readouts of the regulators:
U2- 2.02
3.26
5.15

U3- 11.91
0.00
5.01

U4- 5.06
3.03
2.04

U7- 0.00
1.0
3.29

U8- 2.02
3.5
5.01

U9- 0.00
1.51
3.40
U10- 1.36
0.00
5.01

U33- 2
3.29
5.02


now i understand this is a common issue and I am just going to order all of the part number AMC1117 and replace all as they are cheap and I have a full workstation so with some tweezers and hot air it should be pretty quick.

But I am hoping for some clarification understanding this for next time.

So if its an adjustable regulator does that mean this is done automatically when I connect them to the board? Would it be better to get "static" regulators to replace them? And I'm assuming based on the tutorial I read posted by another user that pin one should equal the adjustment to pin 2?

I'm a little slow today so forgive if that sounds a little stupid.

Thanks guys.

[budm]

Re: VIZIO VX37L No Picture or Sound Suspect voltage regulator

U2: adj reg, good, 1.25 Vref +2.02 adj = 3.27 Vout.
U2- 2.02 (adj?)
3.26 (out?)
5.15

U3, 5V fixed reg., good
u3- 11.91
0.00
5.01

U4 looks bad. 1.25 Vref + 2.04 adj = 3.29V
u4- 5.06
3.03 (out?) bad
2.04 (adj?)

U7 looks bad, need P/N and pictures to verify if it ia adj or fixed type.
u7- 0.00
1.0
3.29

U8 OK.
u8- 2.02
3.5
5.01

U9 needs P/N and verification.
u9- 0.00
1.51
3.40

U10 needs P/N and verification.
u10- 1.36 (OUT?)
0.00 (adj? or GND?)
5.01

U33 OK
u33- 2
3.29
5.02

Your measurement is not consistent regarding to the readout of the pins.

[neverexisted]

Re: VIZIO VX37L No Picture or Sound Suspect voltage regulator

I was a little shaky today TBQH last time I worked on a live tv I shorted AC to to DC ground and sparks flew been a little nervous around them ever since.

I've been electrocuted a few times in the past its a bit of a phobia for me but im trying to get over it. I mainly do computers and game system reworking and repairs but I'm trying to expand my knowledge beyond swapping bulged caps etc.

Low voltage doesn't scare me but live AC absolutely does.


I'll go through and retest everything tomorrow and get you some close ups and PN verification. Thanks for your response your help and time is appreciated.

[neverexisted]

Re: VIZIO VX37L No Picture or Sound Suspect voltage regulator

Also I will reread your posts which were very thorough by the way and see if I can understand a bit better before I ask too many questions.

But..... Am I to assume an adjustable regulator is generally: pin one + pin 2 = pin 3 (voltage out) in all cases? So this means that the out put on pin three is determined by the input on pin 1? Or is that all just completely wrong?

[budm]

Re: VIZIO VX37L No Picture or Sound Suspect voltage regulator

"But..... Am I to assume an adjustable regulator is generally: pin one + pin 2 = pin 3 (voltage out) in all cases? "
For Adjustable regulator; It is the Vout (pin 2) = Adjust pin (pin1) + 1.25Vref
Pin 3 is an Input pin.