Vizio VW42LFHDTV10...Brother Mikes TV...

[PlainBill]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

I was able to:

- Turn on the TV
- Vizio Logo turn from orange to White
- Screen is Black (not even backlite or a flash, completely black from off to on)
- Not able to turn OFF TV unless unplug

From what I've read from this thread and other thread it, the problem is from the main board mostly U33. I used my multimeter to check and got the following number

Chip Location / Vin / Vout / Adj,Gnd

U2 / 5.19 / 3.30 / 2.0
U4 / 5.19 / 3.30 / 2.0
U7 / 3.30 / 1.28 / 0.0
U8 / 5.19 / 3.30 / 2.0
U9 / 3.30 / 1.52 / 0.0
U33 / 5.19 / 3.30 / 2.0

What is the part number on U9?

PlainBill

[taydu]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

It's K1117S15

Thank you

[PlainBill]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

It's K1117S15

Thank you

OK, that output voltage is correct.

PlainBill

[taydu]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

any other suggestion Bill ?

[Dgtech]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

two caps on both inverter are bulge, will get it replace but it shouldn't effect the main board ( cannot turn off after it turned on?)

I thought the same thing, but it did. Get that fixed first, then see what you got after. Did you also check the driver chips on the inverter? See pic for usual failure.

[taydu]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

to update, I replace the cap and when power up i can see the back lite come on but nothing appear, still unable to turn off the TV.

[Dgtech]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Thats interesting that you had the bad caps on the inverter board first and now this. I wonder if it's not logical that one problem created the other? Maybe there were simply two separate problems. Either case, Visio seems to be the worse sets out there for failure rate, even worse than Samsungs.

[ecundiffaz1]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

I thought the same thing, but it did. Get that fixed first, then see what you got after. Did you also check the driver chips on the inverter? See pic for usual failure.

hi newbie here,

not sure if this will post right. i have the common problem with my inverter chip that is shown in your picture. what causes that to go bad?

[PlainBill]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

hi newbie here,

not sure if this will post right. i have the common problem with my inverter chip that is shown in your picture. what causes that to go bad?

Poor design of the inverter causing the FETs to short, most likely. There is a mod to prevent it.

PlainBill

[ecundiffaz1]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

is there anyone i can send this board to for repair and do the mod?

[Spetznazer]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Hi all, my first post here. I found Badcaps.net pretty informative and helpful with my other repair of VIZIO crap.
So I've got another fixer-uper. Symptoms are similar: when I press ON button set turns on (with click), LED changes color to white, blue screen appears with NO SIGNAL sign(obviously inverters are good), 2 sec after screen turns black and LED to ambient and after 4-5 sec set turns off (I hear click). I am able to turn it in by pressing ON button again. I took some measurements when set was able to be on(turned it on several hundreds times). It seems like PS is Ok, all caps looks good no bulging or burned spots on board. Huge cap's readings are 160V when not turned on and around 400V when on. PS feeds 5.2V, 11.8V and 24.4V to main board and inverters respectively. Readings of ADOs are as follow:
(I used this method of measuring - black goes to GROUND at screw hole, red goes to the pin in 3-2-1 order)

ADO# Pin 3 Pin 2 Pin 1 Type Model
U4 5.05 3.27 0 adj 17-33L 6E1L
U5 3.27 1.94 0 adj AMC1117 F0615J
U6 5.07 3.29 0 ADJ 17-33L 6E1L
U7 3.28 1.82 0 FIX 17-18L 6E5L
U8 5.01 3.28 0 ADJ 17-33L 6E1L
U9 3.27 1.81 0 FIX 17-18L 6E5L
U10 3.28 1.81 0 FIX 17-18L 6E5L
U16 5.02 2.25 0 ADJ 17-25L 6D1L
DU2 5.01 3.29 0 ADJ 17-33L 6E1L
DU3 5.01 2.49 0 ADJ 17-25L 6D1L
DU4 3.31 1.24 0 ADJ AMC1117 F0615J

I am not too deep with electronics but learning fast. Did I have to measure voltage between pin 2 and 3 also?

[PlainBill]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Hi all, my first post here. I found Badcaps.net pretty informative and helpful with my other repair of VIZIO crap.
So I've got another fixer-uper. Symptoms are similar: when I press ON button set turns on (with click), LED changes color to white, blue screen appears with NO SIGNAL sign(obviously inverters are good), 2 sec after screen turns black and LED to ambient and after 4-5 sec set turns off (I hear click). I am able to turn it in by pressing ON button again. I took some measurements when set was able to be on(turned it on several hundreds times). It seems like PS is Ok, all caps looks good no bulging or burned spots on board. Huge cap's readings are 160V when not turned on and around 400V when on. PS feeds 5.2V, 11.8V and 24.4V to main board and inverters respectively. Readings of ADOs are as follow:
(I used this method of measuring - black goes to GROUND at screw hole, red goes to the pin in 3-2-1 order)

ADO# Pin 3 Pin 2 Pin 1 Type Model
U4 5.05 3.27 0 adj 17-33L 6E1L
U5 3.27 1.94 0 adj AMC1117 F0615J
U6 5.07 3.29 0 ADJ 17-33L 6E1L
U7 3.28 1.82 0 FIX 17-18L 6E5L
U8 5.01 3.28 0 ADJ 17-33L 6E1L
U9 3.27 1.81 0 FIX 17-18L 6E5L
U10 3.28 1.81 0 FIX 17-18L 6E5L
U16 5.02 2.25 0 ADJ 17-25L 6D1L
DU2 5.01 3.29 0 ADJ 17-33L 6E1L
DU3 5.01 2.49 0 ADJ 17-25L 6D1L
DU4 3.31 1.24 0 ADJ AMC1117 F0615J

I am not too deep with electronics but learning fast. Did I have to measure voltage between pin 2 and 3 also?

No, but there are a number of problems with your chart. First, for milleniums humand have counted 1-2-3 etc. Some of us have the habit ingrained. When checking the voltage of an LDO regulator the first pin is the Gnd / Adj pin, the second the output, the third the input. The second problem is you have misidentified a number of the regulators. Some of the numbers do not make sense; I'm not sure if you took a short cut, or there is a problem with your meter.

Rather than change the chart to a more conventional layout, here are some problems.


ADO# Pin 3 Pin 2 Pin 1 Type Model
U4 5.05 3.27 0 Fix 17-33L 6E1L (1)
U5 3.27 1.94 0 adj AMC1117 F0615J (2)
U6 5.07 3.29 0 Fix 17-33L 6E1L (1)
U7 3.28 1.82 0 FIX 17-18L 6E5L
U8 5.01 3.28 0 Fix 17-33L 6E1L (1)
U9 3.27 1.81 0 FIX 17-18L 6E5L
U10 3.28 1.81 0 FIX 17-18L 6E5L
U16 5.02 2.25 0 Fix 17-25L 6D1L
DU2 5.01 3.29 0 Fix 17-33L 6E1L (1)
DU3 5.01 2.49 0 Fix 17-25L 6D1L
DU4 3.31 1.24 0 ADJ AMC1117 F0615J

You have misidentified a number of fixed regulators as adjustable.

Those with a 1 in parenthesis (1) indicates either a problem with the ground point you selected, your meter, or a regulator out of tolerance. These regulators have an accuracy of 1%. All are low by more than that. This is within the power input tolerances of most ICs, but is curious.

U5 (marked with a (2)) has another problem. Either you did not measure the voltage on pin 1, or it is defective. You are correct, it is an adjustable regulator. The output (pin 2) of an adjustable LDO regulator will ALWAYS be 1.25 volts above the reference (pin 1). 1.25 is a standard voltage used in (I believe) memory ICs. 1.92 is not a standard voltage.

PlainBill

[Spetznazer]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Thank you Bill for a quick reply. Sorry I was wrong with which ADO is adjustable and which is not. All ADOs I assumed are adjustable have pin1 ON A BOARD marked as "adj" that's where my misinterpretation came from. Thanks for correcting me. So I took two independent tests again with two different testers. And yes I failed to check voltage on a pin1 of U5. Results are:

ADO____PIN1______PIN2______PIN3
U4.........0.............3.26..........5.04.......17-33L
U5.........0.69.........1.93..........3.26.......AMC1117
U6.........0.............3.28..........5.04.......17-33L
U7.........0.............1.81..........3.26.......17-18L
U8.........0.............3.26..........5.01.......17-33L
U9.........0.............1.80..........3.26.......17-18L
U10.......0.............1.80..........3.26.......17-18L
U16.......0.............2.48..........5.01.......17-25L
DU2.......0.............3.27..........4.99.......17-33L
DU3.......0.............2.48..........4.99........17-25L
DU4.......0.............1.23..........3.29.......AMC1117

As I understand U5 and DU4 are O'k since the drop between pin1 and pin2 is about 1.25V on both. Well it makes it more difficult. All caps on mainboard look good without any sign of failure, but I am afraid that it is not a proof of that they are good. Also there is a lot of other chips on board that may fail. Any ideas on a data I already have?

P.S. Hey Bill is that Diamond Head on a background of your avatar?

P.S.S. I forgot to mention the TV set is VIZIO GV42L.

[PlainBill]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Thank you Bill for a quick reply. Sorry I was wrong with which ADO is adjustable and which is not. All ADOs I assumed are adjustable have pin1 ON A BOARD marked as "adj" that's where my misinterpretation came from. Thanks for correcting me. So I took two independent tests again with two different testers. And yes I failed to check voltage on a pin1 of U5. Results are:

ADO____PIN1______PIN2______PIN3
U4.........0.............3.26..........5.04.......17-33L
U5.........0.69.........1.93..........3.26.......AMC1117
U6.........0.............3.28..........5.04.......17-33L
U7.........0.............1.81..........3.26.......17-18L
U8.........0.............3.26..........5.01.......17-33L
U9.........0.............1.80..........3.26.......17-18L
U10.......0.............1.80..........3.26.......17-18L
U16.......0.............2.48..........5.01.......17-25L
DU2.......0.............3.27..........4.99.......17-33L
DU3.......0.............2.48..........4.99........17-25L
DU4.......0.............1.23..........3.29.......AMC1117

As I understand U5 and DU4 are O'k since the drop between pin1 and pin2 is about 1.25V on both. Well it makes it more difficult. All caps on mainboard look good without any sign of failure, but I am afraid that it is not a proof of that they are good. Also there is a lot of other chips on board that may fail. Any ideas on a data I already have?

P.S. Hey Bill is that Diamond Head on a background of your avatar?

P.S.S. I forgot to mention the TV set is VIZIO GV42L.

If the voltage regulators are good, here is very little that can be done to repair these board without schematics and the proper test setup. At this point I would say your only option is to replace the main board.

Yes. And of course, the beach is Waikiki Beach.

PlainBill

[Spetznazer]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Thank you Bill for the effort to help. I decide to heat up the board with heat gun to see if it will lead me somewhere but with no luck. Set acts the same way. i downloaded service manual that says it is for the same model. Not much of info there for me but I found troubleshoot diagram for DC-DC converter so I went through checking Volts again. In a manual it says that the voltage on a pin2 of U5 must be about +1.8V (which is 1.94) also it says that pin2 of U8 also must be about +1.8v where it is about 3.3V. Either manual is wrong or board was revised and changed after manual was written. I went trough the diagram and checked all pins it was mentioned and got right data except that pin1(PWON) of J7 connector from board to PS was 4.6V and not up to 3V as in manual but that can be O'k right?.

[PlainBill]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Thank you Bill for the effort to help. I decide to heat up the board with heat gun to see if it will lead me somewhere but with no luck. Set acts the same way. i downloaded service manual that says it is for the same model. Not much of info there for me but I found troubleshoot diagram for DC-DC converter so I went through checking Volts again. In a manual it says that the voltage on a pin2 of U5 must be about +1.8V (which is 1.94) also it says that pin2 of U8 also must be about +1.8v where it is about 3.3V. Either manual is wrong or board was revised and changed after manual was written. I went trough the diagram and checked all pins it was mentioned and got right data except that pin1(PWON) of J7 connector from board to PS was 4.6V and not up to 3V as in manual but that can be O'k right?.

Yes. Every design I've seen the 'power on' pin drives the base (or gate) of a transistor. The threshold is normally about 2 volts to turn on the supply. A higher voltage would not cause problems.

The information about U5, pin 2 is significant. There are three reasons that output voltage would be higher. One - a change in design - doesn't make sense. Another is that the regulator is defective. A third is that the IC that is receiving the 1.8 volts is defective. Actually, the whole design doesn't make much sense. Why use an adjustable regulator when a fixed one is available?

PlainBill

[Spetznazer]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

All right. It seems like U5 have to go. I'm gonna replace and see what gonna happen. To be continued...

[GbreadMan]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

I was a Vizio TV parts swap person for a couple years; mostly performed simple board swaps but the repair vendor gave us the service manuals for all the Vizio TV's at the time.

According to the VW42L_HDTV10A manual from 061107T (6th of Nov 2007?), U8 pin-1 on the dc-dc converter should be +5v, and pin2 should be +3.3V (doesn't say anything about pin3).

However, the manual's flowchart says U5 pin2 should be around +1.2V while power switch is on (p.91)...two other chart discrepancies follow:

U6 pin2 = +1.8v (doesn't specify whether power switch should be turned on or off)
U10 pin2 = +2.6v (with power switch on)

The manual / flowcharts do not mention several components at all, including U9,U16,DU#, etc. Perhaps there's a manual somewhere for that specific PCB? Is it manufactured by LG?

I would upload the manual but I'm not sure where.

Hope this helps,
Dan

[retiredcaps]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

I would upload the manual but I'm not sure where.

If the pdf file is less than 9.5MB, you can use the manage attachments button below the text entry area to upload the file so it is hosted here at badcaps.net.

[GbreadMan]

Re: Vizio VW42LFHDTV10...Brother Mikes TV...

Finally found the PSS at the bottom of one of the posts saying it's a GV42L. Scratch everything I said.