Vizio VW42L HDTV10A no picture or sound

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

Ok i was mistaken about the 1st pin. it says o/f. no voltage reading. i attached some pictures. I have got to say i have been searching for a fourm like this for a long time, lots of useful info.

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

Ok i was mistaken about the 1st pin. it says o/f. no voltage reading. i attached some pictures. I have got to say i have been searching for a fourm like this for a long time, lots of useful info.

Well, I have some suggestions and information for you.

First, try to make your posts appear as if you were writing an English composition. The 'stream of consciousness' posts get old very quickly and are ignored. Punctuation and capitalization are not arbitrary, the make the result more readable.

Next, the pictures COULD have been better, but that are good enough to give me some ideas.

You indicated the TV responds when turned on. Does it also respond when you turn it off?

On the picture of the power supply output connector, three pins catch my attention. Pins 1 and 2 appear to be control signals to the inverter. Pin 10 appears to turn the main supply on. Please verify this by measuring the voltages on the 12V, 24V, and 5V pins and these three pins with the TV off and after it has been turned on.

The picture of the main board is good for an initial quick look, but is too dark to review in detail. I have been unable to identify any LDO regulators. Would you take another with better lighting (no flash, please).

PlainBill

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

The t.v. vizio light comes on as soon as you plug it in (dim white). When pressing the power button it does get brighter, and slowly dims. After pressing the power button again it does go back to the dim light again.

It does seem (from the vizio light) that the t.v. is working normal. but no backlight and no sound.



Ok so i remeasured all readings from the power suppy. I will start from top to bottom.
T.V. off
.543
.4
0
0
0
0
0
0
0
5
5
5

Now with t.v powered on.
100 mv
3.65
11.47
11.47
0
0
0
23.3
23.3
5
5
5


Thanks again for any help.

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

Those numbers are a little strange, but they may have decided to use one signal line to control both the main supply and the inverter.

The picture is a big improvement. I've marked it up and identified a few important points.

Yellow circle - Probably a 1084 type LDO regulator

Orange circle - Almost certainly a 1117 family LDO regulator.

Black circle - a mounting screw to be used as ghe frond point.

Measure the voltage on the three pins of these regulators, using the screw circled in black as a ground point. Report the readings.

Blue circle. Look for any components in this area that have a component identifier that starts with F (for fuse). Check any you find.

PlainBill

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

Ok i took the readings of those two regulators.

The first one the yellow circle measured (from left to right)

5.11 3.28 0

the part # is L071 903T63

The second regulator orange circle(left to right) only has two pins

11.45 9.04

part # 17809, This also has other markings at the pin outs. 92 on the left, and 46 on the right.

I checked all the fuses and they all seem to be good in that blue circle as well

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

Ok i took the readings of those two regulators.

The first one the yellow circle measured (from left to right)

5.11 3.28 0

the part # is L071 903T63

The second regulator orange circle(left to right) only has two pins

11.45 9.04

part # 17809, This also has other markings at the pin outs. 92 on the left, and 46 on the right.

I checked all the fuses and they all seem to be good in that blue circle as well

I think one of us got orange and yellow mixed up. Yellow circle has two obvious pins, the tab is the third, and by the part number is a 9 volt regulator, so that appears to be good. Orange circle has three pins and the part number isn't recognizable, but I would expect to see 3.3 volts out, so that is also good.

There are more switching regulators on the board. It is going to be very difficult to determine if they are working properly. Perhaps it is time to check price and availability on a replacement board.

PlainBill

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

After i was done testing the the regulators, i turn the power off via switch. I noticed a very faint ringing noise in the area of the power board. I dont know if this i normal or not.

I however can not detect witch component it is comming from though. sounds like the upper right corner near the transformer

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

After i was done testing the the regulators, i turn the power off via switch. I noticed a very faint ringing noise in the area of the power board. I dont know if this i normal or not.

I however can not detect witch component it is comming from though. sounds like the upper right corner near the transformer

Probably not a problem. The power supply has two sections, one is always on when the power cord is plugged in. People with good hearing may be able to hear the standby SMPS, I can't.

PlainBill

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

Ok so i should replace the main board?

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

Ok so i should replace the main board?

I vote yes.

PlainBill

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

Ok i will remeasure voltage after i install a new board.

thanks for the help

[JIMSKIN]

Re: Vizio VW42L HDTV10A no picture or sound

Ok i installed a new main board and it works great now.

I took voltage readings again. the only change is the o/f pin.

5.35 o/f
3.65
11.47
11.47
0
0
0
23.3
23.3
5
5
5

After removing the board i noticed some other fuses that i did not check on the back side. i plan on checking those as well

Thanks for your help.

[XmouseX]

Re: Vizio VW42L HDTV10A no picture or sound

Thanks

[oljoe28]

Re: Vizio VW42L HDTV10A no picture or sound

Guys, how do I identify the tcon or U33 on my vizio board? the model number on my board appears as dps-283ap. The problem that I am facing is black vertical lines on the left side facing the LCD.
If anyone can provide some direction on this, that will be great. thank you

[Dgtech]

Re: Vizio VW42L HDTV10A no picture or sound

Look in ebay for the tcon for your model number TV.

[chris30506]

Re: Vizio VW42L HDTV10A no picture or sound

I have the same issue: No pic, no sound, backlight is orange until power button is pressed, then turns white. I confirmed all voltages stamped on the power supply are good. I have installed 2 separate main boards from vizparts (correct boards based on TV Serial Number) but still have the same issue. Their tech support now say's issue is most likely caused by bad inverters or T-Con board. I'd rather replace boards than solder components. I have the service manual but it's a little over my head. Is there a simple way to rule out one or the other?
Thanks!!!

[budm]

Re: Vizio VW42L HDTV10A no picture or sound

If you look at the screen in the front or look at the back of the screen in the dark room, do see any glow on the screen? We need to find out if the backlights are working or not first.
Any pictures of YOUR boards?

[Dgtech]

Re: Vizio VW42L HDTV10A no picture or sound

1. Check the caps on inverters. 2 each.

2. Check the driver chip visually for pin 26 burning off - common failure.

3. Measure the resistance between the two soldered leads of each of the four fets on both master and slave boards and post the results here. You should find that they should all measure the same ~ 8.5k ohms I think. If there is one reading lower, that means the driver chip (32 pin surface mount) needs changed.

[chris30506]

Re: Vizio VW42L HDTV10A no picture or sound

Thank you very very much for the fast responses. I am working out of town and will return home on Friday and will check the items you have referenced. As far as I can tell, there is no back light but I will check further in a darker room. I apologize for the poor quality of the photos (I mainly took them to catch board part #s before leaving home). On photo 328 of one of the inverter boards, It appears that the chip may have a burned spot at the red arrow. Depending on where pin 1 is, this could be pin 26, correct? It could also just be an artifact in the horrible photo. I removed the tape covering the caps on both inverters and there are no visible bulges. Again, THANK YOU!!!! What a wonderful experience to have a forum with nice, professional, helpful people!

[budm]

Re: Vizio VW42L HDTV10A no picture or sound

That is a very common failure of these inverter board, the IC blew up and also may have taken out the MOSFETs with it.
The board will also need the mod.
http://s807.photobucket.com/user/bud...01266054068297