Vizio VW42L HDTV10A no picture or sound

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

The service manual MIGHT be wrong, you might be making a mistake (yes, it happens), or there might be a bad component.

The usual design has a series of regulators. The main power supply puts out 5 V nominal (it often is .1 or .2 volts higher). The first LDO regulator drops it to 3.3 volts for the processors. The 3.3 Volts also is the supply for the 2.5 volt regulator, which in turn supplies the 1.8 volt regulator. When I see a regulator whose input voltage is too high I look for the regulator that is supplying too high a voltage.

PlainBill

The best i can tell the U4 power only comes from the pinout from the powersupply and only goes through 1 capacitor. Shouldn't U4 be showing an output too? or will the higher voltage not allow any output

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

The best i can tell the U4 power only comes from the pinout from the powersupply and only goes through 1 capacitor. Shouldn't U4 be showing an output too? or will the higher voltage not allow any output

Without seeing the schematic, I can't be sure, but in general I would say U4 is defective.

???? When I looked at the pucture you provided, I saw U4 was missing; I assumed you had removed it. Looking at the other pictures in the thread, U4 is missing in them, too.

PlainBill

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

Without seeing the schematic, I can't be sure, but in general I would say U4 is defective.

???? When I looked at the pucture you provided, I saw U4 was missing; I assumed you had removed it. Looking at the other pictures in the thread, U4 is missing in them, too.

PlainBill

yeah i know it's weird, very weird. I thought maybe it was on the bottom so i pulled it and looked and it wasn't there. It's just 3 blobs of solder but no chip. I had to rob another cap for a rca 32" power supply to get it going since i'm stumped on this one. When i get some more caps in i'll pop it in and proceed with some of the other regulators and try troubleshooting some more. Maybe the 5.1 volts is correct on U4

[questor42]

Re: Vizio VW42L HDTV10A no picture or sound

From what I have seen the VW42L HDTV10A and VX42L HDTV10A
mother boards do not have a U4 and it's not in the parts list either.

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

Hey Bill, Do you think the Tcon board could have anything to do with my problem?

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

Hey Bill, Do you think the Tcon board could have anything to do with my problem?

Possible, but unlikely. I'd try disconnecting the tcon and seeing if you can now get sound. IF that happens, by all means replace the tcon. If the TV shuts down, or if you still have the same symptoms, that is probably not the cause.

PlainBill

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

Possible, but unlikely. I'd try disconnecting the tcon and seeing if you can now get sound. IF that happens, by all means replace the tcon. If the TV shuts down, or if you still have the same symptoms, that is probably not the cause.

PlainBill

Good advice I'll try that. I got another cap to go back in my main but haven't had time to get it in. I'll do that and try pulling the tcon cable. Thanks Bill

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

Good advice I'll try that. I got another cap to go back in my main but haven't had time to get it in. I'll do that and try pulling the tcon cable. Thanks Bill

OK Bill, I tried unplugging the tcon and it just backlit the lcd with no colors but that's typical i think with a bad tcon. I also checked fuse on tcon and it was good. From the manual I have checked everything and all seems good except for that weird U4. The Manual says it should have 3.3 volts out but it has none but it has the 5 volts in. I don't understand how the manual can show an out voltage without a regulator even being there. After that the U33 voltage out was supposed to be 3.3 volts and it's only reading about 2.3. All other components tested well.

[Dgtech]

Re: Vizio VW42L HDTV10A no picture or sound

When in doubt, change it out. I wouldn't suspect a part for a week and not have it on the way in the mail. These parts are cheap. If you can spare a dollar or two, take a risk. You've come this far.

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

When in doubt, change it out. I wouldn't suspect a part for a week and not have it on the way in the mail. These parts are cheap. If you can spare a dollar or two, take a risk. You've come this far.

Board or component?
Boards are very hard to find for this model.

[saturnknts]

Re: Vizio VW42L HDTV10A no picture or sound

Board or component?
Boards are very hard to find for this model.

component. i'm working on one and its about 20 bucks shipped from mouser unless you need chipquik like i did which makes it almost 30 bucks shipped.

you might also consider ordering caps for both inverters as 3 of four of mine were bulging. i can give you part numbers if you like. and ill let you know if all my parts work later tonight if the usps hurries up

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

component. i'm working on one and its about 20 bucks shipped from mouser unless you need chipquik like i did which makes it almost 30 bucks shipped.

you might also consider ordering caps for both inverters as 3 of four of mine were bulging. i can give you part numbers if you like. and ill let you know if all my parts work later tonight if the usps hurries up

I'm at a loss of what components to try on the main board. No bulging caps at all. I really don't think it's the inverter since the keyboard controls don't work. Only way to power down is to unplug.

[saturnknts]

Re: Vizio VW42L HDTV10A no picture or sound

I'm at a loss of what components to try on the main board. No bulging caps at all. I really don't think it's the inverter since the keyboard controls don't work. Only way to power down is to unplug.

okay, rmoody. First off ignore U4 and ce9 and ce10. all three DO NOT have anything on or in them. leave them alone.

as stated yesterday i used the following parts and probably over killed the replacement of caps, but since i dont have an ESR meter yet i felt better safe than sorry. and yes i always order one extra of everything in case i screw up. although since there are 17 of the 220uf caps it was cheaper to order 25

here is what i ordered from mouser and im sitting here watching this TV right now, previously it was a gray backlit screen and only able to turn off via unplugging it...

Mouser #: 910-SMD1
Mfr. #: SMD1
Desc.: Soldering Tools SMD Removal Kit
QTY 1 $13.50
removes u8, u2, u33, u7, u9 nicely

Mouser #: 621-AP1117E18G-13
Mfr. #: AP1117E18G-13
Desc.: Low Dropout (LDO) Regulators LDO BI 1.0A
1.3V 12V 5.0V 1.8V FIX
QTY 2 $0.44
used for u9

Mouser #: 511-LD1117ASTR
Mfr. #: LD1117ASTR
Desc.: Low Dropout (LDO) Regulators LOW DROP
FIXED REG
QTY 5 $0.91
used on u8, u2, u33, u7

Mouser #: 667-EEU-FM1E221
Mfr. #: EEU-FM1E221
Desc.: Aluminum Electrolytic Capacitors - Leaded
220UF 25V ELECT FM RADIAL
QTY 25 $0.218
used on ce75, ce8, ce7, ce14, ce16, ce91, ce2, ce1, ce5, ce6, ce23, ce11, ce27, ce18, ce25, ce26, ce20

Mouser #: 667-EEU-FR1V471
Mfr. #: EEU-FR1V471
Desc.: Aluminum Electrolytic Capacitors - Leaded
35VDC 470uF 10x16mm LS5mm
QTY 5 $0.71
used on the two inverter boards, again 3 out of four of these caps were bulging so even if yours are not currently i would suggest just replacing them to save later hassle


attached BOM for mouser as well.

regards,

TIM

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

sweet, I have 20 of the 220 uf caps so i might try replacing the rest of them, I've replaced 5 or 6 of them already and tested the caps with a capacitance meter and they all read good but i still replaced them. Haven't even looked into the inverter yet so i might try that too.

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

Well i found another board that was very very close on numbers and it looked exactly the same so i bought it. Got it put in and got the same screen except this time i could see the menu but i was still getting the vertical lines as seen in the picture above. I pulled the inverters and checked all 4 caps and they were all well within limits. They read about 476uf. Checked fuses on both inverters also. I've just about tried everything except a new panel. I'm afraid that's what it's coming down to. Also with the new board the keyboard controls were working just couldn't make out anything on the screen. SMH

[questor42]

Re: Vizio VW42L HDTV10A no picture or sound

On a capacitance meter they can measure close to their correct values But still be bad.
It happened to me, a brand new cap was bad. I borrowed a ESR meter and tested all of the caps on the power section of the board that tested good with a cap meter and found 6 that were bad.
So the can look good and test good and still be bad.

Read article at http://ludens.cl/Electron/esr/esr.html
for more info and how to build your own ESR meter

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

On a capacitance meter they can measure close to their correct values But still be bad.
It happened to me, a brand new cap was bad. I borrowed a ESR meter and tested all of the caps on the power section of the board that tested good with a cap meter and found 6 that were bad.
So the can look good and test good and still be bad.

Read article at http://ludens.cl/Electron/esr/esr.html
for more info and how to build your own ESR meter

Well now that you say that i can believe it because i just pulled 5 extremely bulged caps out of an amp and every one of them read within range. Any suggestions on an esr? I had thought about a cap wizard.

[PlainBill]

Re: Vizio VW42L HDTV10A no picture or sound

Well now that you say that i can believe it because i just pulled 5 extremely bulged caps out of an amp and every one of them read within range. Any suggestions on an esr? I had thought about a cap wizard.

Overpriced, I would have to say. If you have a good capacitance meter, the Bob Parker Blue ESR meter would be appropriate. If you need both Capacitance and ESR measurements, the ESR-Micro V4.0 is a good deal.

PlainBill

[questor42]

Re: Vizio VW42L HDTV10A no picture or sound

I agree with PlainBill they are over priced, The ESR meter that I borrowed was a cap wizard it worked well but I had to do some repairs to it before using it, The battery came out and the buzzer was loose inside shorting out on the circuit board.
There is nothing high tech inside of it to justify the cost. I am building my own with all the same features as the cap wizard.
There are a lot of choices but the Blue ESR meter is a good choice and you can save some money by getting it in kit form

[rmoody]

Re: Vizio VW42L HDTV10A no picture or sound

ok so i'm still stumped with this one. I replaced U33 and now the keyboard controls work but I still have the same vertical lines. Does anyone else have any suggestions. I also tried a replacement board from tristatemodule but it didn't change anything. I didn't check any values on that board just tried it and pulled it and sent it back. Is it possible that it could be a panel problem? Really about to pull my hair out on this one.