Vizio VW42LFHDTV10...Brother Mikes TV...

**kingofcoins** · 01-28-2011, 11:19 AM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...parts are in

Bill and others....My digi-key parts are in (under 40 hours from on line click...how do they do that for $2.12 shipping? !!)
Awaiting your further instructions on testing, checks, steps prior to installing the new 1117 regulators on the board...any ?

**Dgtech** · 01-28-2011, 11:25 AM

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

I say go for it. Before power up, check all that you've touched and done. Make sure all is secure and connected. Good Luck and report back.

**PlainBill** · 01-28-2011, 12:46 PM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...parts are in

Originally posted by kingofcoins

Bill and others....My digi-key parts are in (under 40 hours from on line click...how do they do that for $2.12 shipping? !!)
Awaiting your further instructions on testing, checks, steps prior to installing the new 1117 regulators on the board...any ?

1. I suspect Digikey has an automated parts pulling system.

2. The US Post Office is the butt of a number of jokes by those with weak minds. The fact is they are committed to delivering First Class Mail anywhere in the country within two days. Even to an Indian tribe at the bottom of the Grand Canyon. For more routine deliveries, a highly automated sorting system helps.

PlainBill

**kingofcoins** · 01-28-2011, 01:46 PM

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

Bill...
Should I test new regulators before I install ?
What did you think of that 7.5v out I got on the old ones ?
Any other checks tests before proceeding ?

**PlainBill** · 01-28-2011, 05:25 PM

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

Originally posted by kingofcoins

Bill...
Should I test new regulators before I install ?
What did you think of that 7.5v out I got on the old ones ?
Any other checks tests before proceeding ?

I seldom bother testing new components. If you have a breadboard, setting up a test jig is fairly easy. You will need two resistors, ideally two resistors of 150-500 ohms and of equal value.

Note the application circuitry for the AMC1117 on page 6 of the datasheet. You can do a 'stripped down' version of that circuit. Don't bother with the caps, and substitute one of the fixed resistors for R2, the variable resistor. The other resistor is used for R1, of course. Apply 9V to the input, the output should be 2.5 volts.

PlainBill

**kingofcoins** · 01-29-2011, 01:13 AM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...LDO regulator test

Bill....I'm still not clear on testing these regulators and interpreting the results. Attached my pic shows the layup I ran with 2 resistors and the battery...I tested Vout as the probes show from pin 2 to the battery ground. My battery measures 8.7V, and two identical resistors read 480 ohms each. Vout I get now is 6.5V, whereas it was reading 7.5V without the resistors.
Is this test correct ?
And if so, what do these high voltages mean ?
I got that same 7.5V on the new regulators as those I pulled.

Attached Files

**PlainBill** · 01-29-2011, 08:16 AM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...LDO regulator test

Originally posted by kingofcoins

Bill....I'm still not clear on testing these regulators and interpreting the results. Attached my pic shows the layup I ran with 2 resistors and the battery...I tested Vout as the probes show from pin 2 to the battery ground. My battery measures 8.7V, and two identical resistors read 480 ohms each. Vout I get now is 6.5V, whereas it was reading 7.5V without the resistors.
Is this test correct ?
And if so, what do these high voltages mean ?
I got that same 7.5V on the new regulators as those I pulled.

As far as I can see, the test setup is correct. The only 'error' is for this part pin 1 is called Adj, not Gnd. The soldering looks like something I would do on a test setup.

The resistance values are higher that specified, but I'd have to review the datasheet carefully to see if that could be a problem. I wouldn't think so, it implies a great deal of current out the Adj pin.

Here are a couple of ideas to try. Try adding a 100 ohm resistor as the load. Recheck the solder joints. I can't be the only person who had what looked like a perfect joint that turned out to be open. Hook caps across the input and output. If you have them available, parallel the existing resistors with one more each - this would have the effect of dropping them down to 240 ohms.

Electronics hell has been described as when the parts test perfect, but the assembly won't work. You seem to have electronics purgatory - you can't get the parts to test perfect.

PlainBill

**kingofcoins** · 01-29-2011, 08:34 AM

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

As always Bill Thanks for the replies...
Now for the moment lets call my new parts good, what do you think the prognosis is if I install the new regulators...did we find 'anything' bad with U7 and U33 ?
What should I do next...?
I have pulled 3 more of the caps associated with the other regulators, and all 3 read 0.35 ESR for 220ufx25V, and one read only 195uf.

**PlainBill** · 01-29-2011, 11:03 AM

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

Originally posted by kingofcoins

As always Bill Thanks for the replies...
Now for the moment lets call my new parts good, what do you think the prognosis is if I install the new regulators...did we find 'anything' bad with U7 and U33 ?
What should I do next...?
I have pulled 3 more of the caps associated with the other regulators, and all 3 read 0.35 ESR for 220ufx25V, and one read only 195uf.

The voltage out of the original regulators was strange. Either they were defective, or they were limiting the output voltage because of excessive current. If you had a lab supply I would have suggested using that to provide an 'assist'. As it is, replacing the regulators is the best approach.

PlainBill

**kingofcoins** · 01-29-2011, 11:41 AM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...2 more

Ok couple more things....
1). Should I be pulling and replacing these Taicon P SERIES 220UFX25v lytics, all of which I've pulled so far (8 of 9) read 0.35 ESR @ 215uf ..?

2). I did one more check on the regulators with two 95 ohm resistors in the test circuit and got 4.4V out...so it was 7.5v with no resistors, 6.5 with 480 ohms, and now this, so I've bracketed the 125 ohms they wanted but still we got nowhere close to the 2.5V spec...so is this 'purgatory' ...and lets' see what the installed parts , do or what ?

**PlainBill** · 01-29-2011, 05:23 PM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...2 more

Originally posted by kingofcoins

Ok couple more things....
1). Should I be pulling and replacing these Taicon P SERIES 220UFX25v lytics, all of which I've pulled so far (8 of 9) read 0.35 ESR @ 215uf ..?

2). I did one more check on the regulators with two 95 ohm resistors in the test circuit and got 4.4V out...so it was 7.5v with no resistors, 6.5 with 480 ohms, and now this, so I've bracketed the 125 ohms they wanted but still we got nowhere close to the 2.5V spec...so is this 'purgatory' ...and lets' see what the installed parts , do or what ?

1) I would. Taicon does not have a stellar reputation. I haven't found information on their P series (possibly obsolete), but their PZ series shows an impedance of .11ohms at 100Khz. Someone else knows better than I do how that translates to ESR.
2) Might as well. I don't understand what is going on there.

PlainBill

**PlainBill** · 01-30-2011, 04:00 AM

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

"Upon further review", I retract my advice about replacing the caps - for now. I instead suggest they be replaced before 'buttoning up' the TV.

The output voltage of the regulators was 'unusual', and could have prevented the TV from working. The caps are very unlikely to be responsible for the unusual voltage. So replace the regulators, test the TV. If it works, go ahead and replace the caps. If it doesn't work, replace the main board.

PlainBill

**kingofcoins** · 01-30-2011, 08:01 AM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...>SUCCESS !!!

Hey look what I did

with YOUR help

Put in the two new LDO Voltage Regulators at U7 and U33, and 5 more 220uf caps near them on mainboard...I kept thinking it won't work, it won't work, .. and viola, it DID !

Stay tuned..> I'll get a review summary posted when time permits, pic....

Attached Files

**Dgtech** · 01-30-2011, 08:08 PM

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

Nicely done!! Congrats!!

It feels good, doesn't it? You saved yourself a good bit of money and you had fun with it too, I'm sure. I'm a huge plainbill fan myself as well. Good luck on your next project.

Hey, enjoy the big game next weekend.

**kingofcoins** · 01-31-2011, 08:03 AM

Re: Vizio VW42LFHDTV10...Final Repair De-briefing

Here's the executive summary of the problem, analysis, and successful repair of the Vizio VW42LF HDTV10:
Set had no lights, no sound, no video, doesn't respond to on/off switch, only see the amber logo and clicking heard from Power supply when plugged in.
Set has 5 boards...T-Con at top, power supply, mainboard at bottom, and an inverter board at each side...see post #1 for pics.
Repair Sequence.....
Basic problem(s), symptoms... read Post # 21
Basic set theory, Power Supply......Post # 8 & 9
Inverter Board Checking....see # 32 & 62
Re-analyses...read #64
Mainboard and final repairs...see Posts #65, 68, 70, 75-77, and 89 & 90

Service Manual location:

Thanks so Very Much To ALL who helped on this project. I will report back any further repairs if needed.
SB XLV Outcome..>

Steelers 21 Packers 17

**dossman** · 02-23-2011, 07:49 PM

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

I'm working on a visio VX42LHDTV10A but I can't seem to download the service manual from this link.

**Scenic** · 02-23-2011, 08:37 PM

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

that site doesn't seem to like any proper browser..
doesn't show a download link at all in Opera (plus totally messed up layout).. works fine in IE.. go figure

same file reuploaded to my webspace:

**turbozutek** · 02-24-2011, 03:55 AM

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

Originally posted by Scenic

same file reuploaded to my webspace:

On reviewing the manual, I especially liked the 'BOLLOCK DIAGRAM' - anyone with a grasp of British English will understand why this is so important when attempting to debug a TV that's balls to the wall!

Chris...

**kingofcoins** · 02-24-2011, 07:11 AM

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

I replaced 8 more of the main-board caps that had moderately high ESR's on principle that the Taicon's, series VT & VZ are not the best..that makes 18 total, mostly 200uf x 25v replaced on this board
Now a very happy Brother Mike reports that he thinks TV looks and sounds 'better than new'.
If you need help with a Vizio that's not a 42 inch LCD, please search the forum or start a new thread.
Again Thanks to All !

**cadillacman** · 02-25-2011, 12:26 AM

Re: Vizio VW42LFHDTV10...Brother Mikes TV...>SUCCESS !!!

Originally posted by kingofcoins

Hey look what I did

with YOUR help

Put in the two new LDO Voltage Regulators at U7 and U33, and 5 more 220uf caps near them on mainboard...I kept thinking it won't work, it won't work, .. and viola, it DID !

Stay tuned..> I'll get a review summary posted when time permits, pic....

WOW!! Been reading through this post, i admire your shear willpower and unwillingless to give up!
AWESOME!!!

Vizio VW42LFHDTV10...Brother Mikes TV...

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