Vizio GV42LFHDTV10A no pic, no sound, wont shut off

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Ok, new readouts after a fresh battery in the multimeter:

U2: 2.02 3.26 5.11
U7: 0.02 0.96 2.01
U8: 2.03 3.28 5.13
U9: 0.00 1.14 2.01
U33: 1.25 2.01 5.11

All readings were constant. None of them were jumping around.

FYI, when I retested the AA batteries from yesterday, they were the same (1.61, 1.36 and 0.51, respectively). When I tested the old battery that was in the multimeter, it read 11.42. The new multimeter battery was a 2 pack...the other new one registered 12.69 (it's a 12V).

[daimoku]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Replace U33 and it should fix your problem. Be sure to recheck U33, U7 and U9 readings afterward. U33 feeds U7 and U9. Normally, defective U33 causes U7 and U9 readings to be low

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Thanks for the feedback!

Two thing I should mention that I noticed yesterday:

1. The backlight is no longer coming aon. It was when I first starting trying to research on getting it fixed a few weeks ago. Not sure when it stopped since I've done all the testing with the panel face down.

2. On the board to the left of the mainboard, a blue light used to appear for a few seconds (or maybe longer) after the TV was powered on. It no longer lights up as of yesterday (it lit up Saturday the 23rd). The connection is labeled D1. The part numbers on the board are: 6632L-0474A and KLS-EE42-A. My good friend Google tells me this board is a Backlight Inverter, so I guess the two are related.

I tested D1 (anode to cathode) and the reading shot up to ~1.9 and then immediately back down to .0L. I reversed the test (cathode to anode) and it registered 0.

The Service Manual indicates to test these if the Backlight is not lit:
1.Check J7 PIN 14
2.Is inverter ok?
3.Is Power Board ok?

How do I properly test each of these?

[retiredcaps]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

new readouts after a fresh battery in the multimeter:

If you compare the new readings with the old readings, there is a huge difference in accuracy.

Also, I believe a battery under load conditions may be lower than just a plain DC voltage reading (with no load). So while your multimeter battery reads 11.42 with no load, it could be materially lower when used inside the multimeter.

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

If you compare the new readings with the old readings, there is a huge difference in accuracy.

Agreed.

I'm curious re this 12V. What multimeter uses this battery configuration?

It is a Radioshack 15-range multimeter, part# 22-810.

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

The Service Manual indicates to test these if the Backlight is not lit:
1.Check J7 PIN 14
2.Is inverter ok?
3.Is Power Board ok?

How do I properly test each of these?

Bump

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Replace U33 and it should fix your problem. Be sure to recheck U33, U7 and U9 readings afterward. U33 feeds U7 and U9. Normally, defective U33 causes U7 and U9 readings to be low

I went ahead and ordered part# AP1117E33G-13 from Digikey. I ordered 5, just in case.

While I wait for those to be delivered, I'd be very appreciative of any suggestions on how to test/diagnose and repair the issue of the backlight no longer lighting up. I have this eerie feeling I may have shorted something with my previous improper testing.

[daimoku]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Those are adjustable 1117 regulators. The resistors just in front of the pads are used to modify the output voltage. Digikey PN: LM1117MP-ADJCT-ND.

If you think you shorted something, I'd start with checking the two fuses on the mainboard for continuity. Also check inverter/power supply fuses too.

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Those are adjustable 1117 regulators. The resistors just in front of the pads are used to modify the output voltage. Digikey PN: LM1117MP-ADJCT-ND.

If you think you shorted something, I'd start with checking the two fuses on the mainboard for continuity. Also check inverter/power supply fuses too.

AP1117E33G-13 is fixed according to Digikey. Are you saying U33 is an adjustable regulator? If so, exactly which part(s) do I need to order? I already cancelled my first order with Digikey.

So that I don't test improperly again, can you refer me on how to properly test the fuses, and/or how to prperly test the backlight issue?

[daimoku]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

AP1117E33G-13 is fixed according to Digikey. Are you saying U33 is an adjustable regulator?

Yes, U33 is an adjustable regulator. Notice the resistors located near the pads that adjust the output voltage. The part you're looking for is Digikey PN: LM1117MP-ADJCT-ND.

So that I don't test improperly again, can you refer me on how to properly test the fuses, and/or how to prperly test the backlight issue?

First, unplug the tv and let the power dissipate for a few minutes. For fuses, you can usually just check the resistance/continuity. So, set your meter to Ohms. You should see infinite or 0L resistance when the leads aren't touching anything and ~0 Ohms when you touch the leads together.

Now, find the fuses. On the main board, there are two fuses (one for 5V another for 12V) located right by the connector coming from the power supply. Place one probe on each side of the first fuse and if the fuse is okay you'll see the meter go to ~0 Ohms. If you have a blown fuse, the meter will stay at infinite resistance or no continuity. Now move to the second fuse and check it. Be sure to check the cables too...maybe one was bumped loose and reseating it will help. Repeat this process for the inverter and let us know what you find.

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Ok, tested the fuses and here's what I found. Upon initially touching the leads to the ends of the fuses, they jumped to around 30 Ohms, and then quickly declined to 0.

On the Mainboard:
F1 - 0 Ohms
F2 - 0 Ohms

On the Left inverter board:
F1 - 0 Ohms

On the Right inverter board:
F201 - 0 Ohms

So, looks like the fuses are fine.

Should I just go ahead and replace U33 and then repost if anything else is not working?

[Dgtech]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Yes replace it

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Ok, I've got the new part, a new soldering iron, some soldering tools, and some desoldering braid.

How the heck do I get this thing off? I've tried with the desoldering braid and it took a little bit of the solder off, but the regulator isn't budging.

[nfiniti9]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

One thing you can try is to add more solder, wick it off with the braid then add a little more. Sometimes the solder is brittle and doesn't flow on the braid easily. Adding a little more will dilute it and make it flow better.

[daimoku]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Another solution that works well is the Chip-Quik alloy. It stays in a molten state long enough to desolder the 3 legs and tab easily.

Check out this video:
http://www.youtube.com/watch?v=FTQqjggeklo

Digi-Key carries it.

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Another solution that works well is the Chip-Quik alloy. It stays in a molten state long enough to desolder the 3 legs and tab easily.

Check out this video:
http://www.youtube.com/watch?v=FTQqjggeklo

Digi-Key carries it.

Bingo...my local Fry's Electronics had it. I just picked some up. I'll post my results shortly.

[ke1122]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Ugh. The new U33 is in. I reassemble, plug in the power cord and there is no "click" like there usually is, and the Visio logo on the front is not orange like it usually is. I press the power button, and nothing. No 2nd "click", no nothing.

So I unplug it, wait a few minutes and retest the fuses on the mainboard:

F1 - 0 Ohms
F2 - .0L

So, now apparently I have a blown fuse? Looks like Digikey part# F2583CT-ND.

[daimoku]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Yes, F2 is blown. Might want to purchase a couple of fuses in case another component has been damaged (when you replace the fuse, it might blow again).

F2583CT-ND is a suitable replacement as long as the physical dimensions are correct.

[Daddy-O]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Hi all...

I had the same no picture, no sound on a Vizio GV42L FHDTV10A.

The problem:

The TV will turn on with the power button or the remote. You hear a relay click and the
yellow Vizio light changes to white. A slight grey can be seen around the edges. No
picture. No sound. Press the power button or the remote and nothing happens. You have to
physically unplug the TV to power down.

After trolling multiple forums I found the best advise here at Badcaps. My mainboard is a
3642-0312-0150 (5A) and I could not find the exact board for less than $189.00. Thanks to
all of you (especially retiredcaps, PlainBill, daimoku), and countless others, you have
solved my problem for less than $25.00 and and I had an enjoyable evening of
troubleshooting. I did find a close service manual online and followed the DC-DC
troubleshooting guide but you guys here made things much simpler.

1. I determined that all of my caps were visibly good.
2. I checked the power supply fuse and all of the voltage outputs with a DVM - all good.
3. I checked the F1 and F2 fuses on the mainboard (just voltage on both side of the fuse).
4. I checked the problematic voltage regulators and had readings of:

U2 pin 2 = 3.26v - s/b 3.3v - good
U7 pin 2 = 0.99v - s/b 1.28v - BAD!
U8 pin 2 = 3.31v - s/b 3.31v - good
U9 pin 2 = 1.15v - s/b 1.5v - BAD!
U33 pin 2 = 2.02v - s/b 3.3v - BAD!

I also noticed U9 had a slight burn mark on it and I read here that U33 powers U7 and U9.

With the info I gathered here at Badcaps I ordered the following from DigiKey:

5 - Adjustable SOT-223 regulators Part #497-1229-1-ND @ $0.80 each.
2 - Fixed SOT-223 regulators Part #AP1117E18GDICT-ND @ $0.56 each.
1 - Quick-Chip SMD removal kit Part #SMD1-ND @ $13.50 each.
1 - Tweezers Part #243-1053-ND @ $4.53 each.

I chose the cheapest First Class Mail which was $2.56 and I had the parts in two business
days.

I purchased extra SMDS in case I really screwed up or there were more adjustable regulators
dead.

Since many have said U33 will solve the problem I figured on replacing it and the slightly
burnt U9 first, test the mainboard voltages, and go from there. I was able to replace the
chips with the mainboard removed from the chassis and I had plenty of room to work around
the caps without removing any.

I installed the mainboard back into the chassis and made sure to install all of the screws
in case they were needed for proper grounding. I plugged the TV in and waited a few seconds
for the first 'power off' click. Check. I pressed the 'on' button and heard the second
'click' and the buzz of the inverters. Check. I checked the voltages of all of the pin 2's
and they were ALL IN SPEC!. The moment of truth... I pressed the power button again and the
TV turned off!!!. I turned the TV back on and slid the chassis to the edge of my workbench
and I had a lovely blue screen with the 'no signal' proudly displayed! Keep in mind I had
no inputs plugged in at this time.

I just have to put the rear cover back on and hang it back on my wall. I will post if any
more problems arise and if there are more problems I will know what to look for thanks to
all of you! I expect caps next...

Thank you all so very much!

Chris (Daddy-O)

[organizddisastr]

Re: Vizio GV42LFHDTV10A no pic, no sound, wont shut off

Hello all, I am a complete noob to electronics and really want to learn. I have a Vizio GV42LFHDTV10A also with the same problem, no pic, no sound, back light is lit and wont shut off. I have read this thread and am a little lost. I tested some of the regulators with the power on and ground to one of the screws on the main board. I replaced U9 already with the correct part from digikey because when i opened up the set i saw U9 was burnt and didn't bother to test any of the other regulators. I put the set back together and same problem. I opened the set again and tested some other regulators and am getting abnormal readings on mostly all of them. U8 and U33 are giving me an open link reading on pin 3. Any suggestions would be greatly appreciated.

Here are my readings. Power on ground to screw on main board. Left to right tab on top.
U7 (Pin 1) 0.021 (Pin 2) 1.003 (Pin 3) 2.06
U9 1.10 1.10 2.6
U33 1.28 2.6 Pin 3 OL
U8 2.03 3.27 Pin 3 OL