Visio VL470M No Picture

[daniel5]

Last night we were watching tv and the picture and sound went off. It was like you put the tv in standby mode. Awhile back one of the hdmi connectors stopped working. A few months ago the remote stopped working, not sure if it's the remote or the sensor, so i've been walking to the tv like it was 1982 to change the channels/volume/etc.

So back to the main problem. I have unplugged the tv overnight and still no picture or sound. The visio on the front will light up but that is all. What do I need to check in regards to possibly determine the problem and replacing components?

[budm]

Re: Visio VL470M No Picture

It sounds like the main board problem, but first thing to do is to up load good clear pictures of the back side of the TV so we can see what we are dealing with, then good clear pictures of each board so we can give you some voltage test points to help narrow down the problem. Do you have tools?

[daniel5]

Re: Visio VL470M No Picture

Thanks for the response. I do have tools. I have attached pictures of the entire back, power board and main board.

[budm]

Re: Visio VL470M No Picture

The main board is not cheap!
http://www.shopjimmy.com/vizio-3647-...for-vl470m.htm
http://www.shopjimmy.com/media/catal...4702520150.jpg

There are some 3-pin voltage regulators on that main board that you need to check the DC voltage readings.
Please read this thread and report the readings in the format as shown.
https://www.badcaps.net/forum/showth...999#post300999

[daniel5]

Re: Visio VL470M No Picture

read through the thread and found that i shouldn't be using an analog multimeter. Guess I need to go buy a digital one before I get started.

[tibimakai]

Re: Visio VL470M No Picture

I have repaired recently one of these. It was showing the Vizio logo on the screen and then it was turning off.
I have replaced the mainboard and it was working great again.

[daniel5]

Re: Visio VL470M No Picture

Will be testing tonight. Having a hard time finding the main board for this one. Everyone seems to be out of stock.

[daniel5]

Re: Visio VL470M No Picture

Ok, here are some readings. Let me know if this is what you need or you need something different.

U8 - 0/0/0

U5
VI=6.46
vo=4.74
gnd=0

U3
VI=6.43
vo=4.69
gnd=0

U2
in=6.77
out=2.28

U6 = 0/0/0

U7
in=6.39
out=2.47

[Ltank]

Re: Visio VL470M No Picture

What are the part numbers on U2,U3,U5 and U6 ? Input of 6.46 deffinatley seems bad.
U6 is surely bad.What is the voltage from the Power supply into the mmain board? Ususally 12 vdc in gets regulated to down to 5vdc then it goes to the other voltage regulators. 3.3vdc or 2.5vdc or even 1.8vdc. The part numbers when looked up will tell you what the input range is and the what the output is supplossed to be.

[daniel5]

Re: Visio VL470M No Picture

main in is 6.60

part numbers:
U5 - L473/G1084
U3 - L473/G1084
u6 - 1117
u2 - 1117

[patrax]

Re: Visio VL470M No Picture

If your getting 12v. 5v. from the rails most definitely the main. It is probably an Ic regulator or a pico fuse on the main that is the culprit. I could never track it down and took me 4 months to get a replacement main.

[daniel5]

Re: Visio VL470M No Picture

Thanks! Did you order from "shopjimmy"? I've signed up for their email notification when the item becomes available.

[patrax]

Re: Visio VL470M No Picture

Thanks! Did you order from "shopjimmy"? I've signed up for their email notification when the item becomes available.

Yes and it took for EVER for them to finally get it in and if it wasn't for me being awake a 7am est. and getting that email I would still be waiting on the board, they had one ! I'm not sure if they are doing a send and fix,send it back but it might be worth looking into. I really don't like to deal in sensitive components from ebay but you can tske your chances there too. Good luck.

[patrax]

Re: Visio VL470M No Picture

You might also try looking at the pico fuses on the main itself. I repaired one bcuz it had one of the tiny pico's were blown probably from a voltage ripple from bad caps on the psu. It was an 11 cent fix, after replacing ALL caps on the psu. You can test continuity with a multi meter and good eyes as the pico's are tiny. I was searching Amazon today for a Samsung repair kit and I know there are some available for certain psu's for like 12$ might try that too. Digikey is also a good source for caps etc.

[daniel5]

Re: Visio VL470M No Picture

Ok guys I realized the multimeter I just purchased was defective so I purchased another. I do apologize for the faulty information and really appreciate your help! This is the correct voltages with tab up pins left to right:

U2
1117
pin 1 = 2.07
pin 2 = 3.33
pin 3 = 5.13
tab = 3.33

U7
1117
pin 1 = 2.06
pin 2 = 3.32
pin 3 = 5.11
tab = 3.32

U4
1117
pin 1 = 0.00
pin 2 = 1.24
pin 3 = 3.32
tab = 1.24

U3
L473
G1084
pin 1 = 2.06
pin 2 = 3.32
pin 3 = 5.11
tab = 3.32

U5
L473
G1084
pin 1 = 2.06
pin 2 = 3.31
pin 3 = 5.11
tab = 3.31

U6
1117
pin 1 = 0.00
pin 2 = 0.00
pin 3 = 0.00
tab = 0.00

U8
7805CT
RAE947G
pin 1 = 0.00
pin 2 = 0.00
pin 3 = 0.00
tab = 0.00

One of the LF5A fuses has 5.13 on both sides. The other has 12.26 on one side and 0.00 on other.

[daniel5]

Re: Visio VL470M No Picture

Any recommendations due to my latest testing? Due to the difficulty finding a new mainboard, I would like to try and repair this one.

[daniel5]

Re: Visio VL470M No Picture

I have confirmed that the LF5A fuse is faulty and needs to be replaced. How do I determine what fuse to buy from Digikey?

[vinceroger69]

Re: Visio VL470M No Picture

can you post a picture of the fuse you need as they come in different types etc.

[daniel5]

Re: Visio VL470M No Picture

can you post a picture of the fuse you need as they come in different types etc.

The size is roughly 1/4"x3/32". Let me know if you need a closer view. Thanks!

[budm]

Re: Visio VL470M No Picture

Just for testing purpose, you can use 5A axial lead fuse, or car fuse for now, just have to solder the wires to the legs of the fuse, then solder the wires to the blown fuse, no need to remove the old fuse, and see what you get.