Vizio vw46l blank screen issue

[darkeskye]

OK so I bought this vizio for $10.00 said it had popped and smoked. So I purchased it! Well I get the cover off and I found 1 blown and chrispy red 105k450v film capacitor, so I removed it and replaced it with the same ratings. Unit powers up and screen comes on but no picture or menu items on screen nor a vizio logo. Ive checked the board for the usual suspects but none except the one I already fixed. I have the service manual but have no idea how to use it with my multimeter. Here are some pics of the boards. Help please!

FYI the caps I replaced are the red ones in the top right corner of the board, I got desparate and replaced all the red ones and bought a cap kit from ebay and replaced all in the cap kit just to be sure and to no avail!

[budm]

Re: Vizio vw46l blank screen issue

So you do have backlights but no pictures on the screen, if that is the case, next place to look will be the T-CON board. Check the SMD fuse and DC voltage at both ends of the fuse with ref to the chassis ground.

[darkeskye]

Re: Vizio vw46l blank screen issue

and which one would that be? on the tcon right?

[budm]

Re: Vizio vw46l blank screen issue

OK F1 white fuse is on the left of the LVDS cable connector.

[darkeskye]

Re: Vizio vw46l blank screen issue

I get continuity but when i check for voltage i get 0.01 at the smd, after the smd i get 0.00 what should i do next? also there is a pin under it labeled 12v in when I check it i get 0.01.

[budm]

Re: Vizio vw46l blank screen issue

OK, that means the main board is not sending the Voltage through the switched MOSFET to the power the T-CON. You check this voltage with TV powered ON? If it is turne don, the you do have problem with the main board. The main board sends the voltage to the T-CON through the switched MOSFET.

[darkeskye]

Re: Vizio vw46l blank screen issue

yes checked while power was on, and by main board you mean the one with the tv inputers or the board that i fixed the film caps on in the first picture?

[budm]

Re: Vizio vw46l blank screen issue

The board with the input jacks. The one you fixed is the power supply-inverter combo board.

[darkeskye]

Re: Vizio vw46l blank screen issue

do people fix them? if so how would i go about checking it to find out whats wrong with it?

[budm]

Re: Vizio vw46l blank screen issue

We do try to fix them, most of them failed due to bad voltage regulators, eeprom. Anything more complicate to the point that you will need the diagrams to locate bad components is more difficult.
You can try checking the voltage regulator first, just read the thread on how to test and report the readings in the format that we can understand.
See link below my sig.

[darkeskye]

Re: Vizio vw46l blank screen issue

Already read your Guide on that! and am now in the process of getting the info to paper. Thanks a mill, in a few min i will have my findings.

[budm]

Re: Vizio vw46l blank screen issue

Looking at the picture, U37 (to the left of the LVDS connector of the main board) is the Switched MOSFET that supply the voltage to the T-CON board.

[darkeskye]

Re: Vizio vw46l blank screen issue

ok here is what i checked so far:
F1 fuse Start:4.99 Ends 4.96
F2 Fuse start:11.98 Ends 0.002

And I checked the larger voltage regulators (u20, u21, u17, u19, u15, u22, u44, q19 ,u16)

u16 is the only large voltage regulator reading 0.000 (far top right corner of board)

I will check u37 now!

[budm]

Re: Vizio vw46l blank screen issue

Fuse 2 for the 12v to power the audio amplifier and the T-Con is blown. That explain why you do not have 12V for the T-CON.

[darkeskye]

Re: Vizio vw46l blank screen issue

ok i checked u37

Starting from pin 1 (bottom left corner and going up)
Pin1 0.0014
pin2 0.003
pin3 0.0016
Pin4 0.003

Pin5 0.000 (location is top right leg)
pin6 0.000
pin7 0.000
pin8 0.000

Whats this mean?

also I checked the voltages of the cable running directly from the psu board to the main board and they are getting the voltages labeled for them so i know its getting power.

[darkeskye]

Re: Vizio vw46l blank screen issue

so replace fuse f2?

[budm]

Re: Vizio vw46l blank screen issue

Check the resistance between the end of the fuse that shows no voltage and the chassis, report the reading.

[darkeskye]

Re: Vizio vw46l blank screen issue

I replaced the fuse before I got or last message. I actually see something now but there are vertical lines. Here's a pic

[darkeskye]

Re: Vizio vw46l blank screen issue

Also the image flickers.

[budm]

Re: Vizio vw46l blank screen issue

Try re-seating those 4 flat ribbon cables between the T-CON and the LCD panel.