Vizio vx32l black screen no backlight

[ricosavy]

I have Vizio 32 model vx32l at first the tv had no voltages coming out from power supply to main board.I found it had a bad fuse one of those round ones 5a 250v.I replaced it and now I am getting 5v to my main board.There are two fuses on main board one has 5v when tv is pluged in.when I power the tv on the other fuse is suppose to have 12v but it has nothing.It looks like the power supply is not putting out 12v.I am thinking something in the power supply took out the main fuse that I replaced.If any one has any idea or a schematic of the power board so I can trouble shoot it.i have not been able to find one the service manual I have downloaded does not have the schematic.I know the sell a repair kit for power supply so it may be a common problem.Thanks

[nomoresonys]

Re: Vizio vx32l black screen no backlight

are you checking the fuses with your meter in diode mode?, should read 000 or close to it, if you get ol or no change on meter then it's probably bad, can you post some good clear pics. of the boards, careful when working with power supply "HIGH VOLTAGE".

[ricosavy]

Re: Vizio vx32l black screen no backlight

i am at work soon as i get home i will post picture.i desoldered the fuse and checked it and it was ol put new on in.i am thinking a power mosfet or something in the ac line is shorted.will post pics soon as i can.

[nomoresonys]

Re: Vizio vx32l black screen no backlight

if you turned it on and your new fuse didn't blow thats a good sign.

[budm]

Re: Vizio vx32l black screen no backlight

"There are two fuses on main board one has 5v when tv is pluged in.when I power the tv on the other fuse is suppose to have 12v but it has nothing.It looks like the power supply is not putting out 12v.I am thinking something in the power supply took out the main fuse that I replaced.If any one has any idea or a schematic of the power board so I can trouble shoot it."
The power supply is not going to put out the switched 12V, 24V (if power supply is OK) until it gets the PS_ON signal from the main board.
You need to verify if you have PS_ON (>2.5VDC) or not when power switch is activated. These VIZIO are known for having bad Voltage regulator ICs on the main board.
Please read 'Basic LCD TV and Monitor troubleshooting guides.'

[ricosavy]

Re: Vizio vx32l black screen no backlight

It tried the light bulb trick the light stays on for about a minute then turns off.I think that is what is saving my fuse from blowing.budm I will check my ps-on to see if I have any voltage.

[ricosavy]

Re: Vizio vx32l black screen no backlight

I don't know how I missed this.looks like something shorted out.i place the power supply back to see where short matches the board.and it is on a bolt that holds a heat sink into place the middle on to be exact.the only two components I see on the chip are q10 and q2 part number k2843.Look at pics.thanks

[ricosavy]

Re: Vizio vx32l black screen no backlight

Other pic

[budm]

Re: Vizio vx32l black screen no backlight

I don't know how I missed this.looks like something shorted out.i place the power supply back to see where short matches the board.and it is on a bolt that holds a heat sink into place the middle on to be exact.the only two components I see on the chip are q10 and q2 part number k2843.Look at pics.thanks

I cannot tell from the picture, it is too out of focus for me to see.

[ricosavy]

Re: Vizio vx32l black screen no backlight

Well here is a lesson learned maybe it was a power surge or who knows.I took out the heat sink since it is just screwed and u soldered the mosfets.They tested ok in diode mode they would switch on and off and where not grounded.The main fuse was bad.but everything seemed ok.I could here the power supply switch on.I Checked the power switch power it was low then when I powered on it would raise to 1.7volts then it was gone.I keep on noticing that my light bulb would go bright then it would cut off every time I hit the power switch.I started thinking this light bulb is acting like tv when turn it off then it shuts off.So I took thing off my power cord and hooking power direct to the wall.bingo the tv turned on.I am guess some how the bulb was taking away power from tv and the protection circuits where kickin in.Maybe bulb to small 60watts or new gf outlet on the set up.Tv is up and running will just have to see if fuse will blow again.For now time to enjoy tv.😄

[ricosavy]

Re: Vizio vx32l black screen no backlight

Pic

[ricosavy]

Re: Vizio vx32l black screen no backlight

Picture

[budm]

Re: Vizio vx32l black screen no backlight

You use 60~75W for checking when TV is in standby to see if the bridge rectifier, the STBY power supply are OK or not, to go full power you will need at least 150~200W.

[ricosavy]

Re: Vizio vx32l black screen no backlight

Budm,Thanks did not know that.

[budm]

Re: Vizio vx32l black screen no backlight

One of my short indicator has two lamps sockets so I can easily add the lamps as needed.

[ricosavy]

Re: Vizio vx32l black screen no backlight

Nice,you have a diagram how you wired it would be good.