Vizio SV422XVT - constant orange light

[dick_barton]

Re: Vizio SV422XVT - constant orange light

So with the main board disconnected and connecting a 1K resistor to PS_ON you definitely measured no DC voltage when you switched the set on at the 12V or 18V connections on CN201 or CN202?

[TVGuy45]

Re: Vizio SV422XVT - constant orange light

Correct, I have 5.135 on the +5v pins, 2.989V on the PS-ON pin with the 1K resistor connected, zero volts on either of the 12V pins and zero volts on the 18V pins.

[dick_barton]

Re: Vizio SV422XVT - constant orange light

OK try this. Take the PS_ON pin to GND using the 1K resistor. It could be Power ON when voltage is low.

[TVGuy45]

Re: Vizio SV422XVT - constant orange light

SO you want the resistor from gnd to the PS-ON pin correct?

Just tried that, still have my +5 but no 12 and no 18.

[dick_barton]

Re: Vizio SV422XVT - constant orange light

Yes that's correct.
Looks like a problem with the power supply.
There's a large capacitor which should be rated at 400V or more shown under the heatsink. Can you measure the DC voltage across the two legs carefully.

[budm]

Re: Vizio SV422XVT - constant orange light

Correct, there are 3 little white 5A fuses in the upper left corner, top one shows no voltage on either side,
2nd down shows 5.135 on both sides
3rd down shows 5.135 on both sides.

I did find 3 more tiny fuses with letters printed on them:
F6: K has .004VDC on both sides
F12: K has 5.132 on both sides
F11: G has 3.346 on both sides

That F6 reading corresponds to letter A voltage regulator voltage input...

I may take the board out again and investigate the backside for anymore tiny fuses...maybe do the same on the PSU board as I know theres a buncha SMD components on the backside of that too...

Powered off on ohms shows they are all good fuses with .002ohms across them.

Something is not adding up because you have 3.3V on one of the fuse, that fuse must have receiving the 3.3V from the regulator circuit some where on the main board since the power supply does not have 3.3V output pin. See if F11 has connection to the connector that goes to the power supply board.

[TVGuy45]

Re: Vizio SV422XVT - constant orange light

Alright I'll probe the other wires between the 12V and 5v pins to see if one of those happens to have 3.3V. That F11 fuse is way on the lower right corner of the board - exact opposite of the PSU connector.

[budm]

Re: Vizio SV422XVT - constant orange light

BTW, there are many threads on this TV.
I.E.
https://www.badcaps.net/forum/showth...Vizio+SV422XVT

[TVGuy45]

Re: Vizio SV422XVT - constant orange light

Something is not adding up because you have 3.3V on one of the fuse, that fuse must have receiving the 3.3V from the regulator circuit some where on the main board since the power supply does not have 3.3V output pin. See if F11 has connection to the connector that goes to the power supply board.

I have poked around for an hour now and havent found a deffinate 3.3v regulator yet. Have found 5v and 3.3 in many locations but no "smoking gun" yet...

Theres also no 3.3v signal or any signal of any kind going back to the PSU. I'm wondering if when the psu died it sent voltage out on that signal line and fried whatever sends it or vice versa...

[TVGuy45]

Re: Vizio SV422XVT - constant orange light

Alright ran thru the troubleshooting guide for the DC-DC converter diagram.

J1 Pin 10,11,12,13,14 all have 5V on them.

next step

J1 pin 1,2 do not have +12 while power switch is on/pressed.
-Connection of J1 is good
- J1 pin 17 does not have 3.3v even when power button is pressed.
-Says check power board - we know its not getting the >2v signal to turn on nor outputting 12V when forced to turn on via resistor.
- Check F4 - I have and its good via ohms (no power on either side either)

So can I even do anymore troubleshooting with a bad PSU?



Decided to just skip ahead and pretend everything above was OK

Says U1 pin 5678 should have +5 while on, 1234 on U1 have 5.1V but 5678 have no voltage at all. Pressing power button does nothing.

From the sounds of it I need both boards ($135+S&H)...

[ScottDalton696]

Re: Vizio SV422XVT - constant orange light

Hello All. Thanks for all the info. So ive got all the same symptoms on the same model unit. Wife was watching one night, walked away, heard a "POP" and came back to a black screen. Orange light,wont turn on, all fuses are good, all my 5V+ on PSU are good, no 12+ or 18+, no voltage at F4, V0 at STNBY pin with or without power button pressed. Tried the 1K resistor and jumped 5v to STNBY pin but left the cables connected. (jumped by back probing into the connector). This turned on my power supply giving me 12V+, 18V+ and obvioulsy the 12V+ at F4. Not sure where to go from here. I did check for power at the power switch. 2.8V in and 2.4V out with switch depressed. Id love to figure out what component has failed. Thanks again for the instructions.