Vizio E472VL

[ljintexas]

Totally devoid of lights or life. Friend stated that during a storm, both TVs went out. Satellite provider had to replace complete dish and both receivers. Nothing else in the house was affected. Not computers that were running nor appliances.
All visible fuses and MOV check good. Possibly lightning? Coax is properly grounded and was not just done recently..#10 AWG solid copper bonded to telco ground rod.
Disconnected cable to main board. I have 5 volts dc at all three pins on PS, but no 12 volts. Grnds have continuity to ground. No visible damage to front or back side of SMPS. Have not removed main board to look at back side.

Help!

Thanks

[paulstef]

Re: Vizio E472VL

Are fuses on mainboard (right next to the connector) ok too?

The 12V are probably switched on when the TV is turned on. . Do you have a standby light? Does it change when trying to turn the TV on? What are the voltages on the connector going from PSU to mainboard? Specifically the PS_ON, BL (or similar) signals.

[ljintexas]

Re: Vizio E472VL

Will look again but did not see any lights, report back tonight.Will check voltages with cable connected

[ljintexas]

Re: Vizio E472VL

No standby light..No sign of a light..not the VISIO or any light for that matter. Yes all fuses are good. with main boards connected, no voltage on anything except 5 volt pins..they drop down to .2 volts..and stay there even when main board is disconnected..cycle power with disconnected and 5 volts comes back. I am sure main board is toast, but wish I knew is PS was supposed to generate 12 volts in standby.

[budm]

Re: Vizio E472VL

12V will not be present until the main board sends out the PS-ON signal top the PS-ON pin on the power supply board.
Report each pin names and Voltage reading when TV is off and when power switch is activated.
I.E.
Pin 1 xxxx, TV OFF= ????VDC, TV ON = ???? VDC

[ljintexas]

Re: Vizio E472VL

Listed measured voltages on 14 pin connector for cable from smps to main board. The first number is 120v plugged in no main cable on smps. Second number is plugged in with cable plugged into smps and mainboard. Last number is same but turned on via on/off switch..last column is how they are labeled.

pin 1 5.2v .459v .368v +5V
pin 2 5.2 .462 .371 +5V
pin 3 5.1 .465 .385 +5V
pin 4 0 0 0 GND
pin 5 0 0 0 GND
pin 6 0 0 0 GND
pin 7 0 0 0 GND
pin 8 0 0 0 12V
pin 9 0 0 0 12V
pin 10 0 .02 0 12V
pin 11 0 .06 0 Standby
pin 12 0 0 0 ON/OFF
pin 13 0 0 0 Status
pin 14 0 0 0 DIM

[budm]

Re: Vizio E472VL

OK, the +5V (Standby Voltage) is basically dead, without it, the TV will not do anything.
So you need to find out why it is dead, it will involve check Voltages on the HOT (DEADLY side) of the power supply board.
More likely the main board may also be damaged since the St box connected to the TV input was also damaged.
Right now you can try disconnecting that cable going to the main board and see if you will get +5V back, it may be loading down by the bad main board.

[ljintexas]

Re: Vizio E472VL

The 5 volts will come back if I disconnect the main board and cycle power.

[budm]

Re: Vizio E472VL

The 5 volts will come back if I disconnect the main board and cycle power.

OK, put the connector back in place and then check the resistance beteween the +5V pin and the chassis to see if it shows very low resistance.

[ljintexas]

Re: Vizio E472VL

With power off, correct?

[budm]

Re: Vizio E472VL

With power off, correct?

Power cord removed from the AC outlet and wait for about 5 minutes to let the main cap discharged.

[ljintexas]

Re: Vizio E472VL

all three +5V pins show 1.45 Meg ohms to chassis after 5 min of separation from 120 volts.

[ljintexas]

Re: Vizio E472VL

I would have thought +5v pins to chassis would have shown low resistance..let me do some more poking around with meter. Is there a way to supply 5 v to smps to see if it comes up and possibly test outputs?

[budm]

Re: Vizio E472VL

The over current draw problem can be from the load connected after the regulator or after switching device that has to be turned on after 5v is applied.
The +5V is the standby power supply that is present the minute you plug the TV power cord into the wall outlet, you can test the +5V using resistor dummy load,
5 Ohms will draw 1A (5Watt), 10 Ohms will draw 0.50A (2.5W) so you can try 10 Ohms first to see if it can handle 0.50A.

[johnp1214]

Re: Vizio E472VL

I have a vizio E422vl that powers on and off manually. But screen is pure white with mainly black and some colored vertical lines. Apparently it was struck by lightning I received free from friend in hopes of fixing it. Any ideas ?

[ljintexas]

Re: Vizio E472VL

The issue was the main board. Replaced and up and running like a new one.

Thanks for your help.

[newtothis]

Re: Vizio E472VL

Cheers for the update