Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400i-B2

[S.gilletly]

I am currently attempting to fix my TV and my sisters TV. I recently took voltages from my sisters E400i-B2 vizio power supply. I accidentally touched multiple pins with my lead on CN201. Pins 7-12v and 8 -12v where both reading between 10-10.8vdc when powered on. since I touched multiple pins at once and caused a quick arc the same pins are now reading 3.7dvc when on and off. I'm lost at this point. Any information would be great. thank you

[budm]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

1) We need god clear hi-res pictures so we can what we are dealing with.
2) We need to know what the TV's are doing or not doing before you start working on them.

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Sorry for the late reply. I have attached pictures to my sisters vizio E400i-B2. The readings I'm getting both on and off are listed below. However, prior to touching my multimeter lead to pin 7 and 8 at the same time I was getting 10dvc on all the 12v pins.

Readings on multi meter on and off
5-vsb 5v
5-vsb 5v
ACDET 3.2v
PSON 2.9v
GND zero
GND zero
12v 3.7v
12v 3.7v
GND zero
GND zero
12v 3.7
12v 3.7
nc
nc
nc

By the way i'm only looking to replace entire boards for this project maybe that will be easier to narrow down the cause.

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Oh I forgot to mention that prior to me testing the TV the reason why I began to troubleshoot was the TV stopped Turning on.

[vinceroger69]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

can you also take a good clear picture of the underside of the power supply so we can see the traces and components on it thanks.

[jetadm123]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

The black connector at the top of your power supply is 24 volts. What are you reading for that?

[R_J]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Check Q202, located on the back of the board near CN201, it may be open You could also check the voltage on D202 (center pin) and see what that voltage is

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Hey once again my apologizes for the delayed response. I was at work. @Jetadm123 the black connector is reading 25.6dvc. @vinceroger69 I have also uploaded a picture of the underside of the power supply. @R_J for Q202 11.85dvc and D202 11.86dvc

[R_J]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Q202 has 3 (2 small plus the tab) legs, I can't read the number on it but if you have close to 12 volts on the small leads and nothing on the tab that goes to the connector, I suspect the transistor/fet is open.

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

i have close to 12 volts on the small leads and about 3.66 volts on the tab. When you say you suspect the transistor/fet is open. I actually have no idea what that is. I'm a novice when it comes to all this however, is this somthing that is related to the power supply?

[R_J]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

That black plastic part with the 2 legs and the tab, I suspect it is bad. It has a number on it... what is the number on it?
I suspect it is a mosfet

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

B16 P04 EG 2520. does this sound about right ?

[R_J]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Yes it's a fet, the full number would be EMB16P04A
12 volts enters the source pin and when the gate gets turned on (which it is) 12 volts will be at the Drain. Its basically a switch
I guess its possible something is loading the 12 volt line down but since you shorted that line I would bet on the bad fet

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

do you feel this will fix the powering on issue or just fix the voltages on the CN201? as i described before I caused an arc by touching two of the 12v pins which caused the voltages to go from 10volt to 3.7volt?

[R_J]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

Replacing the fet should get you back to where you were before shorting the pins
Did the tv try and turn on? ie did the power led come on?
Did you have any sound? or backlights?
I suspect if you were getting 12 volts (or 10v) and also had +24 volts, the power supply was working and the power supply WAS getting the power on command from the main board
The 12 volts being low could be due to poor C228, C229 or C206
Being that this is a @$%^ vizio, I might suspect the eeprom

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

thank you

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

i will update after i'm done.

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

there was no sound and the power led would not light up

[S.gilletly]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

is vizio known for having faulty eeproms? also what happens when an eeprom goes bad?? like what are the tv symptoms usually ?

[R_J]

Re: Accidentally touched multi meter lead to multiple pins on power supply.Vizio E400

If the eeprom goes bad usually you can't turn on the tv, or maybe the led will come on but thats all. The eeprom contains the proccessor code and if it gets corrupt or cant be read the microprocessor does'nt know what to do.
Did the tv show any signs of life before the short?