Vizio E422VLE power supply has no 5vdc stby

[Bob Neely]

Greetings,

I picked up this TV yesterday. It was totally dead. I opened up the back and found black soot on the main board next to he HDMI receptacle and the blue connector on the Component or composite receptacle. The power supply had no visible damage. I powered it up after disconnecting everything from the power supply and I measured no voltage on the 5VDC stby pin. I checked and found voltages on the HOT side of the board but not the COLD side. I took 2 pictures to show where I had voltage and not. Can somebody point me in the right direction?

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

Pictures of the whole power supply, both sides of the board?

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

Here they are. Sending from my iPhone. Let me know if they didn't up load.

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

?????

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

Sorry. Here are the pics

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

OK, just the power supply/inverter board by itself plugged into the outlet, check the DC voltage on the TWO LEGS of the 450VDC brown main filter cap. Be careful not to touch anything since you are working on the HOT side of the circuit, the negative legs of the brown cap is the Ground ref point in the HOT side (not the chassis).
BTW, what is the P/N of the 6-pin device U101 mounted on the small heatsink?
http://www.shopjimmy.com/vizio-0500-...t-inverter.htm

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

200 VDC on C607 and C608. U101 part number is DB46BU (Q0465R).

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

On U101 I am getting:
Pin 2 (Grnd) to
Pin 1= 213VDC
Pin 3= 0
Pin 4= 0
Pin 5= 0
Pin 6= 112VDC

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

Are you measuring the voltage without any other board hooked up? if that is the case, the voltage on the cap should only be about 165~170VDC and it will jump up to about 370~400VDC when PS_ON is applied which will turn on the PFC Voltage booster circuit. Please check your meter batteries.

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

Okay, changed the batteries. I get 170VDC on those caps. I also check U101 again and pin 1 to 2 shows 170VDC and pin 6 to pin 2 shows 84 VDC.

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

OK, the IC is not switching on and off, that is why you are getting steady 170V at the Drain pin, it also has >26V @ the V start pin 6, no VCC at VCC pin. It can be bad IC or high leakage filter cap at the VCC pin. You can try replacing the 3 caps: C501, C104, and C105. You can also try heating up the three caps with hair dryer to see if the power supply will start up.

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

Replaced the 3 caps. Still no stnby 5VDC. Ordered the U101 chip from Mouser today. Will replace and update post.

[Ashroyer05]

Re: Vizio E422VLE power supply has no 5vdc stby

.

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

I replaced u101 yesterday and it didn't make a different. So, I have changed the 3 caps and U101 so far. Any ideas?

[inadim]

Re: Vizio E422VLE power supply has no 5vdc stby

Hi, Any zener in pin 3 Vcc?.

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

What voltages do you get at the IC pins now?

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

I am now getting on U101 after replacement:
Pin 2 (Grnd) to
Pin 1= 170VDC
Pin 3= .5VDC
Pin 4= 0
Pin 5= 0
Pin 6= 84VDC

What next?

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

Here are some pics. I am now getting voltage across the blue caps that go between the hot and cold side. Thanks

[budm]

Re: Vizio E422VLE power supply has no 5vdc stby

Can you take the resistance reading on the VCC (PIN3) and Ground PIN (PIN2). Something is loading down the VCC pin. I will have to look closely at the pictures around the pin 3 to see what it has connected to it.
I think I see ZD104 on the board.

[Bob Neely]

Re: Vizio E422VLE power supply has no 5vdc stby

Checked pin2 to pin 3 reads 2.1 kohms. Did a diode check and I am getting .631 with black lead on pin2 and red on pin3. I get .817 if reverse them.