Vizio E28H-C1

[Fisher77]

This is the last TV that took a lighting strike from my parents house.
Power supply has no output voltage. I have replaced a blown diode, blown FET, blown resistor, PWM, and 2 caps.
I still have 0V on all the outputs of the PS board.
Power supply board number is PLTVEF201XAF5. I have outlined all the components replaced
in red boxes on the pics. I also posted a pic of the PWM pinout, and a
schematic it was used in. The schematic does not belong to this TV.
I was unable to find a datasheet on this particular PWM. It is a PF6003AHS.
The FET is a K8A50D. Resistor is a 0.27 ohm 1W. Diodoe is a SR5150.
Caps are both 10uF 50V.

If there are any other pictures needed let me know, and I will
post them. I really don't know what else to check.

Thanks for any help.

[dskall]

Re: Vizio E28H-C1

Your fuse is good? What do you have across your main filter cap?

[dick_barton]

Re: Vizio E28H-C1

I would also check that the PF6003AHS has no short circuit to the ground pin (Pin 4)

[Fisher77]

Re: Vizio E28H-C1

Your fuse is good? What do you have across your main filter cap?

Thanks for the reply Dick_Barton

Checked all the fuses, they are good. 164V DC across the main filter cap.

I would also check that the PF6003AHS has no short circuit to the ground pin (Pin 4)

Will do.

[dskall]

Re: Vizio E28H-C1

Voltage on pin 8 of PF6003AHS? If you have oscilloscope you could check input to fet. Any output from transformer? Resistors and diodes good around PF6003AHS?

[Fisher77]

Re: Vizio E28H-C1

Voltage on pin 8 of PF6003AHS? If you have oscilloscope you could check input to fet. Any output from transformer? Resistors and diodes good around PF6003AHS?

The resistors and the diodes around the PF6003AHS have all checked good. The voltage to the Drain of the fet is 164V. I will check the transformer output.

When checking the voltage on pin 8 of the PWM, do I use the negative of the main cap for ground?

I checked the PWM, and did not find a short to ground.

[dskall]

Re: Vizio E28H-C1

Everything on hot side of line is neg of main cap or neg of bridge rect. or #4 ground pin on ic

[Fisher77]

Re: Vizio E28H-C1

Ok, voltage on the PWM pins is as follows

1 .636V
2 0V
3 .687V
4 0V
5 0V
6 4.62V
7 NC
8 4.62V

[dskall]

Re: Vizio E28H-C1

Seems like there should be something on feedback #2

[Fisher77]

Re: Vizio E28H-C1

Seems like there should be something on feedback #2

I agree. The trace for #2 runs trough a couple of 0 ohm resistors to pin 4 of the optocoupler.

Possible bad optocoupler?

[CapLeaker]

Re: Vizio E28H-C1

Also check R9112, 13 and 14 (three resistors in series).
Can you upload the whole schematic, please?

[dick_barton]

Re: Vizio E28H-C1

I would think that the VCC supply for the PWM is low especially when you consider there a 50V capacitor attached to it.
Check the resistance of R9111/R9112

[CapLeaker]

Re: Vizio E28H-C1

I would think that the VCC supply for the PWM is low especially when you consider there a 50V capacitor attached to it.
Check the resistance of R9111/R9112

R9111 and R9102

[dskall]

Re: Vizio E28H-C1

He says that schematic is not for his tv. Just that the schematic has the same controller. So more like a generic circuit. Also can't find spec. sheet for that controller.

[Fisher77]

Re: Vizio E28H-C1

I checked all those resistors, they all check good with the leads one way, but if I reverse the leads the meter jumps all over the place.

I checked R9113 also. Something wierd going on there too. When I check it one way its shows 4.29M, when I reverse the leads it shows 14.53M.

WTH is going on here?
Something in circuit causing this?

He says that schematic is not for his tv. Just that the schematic has the same controller. So more like a generic circuit. Also can't find spec. sheet for that controller.

I have searched for a datasheet to, no luck. I contacted the seller of the chip to see if he had one, no dice. So wonderful to deal with these "grey market" components.

[dick_barton]

Re: Vizio E28H-C1

Check the resistors leading from AC-1 that feed BNO. I have had one resistor go high and stop the set from working, but was on a different set. The only way to tell was to lift them off the board and measure.
It looks like BNO may be acting as the AC Detect input.

[budm]

Re: Vizio E28H-C1

So what is the real P/N of the SMPS IC U9101?

[Fisher77]

Re: Vizio E28H-C1

So what is the real P/N of the SMPS IC U9101?

PF6003AHS is the number that was on the original

[Fisher77]

Re: Vizio E28H-C1

Ok, I replaced the PS board. The TV will still not power on.

Voltages on the PS board are:
On/Off - 0V
DIM - 0V
PS_ON - 0V
12V_A - 12V
+12V - 12V
+12V - 12V
There are a total of six 12V pins on the PS board. All 6 have 12V.

I checked the voltages on the main board plug that go out to the
on/off button, and the IR sensor board.

They are as follows by wire color:
Gray - 0V
Purp - 5V
Blue - 5V
White - 3V
Green - 0V
Yellow - .8V
Orange - 0V
Brown- fluctuates anywhere from 0V to .8V.

Black and Brown wire go to the on/off switch. The rest go to the IR sensor board.

[dskall]

Re: Vizio E28H-C1

Do you get anything on pson when you push power button? Backlights? Check around mainboard input connector for fuses, voltages at regulators. Brown wire fluctuates when you push power button?