Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

no, it wasn't plugged in. Perhaps I'm too far out of my element. Since you described it as a fuse, I assumed a continuity test was a good way to determine pass/fail. Since I got no "beep" on continuity test, I assumed that meant it was bad. I have since desoldered that part from the power supply.

Prior to taking out F601 (ICP250 3A00SMT) I did check vdc on C104 & C105. both were equal to 0. Just to make sure I tested correctly: I was probing either leg across the (-) leg of the big 450v cap @ C608A.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

P/N of U101 SMPS IC is DA23AX Q0465R

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

If the FUSE 601 has open circuit, then there will be no voltage feeding the standby circuit.
I would remove that fuse and test it again out off the board, if it is blown open, then we will have look at a lot more components that may have shorted out.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

I've taken Part ICP250 - off board. I tested for continuity: No continuity, which means blown open, right?

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

"Part ICP250" What is the ICP250? Are you talking about the white rectangular fuse F601?

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Yes - the white rectangular fuse F601 has a p/n of ICP250 3A00SMT - sorry for the confusion.

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

OK, we need to test the 4 surface mounted devices (power MOSFETs), they have two legs on the bottom and big tab on top.
Please take the resistance readings of all four (Notes: it does not matter on the which color of the probes go to which pin because we are looking for low resistance reading).

Qxxx
1 & 2 = xx Ohms
1 & 3 = xx Ohms
2 & 3 = xx Ohms

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Q706
1 & 2 = 2.45kΩ
1 & 3 = 1.1Ω
2 & 3 = 2.52kΩ

Q707
1 & 2 = 8.4Ω
1 & 3 = 7.7Ω
2 & 3 = .9Ω

Q708
1 & 2 = 72.6kΩ
1 & 3 = .639kΩ
2 & 3 = 67kΩ

Q709
1 & 2 = 72.1kΩ
1 & 3 = .639kΩ
2 & 3 = 67.2kΩ

Q707 is not a typo; I 2x & 3x checked those readings, and kept having to change the scale on my multimeter.

Thanks again for all of your help! Tim

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Q707 is bad for sure, in this kind of circuit I would replace all 4.

[culmesm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Check power on big capacitor after that try to see if you have 5V on otput

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

@culmesm: he has blown fuse (for the B+) due to shorted out power MOSFET so there will be now voltage feeding the stby 5V power supply.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

So is my next step to purchase replacement parts for the following locations: F601 (fuse) and Q706, Q707, Q708 & Q709?

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

You should remove those MOSFETs first and then test the SMPS IC pin 1 and pin 2 to make sure it is not shorted out either.

[hdguy]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Hey guys - this is going to be a very busy week, as I get ready to leave for a week vacation to celebrate my 10 Year Wedding anniversary all next week... So I wanted to Thank YOU! for your help so far, and let you know that I'm not giving up yet!!

Thanks again! Tim

[eagle00799]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Hi guys, I been following this thread cause I have a E371VL that is quite similar and has the same symptoms-Dead. This is what I have found so far.
1. 170V across both(2) main filter caps
2. F601 fuse is blown
3. The 4 power mosfets on the bottom of the board read as follows.
Q706
1-2=10.9 ohms
1-3= .4 ohms
2-3=10.5 ohms
Q707
1-2=8.6 ohms
1-3= .4 ohms
2-3=8.3 ohms
Q708
1-2=1.12M ohms
1-3=6.6 M ohms
2-3= .63K ohms
Q709
1-2=1.10M ohms
1-3=6.6M ohms
2-3= .63K ohms

I also checked the FSQ0465RS(SMPS) in circuit pins 1&2 and got 2.1 ohms.
So besides replacing the fuse(F601) should I replace all 4 power Mosfets?

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

I would replace all 4, you should also check the set of 3 resistors and the diode that are connected to the Gate pin of each MOSFET for damage.

[eagle00799]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

The diode and 3 resistors connected to mosfet U101 are as follows
The Diode(D101)= 10.98K ohms
R104=10.98K ohms
R103=10.98K ohms
R114=10.98K ohms

[budm]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

https://www.badcaps.net/forum/attach...5&d=1412916315
I am talking about the 3 resistors and 1 diode connected to pin1 of each MOSFET.

[eagle00799]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

The 2 resistors R608-R618 are connected to Q601 fet and read 00.0 ohms

[eagle00799]

Re: Vizio E320VL - No Power, No 5v Standby - DEAD PSU??

Opps Sorry I will recheck what your asking.