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

[budm]

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

Where is this Q601? I do not see it in the picture.

[eagle00799]

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

Q706
R710=10.5 ohms
R752=11.6 ohms
R701= .200K ohms
D751= .210K ohms

Q707
R759=9.1 ohms
R713=8.1 ohms
R704= .200K ohms
D755= .208K ohms

Q708
R723=3.63K ohms
R756=3.63K ohms
R707= .200K ohms
D753= .835K ohms

Q709
R726=6.37K ohms
R762=6.36K ohms
R711= .200K ohms
D753= .835K ohms

[eagle00799]

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

Q601 is on the big heat sink

[eagle00799]

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

2nd one up and the 2 resistors across from it

[budm]

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

Q706
R710=10.5 ohms
R752=11.6 ohms
R701= .200K ohms
D751= .210K ohms

Q707
R759=9.1 ohms
R713=8.1 ohms
R704= .200K ohms
D755= .208K ohms

Q708
R723=3.63K ohms
R756=3.63K ohms
R707= .200K ohms
D753= .835K ohms

Q709
R726=6.37K ohms
R762=6.36K ohms
R711= .200K ohms
D753= .835K ohms

Looks to me that the resistors for the Blown Q706, 707 are also damaged.
You should be able to read what are printed on the top of the resistors which will tell you what they should be. You show D753 twice, I would removed those resistors, diodes for Q708, 709 and test them off the board. I will not be surprised that they are damaged.

[budm]

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

BTW, The reading on Q706, 707 are taken with the MOSFETs removed?

[eagle00799]

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

Sorry the Q709 diode should be D757.
All the mosfets are still in place on the board. Should I remove all 4 then recheck them and remove all the resistors and diodes?

[budm]

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

I would remove those two MOSFETs (Q706, 707) that tested bad first, but you should also read the numbers as printed on top of the resistors to verify the resistance.

[eagle00799]

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

Wow those are hard to read(tiny). I believe they say
Q709
1007
681
2000

Q708
1002
681
2000

Q707
681
1002
2000

Q706
1002
681
2000

[budm]

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

1007 is more likely to be 1002?
I expect the resistor connected directly between the Gate and the Source pin to be around 10K (1002).
It is going to be hard to verify the value when they are on the board since there are other components connected in parallel with the resistor you are trying to measure.
If you remove all 4 MOSFET, then you may be able to do comparison readings.

[eagle00799]

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

Ok thanks Budm for all your help. I will remove them and check them tomorrow.

[eagle00799]

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

I removed the 4 mosfets and did a resistance check on all the resistors and diodes still on the board and I rechecked the mosfets once I removed them and this is what I got.
Q706
1-2=14.6
1-3= .5
2-3=14.0
R710(1002)=.636K
R752(681)= .636K
R701(2000)=.200K
D751=.836K

Q707
1-2=9.7
1-3= .4
2-3=9.4
R713(1002)=.636K
R759(681) =.636K
R704(2000)=.200K
D755=.836K

Q708
1-2=OL
1-3=6.60M
2-3=OL
R723(1002)=.636K
R756(681)=.636K
R707(2000)=.200K
D753=.836K

Q709
1-2=OL
1-3=6.98M
2-3=OL
R726(1002)=.636K
R762(681)= .636K
R711(2000)=.200K
D757=.836K

[eagle00799]

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

Does it appear that Q706 & Q707 are bad? What would be a good replacement for these KF5N50's?

[budm]

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

Q706, 707 are bad for sure.
The resistance will be tough since the Gate drive transformer winding is basically in parallel with the resistors, the only sure way is to remove the resistors and test them off the board, I would remove the resistors for Q706 first since we know that Q706 is damaged, if the resistors tested OK then more likely the resistors for the Q707 will be OK too.
Q708, 709 are not shorted out so the resistors and the diodes are probably OK.

[eagle00799]

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

Ok I will take the resistors off of Q706 and get back to you.

[eagle00799]

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

Q706
R710(1002)=10.00K
R752(681)= 6.80K
R701(2000)=.200K
Well these appear to be good,Should I remove the diode also?

[budm]

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

681 should be 680 Ohms.
http://www.resistorguide.com/resistor-smd-code/
http://www.marsport.org.uk/smd/res.htm

[eagle00799]

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

I did find a good replacement for the cement fuse F601 ICP250/3A00SMT = TWW5JR15E but I cant find the equivilant to the 4 KF5N50's.

[eagle00799]

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

Sorry my bad, should be .680k

[budm]

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

http://www.shopjimmy.com/kec-kf5n50d...tor-3-pack.htm