Vizio E321VL dead blown fuse

[ivtec]

Hi guys;i found this Vizio E321VL and it's dead no Vizio logo,opened it up and found 3.5 amp 250 v fuse blown,before i replace it, is there anything else that might gone bad with the fuse that i should look over?thanks ,

[petehall347]

Re: Vizio E321VL dead blown fuse

look for shorted components like fets and diodes for starters

[heavymachines]

Re: Vizio E321VL dead blown fuse

Check for shorts at fuse to ground after you put in new fuse.

[dskall]

Re: Vizio E321VL dead blown fuse

A good visual of board for bad components. Follow traces down from fuse and test for shorted components.

[vinceroger69]

Re: Vizio E321VL dead blown fuse

check the bridge rectifier and any diodes/transistors on primary side too.

[ivtec]

Re: Vizio E321VL dead blown fuse

Thanks guys:i've checked some components and seem to be ok, but there are 4 Mosfets KF5N50, the 2 i circled in the pic check short,

[ivtec]

Re: Vizio E321VL dead blown fuse

Thanks guys:i've checked some components and seem to be ok, but there are 4 Mosfets KF5N50, the 2 i circled in the pic check short,

Hi guys any suggestion why these 2 mosfets test short in circuit??

[dick_barton]

Re: Vizio E321VL dead blown fuse

Without a schematic it not really possible to say. However you could use your meter and check all the components the copper tracks from the blown Mosfets lead to and test those devices.


What's the number on the part highlighted

[dskall]

Re: Vizio E321VL dead blown fuse

Remove mosfets and test them out of circuit

[ivtec]

Re: Vizio E321VL dead blown fuse

Without a schematic it not really possible to say. However you could use your meter and check all the components the copper tracks from the blown Mosfets lead to and test those devices.


What's the number on the part highlighted

Thanks dick_barton, that's a STR W6053N IC 150

[dick_barton]

Re: Vizio E321VL dead blown fuse

With the set powered off and plug removed from the mains set your meter to ohms and measure between:-

pins 1 and 3
Pins 1 and 5
Pins 3 and 5

for low resistance or short circuit.

[ivtec]

Re: Vizio E321VL dead blown fuse

With the set powered off and plug removed from the mains set your meter to ohms and measure between:-

pins 1 and 3
Pins 1 and 5
Pins 3 and 5

for low resistance or short circuit.

Thanks dick_barton;appreciate your time;

with power supply board out of the tv

pins 1 and 3=10.6 ohms
Pins 1 and 5=10.2 ohms
Pins 3 and 5=0.6 ohms

[dick_barton]

Re: Vizio E321VL dead blown fuse

You need to carefully unsolder it. The readings indicate the internal mosfet (or maybe some component in parallel with it) is shorted. Once removed you can repeat the test and if identical you need to order a replacement.

[ivtec]

Re: Vizio E321VL dead blown fuse

You need to carefully unsolder it. The readings indicate the internal mosfet (or maybe some component in parallel with it) is shorted. Once removed you can repeat the test and if identical you need to order a replacement.

Thanks i'll do that,i also just removed these 2 mosfets and they both are short out of the board

https://www.badcaps.net/forum/attach...1&d=1587353358

[dick_barton]

Re: Vizio E321VL dead blown fuse

Hi ,
If you could add your photo's as attachments to your replies it means that others who may have this problem at a later date will still have access to the photo's.

[petehall347]

Re: Vizio E321VL dead blown fuse

there will also likely be bad gate drive resistors to hunt down .

[dick_barton]

Re: Vizio E321VL dead blown fuse

+1
Yes, you should check all the components around the two mosfets that blew. Luckily enough it looks like the circuits for the other pair of mosfets are identical so you should be able to compare the readings when checking the components with your meter.

[budm]

Re: Vizio E321VL dead blown fuse

So the STR SMPS IC has Drain and GND resistance of 10 Ohms.\
Then you also have two shorted MOSFETs out of 4, those 4 MOSFETs are for the Inverter transformer drive circuits.
How about the PFC MOSFET mounted on the heatsink next to the red PFC inductor?
To have that many failures are really bad, I just hope that I can trust your DATA you are providing.

[ivtec]

Re: Vizio E321VL dead blown fuse

+1
Yes, you should check all the components around the two mosfets that blew. Luckily enough it looks like the circuits for the other pair of mosfets are identical so you should be able to compare the readings when checking the components with your meter.

The other 2 mosfets are good in circuit.


i just took out of the circuit STR W6053N and measured with ohms.

with positive prong on 1 and negative on 3= OL
+ ----------------------1 and negative on 5=OL
+ ----------------------3 and negative on 5=0.673 M

with Negative prong on 1 and positive on 3=336 Kl
- ---------------------- 1 + 5=0.71M
- ---------------------- 3 + 5=0.339KL

[ivtec]

Re: Vizio E321VL dead blown fuse

So the STR SMPS IC has Drain and GND resistance of 10 Ohms.\
Then you also have two shorted MOSFETs out of 4, those 4 MOSFETs are for the Inverter transformer drive circuits.
How about the PFC MOSFET mounted on the heatsink next to the red PFC inductor?
To have that many failures are really bad, I just hope that I can trust your DATA you are providing.

Thanks Budm; i just took out PFC MOSFET mounted on the heatsink next to the red PFC induct-or?and it's also bad, Q602 =KN060

there is also a kit for this power sup ,but i don't know if i trust this?

http://www.ebay.com/itm/Vizio-0500-0...3D272308911105



Also there is a power supp board on sale here,don't know if this is trustworthy!


http://www.buyqual.com/plhd-a943b-ep...1310-lips.html