Vizio E601i-A3 Blown fuse on powerboard

[bkdadto3]

I can not see any obvious signs of a failed component, sticker on the board is
V09-60CAP000-00 F0020AA0B6WT 1260

I am just getting into this new hobby of repairing tv's, so please forgive my ignorance. I inspected the card and can see no physical damage, discoloration, or signs of being stressed. I replaced the fuse and it immediately opened. I am not inclined to replace any more fuses without identifying the root cause, but must admit I am stumped.

I purchased an ESR meter and the big caps look good as well as the yellow blocks look good on the card. I do have question about a cap across the AC input lines, it is currently reading 222.6nF out of circuit with a Klein Tools MM600 capacitor setting. The ESR value is 7.06 ohms, which the meter reports as being good if the value is less than 10uF. the writing on the cap is:

SCC. 22K275V-X2
MPXGMF40/100/21
250V-E-G

According to a data sheet I found:

Interference Suppression Capacitor:
Class X2(Safety approved)

Capacitance Range:0.0047uf~1.0uf

Rated Voltage:
50~60Hz
310VAC: UL ; cUL
275VAC:VDE/ENEC ; CQC

I would like to solve this as it should be obvious usually wherever the smoke was let out, the electrons follow. No signs of smoke exiting and that is a bit frustrating. Any guidance would be appreciated. Should I be looking elsewhere as well?

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

No need to waste time on that X cap. That cap is not needed for the circuit to function.
You will get more uploading good clear straight shot pictures of the whole top and bottom side of the power supply board and also pictures of the whole backside of the TV showing all the boards.
Do not put any more fuses until you find the shorted circuit otherwise you will cause more damage to the board.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

Here you go. I thought I had attached them, but obviously not.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

By the way, the discoloration around the leads for the rectifier were done by me. I took it out and tested it and it was fine.

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

Check the RESISTANCE between the two outter pins of the Bridge, and then between the two inner pins of the bridge, report what resistance you get, make sure to report if it is in Ohm, K Ohm, or M Ohm.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

I am posting pictures as they speak better than words.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

Remember, out of circuit, the rectifier tests correct accoirding to the datasheet.

[jetadm123]

Re: Vizio E601i-A3 Blown fuse on powerboard

The outer pins represent the output of the bridge rectifier. Since you're saying it's good and your meter shows .3 ohms, then that should tell you that there's a short somewhere beyond that bridge. Try checking some of the components connected to the "+" pin of the bridge for a short.

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

I am posting pictures as they speak better than words.

That is why I have you check the outer pins and the inner pins, sure enough, you do have shorted circuit due to shorted load..

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

I cannot really tell from the pictures if those two snubber caps are burnt or not but they look like they have top section burn mark.
Check the resistance of those two caps.
I can also be shorted MOSFET which are mounted on the heatsink next to the cap that you also need to test the resistance between S and D pins.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

The cap measures good with the esr meter. There is a grey colored adhesive applied to the cap, I am assuming to support it. The reading between the S and D pins is a dead short.

[vinceroger69]

Re: Vizio E601i-A3 Blown fuse on powerboard

i would remove the mosfet and re test it out of circuit

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

That is the MOSFET for the PFC Voltage booster circuit, if the MOSFET tested shorted off the board then I would replace the PFC Controller at the same time too.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

it was a FDPF 16N50

I have one on order, please elaborate on other components to check, I am new to this and am not sure what specifically you are referring to when you say PFC controller. Is this a single component or a configuration of components?

[vinceroger69]

Re: Vizio E601i-A3 Blown fuse on powerboard

on the underside of the power supply on the hot side of the psu there are some black ics soldered to the psu can you read the part umber on them?

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

U101

PCRDJ
FAN
7930C


Look correct?

[vinceroger69]

Re: Vizio E601i-A3 Blown fuse on powerboard

U101

PCRDJ
FAN
7930C


Look correct?

yes im sure thats the ic thats advisable to change at the same time im sure budm will confirm its the pfc ic

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

FAN7930C spec sheet. Replace the IC at the same time otherwise youi can take a chance of blowing the new MOSFET if the IC is damaged when the MOSFET shorted out.
You will have to verify that any component between the Gate drive output pin of the IC and the Gate pin of the MOSFET are not damaged.
Also need to verify if the Resistor (usually less than 1 Ohm) between Source pin and the hot side circuit GDN is still good or not.

[bkdadto3]

Re: Vizio E601i-A3 Blown fuse on powerboard

Well, I got lucky. I replaced the MOSFET and it has been running for about an hour now with no issues. Thanks all for the help.

[budm]

Re: Vizio E601i-A3 Blown fuse on powerboard

Thanks for the follow-up, you are very lucky indeed.