Vizio VSA26LHDTV10T. Had power surge ....

[njgretz]

I'm looking for help on a Vizio VSA26LHDTV10T. Had power surge and now just the front light comes on nothing else. I did a quick test on the power board. On the printed board by the pins/ribbon cable on each side it says 24v on pins (each side). With the board plugged in, all 8 - 24v contacts measure 12.8v. I'm kinda new to this, any ideas on where or what to do next? Thank you for any help. None of the caps are visually bulging. The solder points on the underside of the board on the biggest cap look a little burnt. It's lifted off the 'glue'. The big transformer looks like it got heated up, like it leaked grease. If look at the pics, you can tell heat went through the board. Thanks much for any help

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Can I get the picture that show the whole board, top and bottom side?
Is it also Vizio VSA26LHDTV10T, not VA26LHDTV10T?
Vizio VSA26LHDTV10T nothing comes on this one.

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

It looks like this power supply ?
http://www.shopjimmy.com/vizio-adtv8...upply-unit.htm
If it is, then you need to find out if you do have >360VDC on the TWO LEGS of the main filter cap when PS-ON is present.

[njgretz]

Re: Vizio VA26LHDTV10T. Had power surge ....

Yes, you are correct I typo'd.

Thank you for catching that.
I put the ground on the heatsink and red probe on each of the big (laying down) caps legs. 62.8v on each leg.
I misspoke in my initial message. On the pinsets there are two 12v pins and six 24v. all read 24v pins measure 12.8v. and the two 12v pin are 0.
Thanks for any help!

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Post 3 "you need to find out if you do have >360VDC on the TWO LEGS of the main filter cap"
Probe on each leg of the cap, you cannot use chassis or heatsink as the GND for your meter, you are working in the PRIMARY side of the circuit.

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

My apologies, won't happen again.

Meter reads 170volts with probe on each leg of biggest capacitor.
May I ask how you knew to look for 360v>?
Is this a consistent number I could look for in the future on other TV's?
I couldn't find a schematic for this TV.

Thanks much

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

This power supply board has PFC Voltage booster circuit that is turned on when PS-ON is present which then the circuit will boost the DCV on the main cap from 170VDC to >360VDC.
So you need to troubleshoot the PFC Voltage booster next.

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

I am new to this and am not sure how. Could you please elaborate? I can't find a schematic for my board so I don't know what voltages to look for. Hell I don't know where to put the ground test probe if I were to test it now that I think about it.

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

"May I ask how you knew to look for 360v>?
Is this a consistent number I could look for in the future on other TV's?" If it has PFC Voltage booster, you can tell by looking at the board.
"I am new to this and am not sure how. Could you please elaborate?"
Well, look up PFC Voltage booster for TV:
https://cdn.badcaps-static.com/pdfs/...d13ffed70f.pdf

https://cdn.badcaps-static.com/pdfs/...f33e6f6571.pdf

I still need the WHOLE picture of the bottom side of the board to locate the PFC Controller IC so you can get the P/N for the IC to locate and test the VCC pin of the PFC Controller IC, or buy a new power supply board since are going to be dealing with SMD soldering and de-soldering.
Not only that the power supply is damaged, you may find out later after getting the power supply working first just to find out that the main board and other board may also be damaged.
You are not going to find the diagram for this power supply board unless you are willing to spend days tracing out the board.

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Here are some more pics of the bottom of the board. Let me know if they are not good enough.

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

https://www.badcaps.net/forum/attach...6&d=1425256403

OK, the 8-pin SMD IC 909? (cannot clearly the number) should be the PFC IC. The 7-Pin IC901 is the SMPS IC.
So get the P/N of that PFC IC.
Check PFC diode D904 also.

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

There are two 8 pin.
The one on the backside of the board by the cables (opposite the power cord input) says:
5430
TI 95H
ZKW9G4

The 2nd one, (VERY HARD TO READ)
SG6961SZ
B1AM5063925Y

7 pin says
P1337

PFC Diode
STTH5L06FP
GK03B VU
CHN 918

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Well I found the culprit on the back lite inverter board. Please see attached photos.
Just need some quick info. How would you guys (the pros) go about it?

I was just going to order a new transistor, try to clean up the crap burnt on the connection and hope it works. However I did test continuity with the transistor off the board and it was good.

Any thoughts or ideas? How would you clean the burnt stuff off?
Would you buy a new transistor?
Thanks for any input

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Burnt out power MOSFET like that should have blown the fuse on the inverter board also.
And you do not have the cables from the power supply board to the inverter board connected, do you get >360VDC on the filter cap?
Also show the picture of the whole inverter board.
It looks like this one:
http://www.shopjimmy.com/cmo-vit7006...t-inverter.htm

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Sorry cables were not connected, I pulled the board out to work on it.
384VDC on main filter cap.
Pictures are attached

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Sorry cables were not connected, I pulled the board out to work on it.
384VDC on main filter cap.
Pictures are attached

OK, so now you do have >360VDC which I thought you have indicated that it stays at 160VDC.
So fuse F2 on the inverter board is OK?

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

I didn't have the board powered at first (I was totally green).
I've read a ton of articles since and have a better handle now.
You were right the fuse is dead.

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Please read 1st response, I noticed something else but I don't want you to miss my last reply.

Please take a look at these pictures. All but 2 of the 'transformers' solder connections the 2 prongs are separated. As you can see 2 of them are now soldered into one connection. I noticed it because one of the transformers looks like it was turned 5deg.

Should I unsolder and re-solder with prongs separate right?

[budm]

Re: Vizio VSA26LHDTV10T. Had power surge ....

pin 2 and pin 4 are tied together by that big copper pad so that solder bridge on pin 2 and 4 do not matter.

[njgretz]

Re: Vizio VSA26LHDTV10T. Had power surge ....

Well I finally got a new transistor and fuse in the mail. Only fuses I could order were 6.3a 160v. Original fuse was 7.0a 160v. I plugged in the tv, front light came on right away same as before. I turned the power on, front light changed colors, same as before.
Still no picture, no backlight, no sound, nothing. Fuse is dead again. Power board is good, 24v at all connections. Something on the inverter board has to be spiking/blowing the fuse. Any ideas on where to look next?