Vizio VO47L FHDTV10A No display

[Beowulf]

Re: Vizio VO47L FHDTV10A No display

Oh great, that helps a lot.

[Mayank]

Re: Vizio VO47L FHDTV10A No display

Hi:

Just wanted to thank everyone on this post. My Vizio VO47LFHDTV10A started "smoking" a few days ago. Luckily I was able to quickly switch it off and pull the power cable.

On removing the back cover, I found the 470uF/35V capacitor on the PSU board had been spouting smelly black electrolyte on the heat sink. The 4 nearby 1000uf/35V capacitors on the PSU board tested dead short. The 4 680uF/35V capacitors on the Master & Slave invester board were bloated and also leaking electrolyte. All the PCB fuses tested OK.

I replaced the 470uF/35V capacitor on the PSU board and the 4 680uF/35V capacitors on the two inverter boards with Low ESR Panasonic FR series capacitors from Mouser. The 4 1000uF/35V capacitors now tested OK.

The TV is alive - bringing much missed entertainment in our living room!

Thanks again guys!

Rgds
Mayank

[Robertknight]

Re: Vizio VO47L FHDTV10A No display

Im having a problem with the same model television. The caps on the master inverter board were bulged and the tv has no picture (or sound as far as I can tell). I get the typical orange on standby and white on power up on the logo. I replaced the bad caps for matching units, soldered in an external fuse to replace the damaged one on the inverter board. The problem Im having now is Im no receiving 24 volts from anywhere in the system. I pulled the board off the frame, hotwired in a ground pigtail and re-read the voltages, and Ive traced the line that provides the 24v power back to the top transformer-looking block circled in the first picture.
#note- I apoligize for not knowing the actual name of the part, but Im new to doing these repairs on anything more than replacing obviously bad capacitors.
So, I purchased a used PSU from Ebay, thinking that component had gone bad, but the replacement is giving me the exact same condition, and Im wondering now if there is some sort of switching involved and that power converter module is just not getting energized somehow. I am not getting 24 volts to any of the pins, and that unit is getting 65 volts input, and nothing on the secondary side. Im at a loss now, as I dont know if im looking at 2 bad pieces, or if theres another control problem thats keeping the 24v power from turning on.
BTW, theres a very thorough voltage video guide for this TV on Youtube that I used to cross reference the voltages, and everything seems to check out except the 24v.

[budm]

Re: Vizio VO47L FHDTV10A No display

Disconnect the cables to the inverter boards and see if the 24V will be present.
There is a signal called PS_ON (look for this pin on the power supply connector) which is from the main board and feed to the power supply board, when TV is turned on it should show >2.5VDC. This PS_ON will turn on the PFC Voltage booster which will make the DC Voltage at the TWO PINS OF THE MAIN FILTER CAP go from 165VDC to >360VDC, this PS_ON signal is also used to turn on the 12V/24V switched power supply.

[Robertknight]

Re: Vizio VO47L FHDTV10A No display

No 24v on the terminals with the cables unplugged.
Im getting around 3 volts at the power supply from the PSON terminal on the cable from the main board
Where can i find the main filter capacitor, or is that the part I highlighted?
*again, sorry for my lack of knowledge on the electronic parts
Thanks for the response btw.

[budm]

Re: Vizio VO47L FHDTV10A No display

The main filter cap is the biggest cap 450VDC rating laying on its side under the heatsink, you must be real careful because you are working on the hot deadly side of the circuit.

[Robertknight]

Re: Vizio VO47L FHDTV10A No display

On the big capacitor I'm getting about 160vdc when I turn the tv on, then off then read the voltage, but it drops off as im reading it. With the TV on Im getting a solid 338vdc input to it (I assume its the input side). On the output side, on or off I get 64VAC. BTW, again, Im using an electricians meter, so voltage might be +/- a bit.

[budm]

Re: Vizio VO47L FHDTV10A No display

OK, test the Voltage right at the two legs of the cap, when TV off it should be around 160VDC, when power switch is activated it should then jumps up >360VDC and stays there until the power switch is turned off.
You are working in the primary side so do not use the chassis or safety ground for the black probe of the meter, the negative leg is the GND ref. point for primary circuit ground point.

[Robertknight]

Re: Vizio VO47L FHDTV10A No display

Ok, I retested the capacitor using the metal shroud as a ground (couldnt find a 'reference ground') and it gave me more stable readings. The primary side went from 165 with the tv off to 395 with it turned on, but the secondary side was zero volts on or off. Bad Cap?
Just as a side note, if I take voltage from the metal shroud to chassis ground I get 65vac. is that normal for the framework to be energized?

[Robertknight]

Re: Vizio VO47L FHDTV10A No display

OK, so I replaced the 450V capacitor just to be sure and Im still getting the same voltage readings, 165 off and 390-ish on on the positive side and 0/0 on the negative side. Im guessing that either Im reading the voltage wrong or theres something else wrong with the system.
Can anyone help me with the 'reference ground' on this PSU btw, so I know Im at least reading the voltages correctly.

[cliff_hootarski]

Re: Vizio VO47L FHDTV10A No display

On the power supply, there is a "primary" and "secondary" side. It is delineated by a solid or dashed line(picture of power supply in post#43). On the "primary" side (the part of the power supply that is connected to house current)(read deadly), ground point(negative lead of you meter) will be the (-) side of the main filter capacitor, which is under the heat sink on the left, middle part of the picture. All DC voltage measurements on the "primary" side will be in respect to this ground point.

The ground point for the "secondary" side (right of the solid line which roughly divides the power supply in two) of the power supply is anywhere on the chassis of the TV.

[budm]

Re: Vizio VO47L FHDTV10A No display

OK, since you do have 395VDC right at the two legs of the main filter cap, then the PS_ON signal is OK because it activated the PFC Voltage booster circuit to boost the DC Voltage on the main cap from 160VDC to 395VDC.
So right now you will need to troubleshoot down to component level of the 12v/24v SMPS section next.

[mparker]

Re: Vizio VO47L FHDTV10A No display

This is an old thread but it helped me fix a 2009 VO47L TV that my neighbor put on the curb before moving. I followed the advice at the beginning of this thread and found bad capacitors on the Slave and Master boards as well as a bad fuse on the master board. I literally taped a 15A automotive fuse across the bad fuse then powered on the TV and it worked. Now I will be ordering the roughly $6.00 in parts to repair the TV the right way.
Just wanted to say thank you to the forum members who listed all this advice out here.

[jarred]

Re: Vizio VO47L FHDTV10A No display

Hello,
Problem details: TV turns on normally and lights up the vizio LED logo on the front but it doesn't show any signs of video. I tried connecting a video source (PS3, xbox etc) and play something to see If I could hear sound. I was not able to get any sound, although is unsure how I could perform the sound test accurately when I dont know what input the tv is currently set to. I did tried messing with the input button and also conecting the video source to all the inputs....










Anyway here is what I've found so far:

-On the inverter boards both caps, as circled in red, on each of the boards were bulged and I replaced them. I did a quick check on the transistors and they seem fine.

-On the Power supply board I found a bulged cap, as circled in red, and replaced it. The two inductors next to it are in bad shape leaving a very dark spot on the pcb. From the bottom there is delamination and some part of the board is lifted but the traces dont look bad. Anyway the PSU is providind all the output voltages as indicated on the output pins marked on the PCB.

This is as far as I'm able to get. Could this be inverters problems and how can I check?

Thanks

I have the same TV that won't turn on and am just beginning TV repair. This TV for the last six months has worked fine other than it started " snapping" real loud when it was turned off. I'm trying to find a schematic and start troubleshooting it, and any help would be greatly appreciated. Thanks

[RCA2000]

Re: Vizio VO47L FHDTV10A No display

I also had a VO47L set...with the "no raster" but power..problem. It was a freebie from CL. I grabbed it figuring it might be saveable...and if not...I would part it and sell the boards and stand.

I comfirned the problem...checked my PSU voltages...i run mode...all looked ok.. The sinks on the cold side of the PSU did not seem to warm up much...but I figured that was because there was no BL. So...I turned my attention to the BL inverter. this set has a pair of them ..a "master and a "slave inverter. After removing the shield form the master inverter...I checked my B+ on the fuse. As I suspected..it ws ok on the INPUT side and absent on the other side. I suspected one or more shorted MOSFETS...but found none. then I saw the caps.."puffed". so...with nothing to lose...I tacked on a couple on hand and a pigtail fuse.. It DID work !!! I was SURPRISED..since a blown inverter fuse usually means one or mre shorted MOSFETS or chips, dependng on what drives the inverter transformers. But not on THIS one. I then acquired the RIGHT physical type of SMD fuse and caps which fit under the shield.. replaced the caps o BOTH inverters.. (locally...from the ONLY electronics parts dealer in the Cincy area left..St. Clair electronics..) all is GOOD NOW !! This tv has a GREAT Picture too !!

[Shane711]

Re: Vizio VO47L FHDTV10A No display

Well I am not so lucky as everyone else. I had this TV for some time and it is not fixed yet. I repaired the power board and the inverters but still no picture. All my fuses are good and all my caps I upgraded to a slightly higher voltage. No shorts on the inverter boards and all my voltages seem to be good. The only thing I can think is maybe a bad IC on one of the inverter boards or something wrong with the backlights. Well I just checked the 2 ICs with my meter and found the IC on the Slave inverter to have a short. (Pins 1 & 11 are ground) After looking at it under my magnifier I found there to be a bubble on the IC, it is bad. I got 50PCS of those ICs (BD9897FS) coming so I will change it out and see what happens.