VO47L FHDTV10A no picture on 2 of these sets

[djrobbaron]

Hello folks. First time poster, 8 month lurker. Be gentle

I have two Vizio 47" TVs, model VO47L FHDTV10A. I believe budm asked for confirmation on another thread concerning the second digit. It is indeed the letter O and not the number 0.

Both of these sets have the same boards. They both have the same symptoms. Plugs in to standby (amber logo comes on). Powers on with button (logo changes to white. I don't have remotes for either) The screen does not power on.
I have checked a few voltages against chassis ground per this YouTube video from one of your members I subscribed to a while back. Unfortunately I don't remember his username here. http://www.youtube.com/watch?v=jR2UZhoDC2c

I've been clumsy at best at getting these voltages and the video goes too fast to follow with my beginner's multi-meter prodding. I'd LOVE to have a list of points to check and their proper values.
All the can style caps appear to be in good condition on both the power supplies and the main boards.
Confession: I picked these sets up over a year ago and ordered a couple refurb'ed power supplies from shopJimmy I believe. My tinkering attempts were interrupted until now and I honestly don't remember if the boards I'm using now were the originals or the replacements. The replacements were NOT in beautiful condition either and I was suspect of their worth, but I do have them and they also share the same part numbers. My intentions, in true badcap forum style, is to repair originals and refurbs and to sell the ones I don't use.
The Master & Slave inverter boards for both have bad caps and burnt traces on their ICs. I replaced the caps on one set before my several month break. Actually, during the cap replacement was when I discovered the burnt IC traces which was the first part of me getting overwhelmed and dropping the project for too long.
I remember hearing unhealthy noises from all the power supply boards I tried. I don't know if it's their fault or a result of something down the line.
The service manual I was able to find had the good sections omitted.

I'm deferring to you guys on more of this stuff than I'd like. I hate entering this feeling so mentally naked. I think I'm a quick learner and I respect you guys and your time. I will do everything in my power not to waste either. I have thick skin, so be blunt if necessary at any time to help un-noob me bit by bit. I have tried to find more information on my own to no avail. I have several other TVs, PC parts, and pro audio equip that I'll be progressing on to after this. I also intend to become a veteran and share the burden/pleasure of helping folks just like me as I'm able. All help is appreciated. Thanks in advance.

I'm including several pics to hopefully express anything I don't know how to yet.

Label (in case there's info here that changes with revisions I'm not aware of)


Master Inverter Board (showing damaged caps and burnt IC traces)


Nasty burnt area of PCB on the top left corner of the Power Supply (Should I say PSU from here out?) that is beneath cap CY5 (determined from looking at one of the other power supplies).


The flip side of the above power supply damaged area. (again that cap was once visibly labeled Cy5)


Overall layout of these sets with no boards pulled.


That completes my first cry for help. I hope it's formatted the way you guys prefer. All set to provide any additional info

[johnboy1313]

Re: VO47L FHDTV10A no picture on 2 of these sets

Follow these steps to check the voltage regulators on the mainboard. Also check any surface mount fuses that you see while you're there.

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

Thanks for the quick reply johnboy1313. Your post didn't show the steps for me to follow to check the voltage regulators. I have picked a set to start with and have checked all surface mount fuses I saw on the main board (2 surface mounts), power supply(1 ceramic on input side), and inverters(1 surface mount on input side of each). By checking, I mean I set my multimeter to continuity and put the leads on either end of the fuses in circuit and confirmed continuity with audible tone. If that is the procedure, they all checked out.

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

While I was waiting I recalled seeing something similar in some of your posts I read long ago mentioning checking voltage regulators. This made me wonder if "follow these steps" was a typo or was missing the link. I found one of these prior posts with the link
https://www.badcaps.net/forum/showth...999#post300999
you shared of retiredcaps instructions.

I'll head that route in case that's what is coming next.

(see, I'm not gonna be one of those lazy posters )

I'll additionally look up the posting method to linking with text instead of the url, that slipped from a wrinkle at some point.

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

While I'm in that process, is it probable that the IC's with the burnt traces on the inverter boards will need to be replaced or do you think soldering the traces back will suffice? From the best I can tell due to the burnt "divot" on the 5th digit, they are this part. (see the condition of the ICs in the second photo of the original post)

[philliesfan30m]

Re: VO47L FHDTV10A no picture on 2 of these sets

could you post pics through here not another site?

[newtothis]

Re: VO47L FHDTV10A no picture on 2 of these sets

Those pics are not good enough to help, try a higher resolution so we can see clearly.

not trying to be picky but without us being able to see what we are dealing with it will be very hard to help

[mu2]

Re: VO47L FHDTV10A no picture on 2 of these sets

Hi,

I looked through my notes on a repair that I did on this same model.
There is a cap that fails on the power supply board - in the corner as I recall.
Value is 470 mf 35 volt - it was visibly puffed. I also replaced the caps on both inverter boards - 680 mf 35 volts and a 10 amp smd fuse on one inverter board.
That high voltage cap needs to be replaced as well.
Good luck.

Mike

[mu2]

Re: VO47L FHDTV10A no picture on 2 of these sets

Sorry, I jumped the gun and posted without fully reading you original post.
Looks like the parts I mentioned have already been replaced.

Mike

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

Holy cow. I didn't realize the thumbnails weren't expanding. Fixed below. Thanks for the heads up.

Label (in case there's info here that changes with revisions I'm not aware of)


Master Inverter Board (showing damaged caps and burnt IC traces)


Nasty burnt area of PCB on the top left corner of the Power Supply (Should I say PSU from here out?) that is beneath cap CY5 (determined from looking at one of the other power supplies).


The flip side of the above power supply damaged area. (again that cap was once visibly labeled Cy5)


Overall layout of these sets with no boards pulled.

[philliesfan30m]

Re: VO47L FHDTV10A no picture on 2 of these sets

what did you replace so far?

[budm]

Re: VO47L FHDTV10A no picture on 2 of these sets

That blue CY cap is the safety cap between Line and Chassis ground, the TV must have been hit with big surge. The cap is not needed for the circuit to function, it is for reduce the noise in the AC power line. You may have lots of damages in this TV due to surge. Components on the power supply boards will have to be closely checked out for damages.
The inverter board will need to be repair or replace, the main board and the T-CON boards will have to be checked. So you can have lots of problems.

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

Ok, catching up here. First things first I guess, the voltage regulators on the main board starting with the one closest to the power plug and progressing away. I believe I got them all, there are a few components on the board that look similar, but their ID's aren't even close to the ID's on the ones below. A couple of these measurements would alternate by 1 digit, I've included the higher value in parentheses. I have no idea if such fluctuation is important, but figured I'd better mention it. Maybe it's my cheap DMM, maybe it's relevant to the problem.

U2
AMC1117
F0748M
Pin 1 = 2.02
Pin 2 = 3.26 (3.27)
Pin 3 = 5.07

U8
AMC1117
F0748M
Pin 1 = 2.0
Pin 2 = 3.24 (3.25)
Pin 3 = 5.11

U33
AMC1117
F0748M
Pin 1 = 2.04
Pin 2 = 3.303
Pin 3 = 5.06 (5.07)

U7
AMC1117
F0748M
Pin 1 = 1.02
Pin 2 = 1.26
Pin 3 = 3.3

U9
K1117 515
F0748M
Pin 1 = 0
Pin 2 = 1.50 (1.51)
Pin 3 = 3.3

@mu2, or Mike, and budm: I have decided to go with a different power supply than the one with damage under the blue cap @ CY5 for the first TV (the one referenced in the above photo). Mike, interestingly enough, the one pictured has a vacant spot where the "corner cap" C241 470uf 35V should be. Not sure if that was me months ago when I first tackled this or not. Likely so, because I ordered a few Panasonic caps with that value to replace some Nichicon's on the power supplies. I'll tackle that power supply with the 2nd TV

The power supply I decided to go with has the C241 replaced. The area above it shows some charring on the top side of the PCB around L240A & L240B (springy copper looking things) and R241A, R241B, R241C, R241D $9 (staple looking things). All solder points and traces on the bottom side of that area are intact so I don't think it's a problem. I'm guessing it was from the failing C241 that was replaced. The power supply I decided to wait on with the absent C241 shows no charring there. I guess that one was caught before the cap completely failed.

Since work has obviously done to all 4 power supplies I have, I am left to assume that these TV's were refurb's. Oh well, pressing on...

@Mike: Yes, I have already replaced the original 680uf 35V Samwha caps on the inverters for this set with this part. Did the IC's between those caps on your repair have a burnt trace like mine (see earlier pic)? If so, did you have to replace that or was it as simple as resoldering the burnt trace? The only fuse I see on the inverters is a 12A 65V fuse at F1. I've checked those on all the inverters for continuity and they all gave a tone. I figure that's the fuse you meant, but if there is another that I'm not seeing, I'll need a little help identifying it.

@philliesfan30m: I have replaced the caps on the inverters and the cap at C241 on the power supply I'm going with has been replaced. During my work thus far, I managed to lose one of the screws that attaches the power supply to the standoffs on the chassis. How important are those? >.<

I'm including a photo below to show the charred area above C241 referenced above. I believe I've gotten picture posting correct for this forum finally

[mu2]

Re: VO47L FHDTV10A no picture on 2 of these sets

I'm guessing the chip on the inverter board is a BD9897FS. That is a common failure and if there is a burned mark most likely the chip is bad. Search for other posts on this ic and you'll see that there is a method to check the resistance of certain pins to determine if it's bad. I see that there are kits available on Ebay that include the chip as well as the four mosfets. These could also be bad. If you plan to replace the chips consider getting some chipquik - it's a low melting point solder that really works well for removing surface mount components. You might also want to check other posts because there is a factory modification on some of the inverter boards - not sure if your boards are the ones. The fuse you mentioned is the one I referred to in a previous post.
Also, looks like U-7 could be bad on your main board. There isn't a 1.25 difference between pins 1 and 2.

Mike

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

Thanks Mike. The chip on the inverter boards is indeed the BD9897FS. I'm pouring through the references in the forum now and then it's back to the voltage regulators. Does it look like I got all of them? I may borrow a working one from the other TV to test since they each have 4 of the same one.

[mu2]

Re: VO47L FHDTV10A no picture on 2 of these sets

I would recheck the voltage on pin 2 of U-7 and make sure it isn't 2.25 instead of what you reported. The 1117 voltage regulators come in several flavors - some have a fixed voltage output and some are adjustable. If you have the part number correct on U-7 it looks like it's the adjustable version where the output voltage is selected by a resistor network on pins 1 and 2. I suppose that there could be something dragging the voltage down on the output side of the regulator giving you a low voltage - not sure what happens with these regulators in that case - they may just shut down internally.
One of the other 1117 regulators you show has a 515 in the part number - most likely a fixed regulator at 1.5 volts which is what you measured.
Based on the history of this part failing in various models of Vizio sets - I wouldn't even think twice about replacing it. The cost of the part is low and you would be sure that the new part isn't defective. Digikey has them.
I don't have one of these power boards on hand to tell you if you found all the 1117 regulators.
You might want to look into a set of inverter boards for the tv. I've seen board sets - master and slave listed that are newer revisions. Make sure you check the inverter ic's and fets on both the master and slave boards.

Mike

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

Mike, I did screw up on U7 there was no 1 on pin 1. In other words:

U7
AMC1117
F0748M
Pin 1 = .02
Pin 2 = 1.26
Pin 3 = 3.3

I sincerely apologize for the error transcribing my notes to screen.

[mu2]

Re: VO47L FHDTV10A no picture on 2 of these sets

Voltage looks good to me. No point in replacing it.

Mike

[budm]

Re: VO47L FHDTV10A no picture on 2 of these sets

Sorry, wrong post.

[djrobbaron]

Re: VO47L FHDTV10A no picture on 2 of these sets

I've ordered the BD9897FS chips for the inverters and also ordered enough mosfets to replace all of them. I also put the chipquik on there.. however I just realized I probably ordered the wrong thing. I had drag soldering on the brain and ordered this. On the plus side, I am pretty comfortable with my Hakko soldering station. I should be able to find the lowest workable temp. on a less sensitive part. I'm also using 63/37 so I can slap it on at an even lower temp. I'll let you know how the tack flux works in case you want to add it to your arsenal.