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-   -   Vizio VO42L Issues: Need Guidance (https://www.badcaps.net/forum/showthread.php?t=96515)

ChillingCicada 06-09-2021 05:47 PM

Vizio VO42L Issues: Need Guidance
 
We've had our Vizio VO42L since before 2010, and it's worked flawlessly this entire time. However, just recently it started emitting a high-pitched buzzing/humming sound. I followed the basic troubleshooting tips of just unplugging it for a moment, and even holding down the power button while doing so, all to no avail.

Furthermore, after I attempted these basic steps and powered the TV back on it would always begin visually flickering while the sound stuttered. After a few moments of being turned on this would go away, but it still periodically comes back.

I also disconnected every device from the TV, but it didn't have any apparent affect upon the problem whatsoever.

I've just ordered a new power cord, because Vizio claims this could be the problem, but I obviously have my doubts as to whether or not this will solve the issue at hand.

Meanwhile, I've also taken the back off of the TV after unplugging it, and currently have it set aside for further troubleshooting. My biggest question at the moment is what the most likely culprit is, and/or is there anything else I can do right now in order to isolate the issue here?

I've taken photos of the main board and power board, which I've also noted the model numbers of, but I'm hoping that I can be guided in the proper direction before I potentially start ordering a bunch of unnecessary parts.

Thank you.

dick_barton 06-10-2021 06:39 AM

Re: Vizio VO42L Issues: Need Guidance
 
If you could post your photo's of the boards they may help.

ChillingCicada 06-10-2021 08:32 PM

Re: Vizio VO42L Issues: Need Guidance
 
7 Attachment(s)
I've attached some photos of the boards from a few different angles. The only backplate I haven't removed so far is the one covering the board on the far left-hand side of the TV. If anymore details are needed, just let me know. Thanks.

dick_barton 06-11-2021 06:09 AM

Re: Vizio VO42L Issues: Need Guidance
 
The power supply could do with a good dusting. I would check all the solder joints on the underside of the power supply especially around transformer joints. The coils at the output also may also have run hot so I would check the solder joints on them too.

ChillingCicada 06-11-2021 10:29 PM

Re: Vizio VO42L Issues: Need Guidance
 
1 Attachment(s)
I do admit that it had some dust, lol, although I was surprised at how little there was inside the set compared to some other devices I've opened up, especially at a decade plus in age.

I just gave it a dusting as you mentioned, and I took some photos of the underside. Everything looks okay to my eyes, but I'm including another photo so you can take a look.

I also have a video clip of the issue from just now, hopefully this will also prove useful:
https://drive.google.com/file/d/1Iui...ew?usp=sharing

dick_barton 06-12-2021 04:22 AM

Re: Vizio VO42L Issues: Need Guidance
 
J7 link doesn't look so good. Also D604 appears to have some residue around it.

dick_barton 06-12-2021 08:02 AM

Re: Vizio VO42L Issues: Need Guidance
 
It may well be worth reading the comments by Budm on the following page
https://www.badcaps.net/forum/showth...ight=dps-260hp

ChillingCicada 06-24-2021 10:03 PM

Re: Vizio VO42L Issues: Need Guidance
 
Quote:

Originally Posted by dick_barton (Post 1051990)
It may well be worth reading the comments by Budm on the following page
https://www.badcaps.net/forum/showth...ight=dps-260hp

I really appreciate the advice you've given me.

I ended up replacing the power board since I found a great deal on one, and so far the flickering is completely gone. There remains the slightest buzzing sound, along with some undulation in that sound, at least when I'm listening to the exposed board right there in front of me, but the sound appears to have lessened even more so as I've left the TV turned on for a few minutes. I've attached a video so you can double-check it for me before I reassemble the entire set and place it back on the stand.

I may just be somewhat jumpy of any sounds emanating from the boards given what just occurred, so I'd prefer a second set of ears letting me know if all sounds well.

Thanks.

https://drive.google.com/file/d/1zPc...ew?usp=sharing

dick_barton 06-25-2021 03:45 AM

Re: Vizio VO42L Issues: Need Guidance
 
If it is a used power supply then I would check the the underside of the board to ensure all the solder joints especially on the larger components are well soldered.

ChillingCicada 06-25-2021 04:41 AM

Re: Vizio VO42L Issues: Need Guidance
 
2 Attachment(s)
Quote:

Originally Posted by dick_barton (Post 1054864)
If it is a used power supply then I would check the the underside of the board to ensure all the solder joints especially on the larger components are well soldered.


Please let me know if anything stands out to you in the photo of the recent board which I've just installed. You have a far better eye for what does and does not look good, and I'll be certain to double-check anything that you recommend I do so here

Also, just for my own learning experience, what are some giveaways I should look for in regards to what constitutes a well-soldered joint? I know that no components should be loose, and I obviously expect a clean looking solder from the factory, but is there anything else in particular that I should keep an eye out for especially with regards to wear and tear?


Thanks again for your time.

Edited to add: I just noticed that the new board doesn't appear to include the plastic spacers. How critical are these to its proper operation?

dick_barton 06-25-2021 06:53 AM

Re: Vizio VO42L Issues: Need Guidance
 
The photo's are not sharp enough to make out any poor joints and shadows do not make it easy to tell. An example is D120 looks as though one pin is not fully soldered. However it could just be the shadow.

What you are looking for is that transformers, coild and mosfets solder joints look good.
Have a look online to see various examples
https://en.wikipedia.org/wiki/Soldering

ChillingCicada 06-25-2021 07:25 PM

Re: Vizio VO42L Issues: Need Guidance
 
1 Attachment(s)
Quote:

Originally Posted by dick_barton (Post 1054908)
The photo's are not sharp enough to make out any poor joints and shadows do not make it easy to tell. An example is D120 looks as though one pin is not fully soldered. However it could just be the shadow.

What you are looking for is that transformers, coild and mosfets solder joints look good.
Have a look online to see various examples
https://en.wikipedia.org/wiki/Soldering

After giving it a closer look, it appears that there is a solder issue with J48. Would this be causing any of the issues?

Also, is it normal for the power board to ever make any noise at all, or should it be completely silent? Additionally, is it also normal for the heatsink over the capacitors to get rather warm when powered on?

dick_barton 06-26-2021 03:03 AM

Re: Vizio VO42L Issues: Need Guidance
 
It's not a great solder joint but it does look as though it is connected to the pad. I would however resolder the joint.
Heatsinks over capacitors are a poor idea because I believe they lead to premature failure of the capacitors below the heatsink.
Unfortunately it does look as though some power supplies are noisy if you look at the amount of silicone type sealant they use on components.

mmartell 06-26-2021 08:32 AM

Re: Vizio VO42L Issues: Need Guidance
 
Quote:

Originally Posted by ChillingCicada (Post 1055046)
Also, is it normal for the power board to ever make any noise at all, or should it be completely silent?

Look up the theory on Switch Mode Power Supplies. These work on very high frequencies usually out of the audible range but like dick said they use silicon and such to keep the vibrations of those frequencies from lending sympathetic resonation into ranges that we do hear. Failing components and cracked solder joints can also have a hand in that especially on Transformers and coils.

So yes it's "normal" in that aging power supplies can become out of spec from design causing audible noise.

ChillingCicada 07-05-2021 02:02 AM

Re: Vizio VO42L Issues: Need Guidance
 
1 Attachment(s)
I really appreciate the help, advice, and reading material.

I replaced the power board, and I did so with one from a repair/replacement store online which includes a warranty.

The TV appears fine upon being powered up, but then when I have a signal finally coming over the HDMI cable it starts to stutter all over again. The biggest difference with the new power board is that all appears fine when the HDMI source is not plugged in, whereas before with the old power board it was flickering regardless.

Here's a video clip of the remaining ssue: https://drive.google.com/file/d/10U_...w?usp=drivesdk

Is this now a main board issue given that it only appears when something is transmitting a signal via HDMI? The alternate TV I've temporarily plugged in for testing purposes (A much smaller set which I've borrowed) seems to be doing fine with this HDMI cable and corresponding DVR.

Also, somewhat related, I'm now noticing this faint white wavy line or mark across the very top of the screen, almost like a sweat mark on a baseball cap. Any ideas what this could be as well?

It's such a bummer right now, because once I reassembled the TV and turned it on everything appeared to be working perfectly fine again, but the moment the HDMI signal began transmitting it was another headache all over again.:confused:

Edited to add: I've included a photo of the wavy line, and a video clip of the remaining HDMI stutter:

ChillingCicada 07-11-2021 06:29 AM

Re: Vizio VO42L Issues: Need Guidance
 
I'm currently looking at just replacing the main board, but the exact main board model number my TV currently has is more expensive and less available than the other main board model number for the same TV model.

Current main board model: https://www.shopjimmy.com/vizio-3642...w-571374034616

Other main board model: https://www.shopjimmy.com/vizio-3642...vo42lfhdtv10a/

Is there really such a difference between these two items whereby the other model number truly wouldn't work in my TV set?

dick_barton 07-11-2021 10:22 AM

Re: Vizio VO42L Issues: Need Guidance
 
If the wavy line is constant and doesn't move I wonder if it's something to do with the panel diffuser screens.

What's the picture like using other inputs or off-air. Does it suffer the same flickering.


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