How to Fix your Vizio M470NV and M550NV

[bpcannan]

Re: How to Fix your Vizio M470NV and M550NV

I just joined yesterday - and after some weeks of frustration browsing about I stumbled in here searching for clues to fix the sound on my 12 year old Vizio M550NV which I still use in the 'man-cave' and am trying to avoid buying a new one for it. I replaced the t-con board 4 years ago and all has been well but for the $190 for a new main board (the cost of a Insignia 50 inch TV) I thought I'd give it one more shot.

Saw #5 below and that was my issue and pretty much knew the 'correct way' was not going to happen so I waved a heat gun over the back of the main board chip for a few minutes then walked away for a hour or so to let things cool. popped the board back in - and wow - sound! Sure maybe I'll have to do it again in 6-11 months andmaybe it won't work that time and I'll have to spring a for another TV. But dang, I do like the picture on this one - and my original VIZIO 42GVL is still working fine too - bought it in 2006.

Great contribution Nick.
PS -and no way was my wife going to let me bake this in her oven!

Brian

+++++++++++++++++++++++

Hello everyone, my name is Nick, and I am the owner of Nick's TV repair. I am going to go over how to diagnose and fix your Vizio M470NV and M550NV TVs.

This thread should take care of 99% of all failures we see with these two models.

Experience:
We have helped fixed over 100 of these TVs in the past 6 months alone through our local and online repair services we offer on these models with a 97% success rate.

I will start by going over the extremely rare failures of this set first:

We have seen one M550NV experience a panel failure. The symptoms of a bad panel are going to be no picture on screen. We were able to diagnose this set by disconnecting one of the two ribbons between the T-con board and the panel. We disconnected one of the ribbons and turned the TV on, what we saw was a white screen on the disconnected side and a fully black screen on the other. We reconnected the ribbon and disconnected the other side. From there the disconnected side went from black to white, and the connected side was showing us proper picture. This meant that the side disconnected at the time was our faulty half which caused neither side to display on screen.

We have never seen in our shop these sets with bad LED's, bad LED driver board, bad power supply board, or a bad T-con board. However it is not impossible as there is a thread on bad caps with a one of these sets experiencing bad LEDs. It is extremely rare but can happen.

Now to the 99% of failures we see with these models are going to be main board failures listed below

Symptoms of a bad main board:

1. TV turns on, but the on screen vizio logo freezes and the tv eventually cycles off and back on again. (this can sometimes happen endlessly or until power plug is removed)
2. TV turns on, both sound and picture come through, however the TV menu is very slow to navigate and seems to freeze a lot.
3. TV turns on, the menus and component/coaxial input work, however the HDMI ports don't appear as optional inputs
4. TV turns on, menus work smart apps work, but the HDMI ports have no sound and no picture. (No signal keeps appearing)
5. TV turns on and HDMI ports work, but no sound
6. TV does not turn on, and the small vizio logo at the bottom of the frame keeps flashing white to orange endlessly
7. Tv does not seem to turn on, the vizio logo on frame does not flash but stays orange.
8. Tv logo goes from orange to white but the TV does not turn on.

Our first symptom is usually due to both a faulty Silicon Image chip with location number U41 and additionally a faulty transistor at location Q29. U41 is the larger IC close the the bottom HDMI ports and Ethernet port. You can check the chip by looking at the capacitors near/around it for shorts. If you find shorted capacitors, it is due to this chip malfunctioning. The Q29 transistor is located about 2 millimeters off to the right of the large heatsink. It is a very small three legged surface mount component. While in circuit, it should show around 10k ohm and slowly rising with the negative lead on the bottom leg and positive lead on the top left leg. With the negative lead still on the bottom leg and the positive lead on the top right leg you should be seeing around 29k-32k ohms. If you do have a shorted silicon image chip U41 but still good readings on your Q29 surface mount transistor, we still would advise replacing that transistor as well since hey tend to fail together.

Our second and third symptoms are due to a faulty Nand chip with location number U6. This will be the rectangular chip located under the heat sink. BE VERY CAREFUL WHEN REMOVING THE HEAT-SINK!!! The heat-sink has adhesive on it that is stuck to a smaller heat-sink which makes contact with the CPU chip. If improperly removed, the BGA chip can get ripped off the board and cause your board to be beyond economic repair. What we do is use hot air on the top of the heat-sink at around 300 degrees for around 20 to 25 seconds to loosen up the adhesive. This will make it easier to remove and will help prevent ripping traces on the CPU chip. (You must de-solder the large heatsink from the bottom as well) To find a replacement with proper software on this, you can purchase a chip on ebay from Coppell TV repair. (We do not sell these as repair kits as these failures very rarely occur)

Our 4th through 8th symptoms are all due to bad contact between the main CPU chip and the main board.
These CPU chips also called BGA which stands for Ball Grid Array run fairly hot. The chips themselves are very resistant and almost never fail, however after years of heating and cooling due to the Tv being turned on and off, microscopic cracks will form in the solder balls between the chip and the board. These cracks, will prevent data from going through and thus malfunctions will occur in many different ways dependent on which solder connections break first. There are two ways to fix this problem, a correct way, and an incorrect way. The incorrect way also the easier way would be to perform a reflow on the chip. What that means is to apply heat with the use of either an Infrared heating element or an oven. What a reflow means is you are heating up the solder balls to their melting point. As the solder balls heat up, they will expand and reconnect the cracked solder joints as they melt back together. The problem with this, is that they will almost never reconnect properly. This will only temporarily fix your issue and a repeat failure will come either within a few weeks or a few months.

What we have done at NicksTvs to properly fix these boards, is fully remove the chip from the board followed by cleaning up all the old solder from both the board and from the chip. From there we rework the chip by replacing all the old solder balls with new ones using softer, more malleable solder which is less prone to cracking in the future. I would not recommend performing this task unless you have access to a BGA rework station and experience using one. This is a very time consuming and delicate procedure. Once the BGA chip has been reworked, we tin the board, add a thin coat of special flux and reattach the chip. This repair procedure allows for extended life time on the board. This is why we are one of the only companies able to provide you with a full year warranty on these repairs. You will notice most repair centers only off 30-60 days and sometimes up to 90 days warranty on their repairs. This is because they only reflow the chip.

I hope this post/thread has helped people understand what goes on with these board and to avoid buying some of the advertised repair kits which contain in my opinion randomly selected components. Yes Zemtronix I am talking about you.

I have set this thread to email me every time someone writes a comment, so if you have further questions, please feel free to post and I will try my best to answer questions.

[Nick's Tvs]

Re: How to Fix your Vizio M470NV and M550NV

I don't check the thread that often so I am sorry if I am not getting back to you guys quickly.
I did want to point something out in the last question from Steve_Rogers_1970

The M550VSE is a completely different board with completely different parts.
This thread does not apply to it.

That failure you have is most likely software-related.

[dskall]

Re: How to Fix your Vizio M470NV and M550NV

You might read symptom 1. And go from there.

[Steve_Rogers_1970]

Re: How to Fix your Vizio M470NV and M550NV

Greetings Nick. I have a M550VSE where i can power it on via remote or side button and get the V logo on screen. then nothing else. it stay on that screen and and the only way to power off is to unplug. ShopJimmy says there is no EEPROM on it, so i'm curious about my options. i'm ok with resoldering for cold joints, but not sure where i should focus my efforts. any advice you can provide would be greatly appreciated.

[MrKazoo]

Re: How to Fix your Vizio M470NV and M550NV

Quick update. I've noticed that this red/magenta "shimmer" and "HDMI No Signal" fixes itself after the TV has been on for sometime. My theory is that heat causes the soder balls to expand eventually bridging the spotty connections.

[ivtec]

Re: How to Fix your Vizio M470NV and M550NV

Hi, I'm new to this forum but I've been lurking for a while. I just got a replacement mainboard and I've attached images to show what's happening. The picture would flicker and it would seem to fix itself after a few minutes. It's not limited to HDMI. I would also randomly get HDMI no signal but eventually does come back. I'm starting to suspect that the main CPU is on its last legs and needs to be re-balled. Any idea what could be causing this? Any help would be greatly appreciated.

I fixed my Vizio M421VT that would have a symptom of pic scrambled, i heated the BGA with a Heat Gun both sides of the board, and added 2 fans 5 v dc on the back against the BGA and it's been good ever since.

[MrKazoo]

Re: How to Fix your Vizio M470NV and M550NV

*delete this post*

[MrKazoo]

Re: How to Fix your Vizio M470NV and M550NV

Hi, I'm new to this forum but I've been lurking for a while. I just got a replacement mainboard and I've attached images to show what's happening. The picture would flicker and it would seem to fix itself after a few minutes. It's not limited to HDMI. I would also randomly get HDMI no signal but eventually does come back. I'm starting to suspect that the main CPU is on its last legs and needs to be re-balled. Any idea what could be causing this? Any help would be greatly appreciated.

[Nick's Tvs]

Re: How to Fix your Vizio M470NV and M550NV

I would not advise you to do it if all you use is top heat. Use bottom heat as well. In fact, most of your heat should be coming from the back of the board. If you have a heat plate or preheater you can use I highly recommend that and then use your top air to help assist for the last part of the reflow after your board has had a chance to heat up close to temp.

So if you don't have a proper rework machine and you need to do this on the fly, I would suggest have your board preheated to a minimum of 150c and then reflow the BGA with your top air at say 250c or so. Realistically you don't need to go that high but that's assuming a good environment with high-end equipment.

Quick tips
Use no-clean flux, don't breathe in the fumes, don't touch the board after you do this. Turn off your bottom heat and let it cool down for 20 minutes. You do not need to remove it from the bottom heat, just let it cool down slowly on it. You might knock some stuff off if you try to move it.

[DigZworld]

Re: How to Fix your Vizio M470NV and M550NV

Have a handful of these machines that need to be fixed. Nick's has been a great resource. I just got a new hot air station. Can I reflow the bad part with this?
Thanks in advance.

[Nick's Tvs]

Re: How to Fix your Vizio M470NV and M550NV

That audio issue is still going to be a BGA related failure due to the cracked joints between the circuit board and the chip.

[Dodgeman201216]

Re: How to Fix your Vizio M470NV and M550NV

This forum is awesome I sat down and read through this entire thread and then took a torch to the main board of my tv not directly on the board obviously but it fixed my vizio 3D 55” tv so thank you guys for the information

[nomoresonys]

Re: How to Fix your Vizio M470NV and M550NV

Hi Nick,

I see this is pretty old thread. Hope your still active on this forum!!

I have a Vizio MV550 with video/audio issues.
symptoms are:
1. Audio and Video randomly cut in and out and at times will work for a long period of time
2. I changed cables and inputs in different HDMI's

I have tried a few other things but need direction to finalize the repair I need to make
Don

Could be a faulty capacitor.

[Dedge]

Re: How to Fix your Vizio M470NV and M550NV

Hi Nick,

I see this is pretty old thread. Hope your still active on this forum!!

I have a Vizio MV550 with video/audio issues.
symptoms are:
1. Audio and Video randomly cut in and out and at times will work for a long period of time
2. I changed cables and inputs in different HDMI's

I have tried a few other things but need direction to finalize the repair I need to make
Don

[ngth82]

Re: How to Fix your Vizio M470NV and M550NV

Hi Nick -

What's the center-to-center ball pitch of this BGA? What ball size do you use when you reball the device?

Thanks,
Thomas

[Newbie62]

Re: How to Fix your Vizio M470NV and M550NV

Hey Nick Thanks for this post !
I picked up a free M470NV that had the flashing VIZIO logo on the bottom front of the tv.
It would flash 25 times, hang onto the white light on the 25th flash for about 30 seconds and go to the stby. circuit.
After baking the main board in the oven wrapped in aluminum foil @ 390° for 12 minutes and of course the tv turned on but the right half of the screen was white with no image so I cleaned and switched the LCD to Tcon ribbon cables and got a full screen image but the right side still has a white hue to it.
My question is that still a faulty main board.
I am very aware that this is a temporary repair !
The image below is the end result.

[nomoresonys]

Re: How to Fix your Vizio M470NV and M550NV

I believe that's your mainboard but I think 65 bucks for a 37 inch mainboard is outrageous: https://www.ebay.com/itm/Vizio-3637-...MAAOSwFdZcr3ri

[nomoresonys]

Re: How to Fix your Vizio M470NV and M550NV

Nice, I would install a fan on the back cover right where your bga is so it can run as cool as possible, the problem is they overheat a lot and that messes up the solder ball connections and a lot of times a second heating doesn't work

[wgrimes]

Re: How to Fix your Vizio M470NV and M550NV

Nomoresonys - Yes, TV is 37 inch.

Borrowed a heat gun and heated both sides of the board for 4 minutes per side. Put it all back together and IT WORKED!!! Don't know for how long. Thanks for all your help.

[nomoresonys]

Re: How to Fix your Vizio M470NV and M550NV

Is your tv a 37 inch screen?