Vizio M43-C1 No Backlights

[johnboiles]

Re: Vizio M43-C1 No Backlights

@howardc64: how long ago did you oven reflow those last two TVs? How long have they been operating for after the relow?

I was looking around for a replacement board and it seems they're out of stock most places. There are some on eBay that are used and >$100. Any surprising sources for parts other than Googling + eBay?

My M50-C1 has a LTCWSPBR* serial number. The main board has the nubmers `GXFCB0QK012020X` and `715G7288-M01-000-005K`. Though from looking around online it looks like the part number `756TXFCB0QK0120` should also work on my tv.

[howardc64]

Re: Vizio M43-C1 No Backlights

375F is 190C, lead free solder melts at 423F or 217C, it's not surprising your oven reflow isn't lasting.

Good point based on science! Don't know how long oven reflow method will last yet. Chose 375F-400F based on most internet postings on oven reflow for TV and laptop main boards. Wondering if something like 425F for 5min in an oven is safe on these boards?

Of course oven temp control isn't great and we don't really know what temps are at the BGA balls. Best would be a professional BGA rework station with precise temp, thermal profile, and much shorter duration of course but not really available to us consumers and not worth paying a pro to fix these cheap TVs. Really only fixing these to keep it out of landfills. These Vizio TV main boards are lasting between 2-5 years max.

[howardc64]

Re: Vizio M43-C1 No Backlights

@howardc64: how long ago did you oven reflow those last two TVs? How long have they been operating for after the relow?

I was looking around for a replacement board and it seems they're out of stock most places. There are some on eBay that are used and >$100. Any surprising sources for parts other than Googling + eBay?

My M50-C1 has a LTCWSPBR* serial number. The main board has the nubmers `GXFCB0QK012020X` and `715G7288-M01-000-005K`. Though from looking around online it looks like the part number `756TXFCB0QK0120` should also work on my tv.

I just did mine and been using it only a couple of days. During repair research, found this guy who claim it worked for 4mo and ongoing.. This is a P502UI-B1E (one of my dead Vizios) and basically same board design as the 2015-16 Vizio M D P series.

https://www.ifixit.com/Answers/View/...!#answer580091

I do plan to avoid smart TV functions in case they increase the temps of the BGAs (I didn't test but suppose I could while I run the TV with backcover off). The smart apps aren't very good compared to my fireTV anyways. Just watching Coax Antenna HDTV for an hour is 140F on the heatsink where the BGAs are with TV backcover off. Currently trying out some fan cooling solutions. Just not much space back there. Switched 12V source is available on top of the main board (on the 2x6 connector pinout next to wifi connector).

BTW, My 2016 D50U-D1 has exact same main board # as your M50-C1 (ending in 2020X) But I wonder if EEPROM software is the same. You might check EEPROM sources for these 2 TVs to see if they are the same. I tried a 2030X before and it didn't work although I suspect I received a bad board. I do see a 2020X board for D50U-D1 from shopjimmy currently or $43 on ebay (zoom magnification over the board sticker) Maybe contact them to confirm it will be 2020X board (instead of 2030X or 2040X) and whether it will work on M50-C1 (don't know if they know)

https://www.ebay.com/itm/Vizio-756TX...Cclp%3A2334524

[johnboiles]

Re: Vizio M43-C1 No Backlights

@howardc64 thank you so much for the info. Really helpful!

One more question: how did you remove the heatsink? Mine is soldered on. Did you desolder yours before reflowing? I'm wondering if I could just snip it off then modify it to use screws instead. If I end up needing to toast this thing again, I'd like to try to do it right and take the heatsink off (and probably also get some low viscosity flux).

My repair is holding out 2 days in. One quirk my 6yo noticed is that the power LED no longer works but the rest of the TV is still working!

[howardc64]

Re: Vizio M43-C1 No Backlights

One more question: how did you remove the heatsink? Mine is soldered on. Did you desolder yours before reflowing? I'm wondering if I could just snip it off then modify it to use screws instead. If I end up needing to toast this thing again, I'd like to try to do it right and take the heatsink off (and probably also get some low viscosity flux).

My repair is holding out 2 days in. One quirk my 6yo noticed is that the power LED no longer works but the rest of the TV is still working!

Soldered on heatsink is definitely a challenge to remove. Sink soaks up all the heat you apply to it so very hard to melt the solder. Friend has a Hakko desoldering tool (An iron with holed tip + powered suction) This + flux get most of the solder off. Even then, still needed yet another iron with 4 hands to get the heat sink off

I also thought about threading the heatsink back on. But couldn't find a small tap+die or self threading nut with small enough washer diameter (couple of legs are pretty close to component and traces) You can snip the legs off, drill a hole and do your own. Just note not much space (components near some holes) and top of heat sink only has ~3/16" clearance from TV's back case. I elected to solder back on (clean the old lead free solder off and use lower temp leaded solder) with a little bit of solder for easier removal later. Still holds pretty well.

Been thinking and experimenting with fan cooling. Positioned fan in various positions with the back off and discovered sucking the heated air radiating from heatsink isn't very efficient. Blowing on the heated area is always more efficient. But in general, the challenge on these thin TVs is same tiny thin space as laptops. So best solution would be to remove the current heat sink, figure out how to mount a place on top of BGAs, use heat pipes to carry heat away with flat fans + heat fins to exhaust outwards. Laptops does all this in a long horizontal assembly with the heat exhaust in plane to this assembly. On this TV, you would want a horizontal assembly but exhaust perpendicular to the assembly and out the back of the TV case. Anyhow, only have thought about the problem for now. Heat sink is about 120F and BGA area 140F with the TV running for awhile. Not super hot but heat is just not efficiently taken out.

On your power LED, might check next time you have all the connections on correctly on the bottom corner of the board. Can't remember which one was power LED but recall a flat flex cable was tricky to get on correctly.

[GeorgeT]

Re: Vizio M43-C1 No Backlights

Success! My fake Amtech flux finally arrived so I attempted the re flow on the 2 BGA's on my Vizio D55u-D1 motherboard.

Steps I took...
1) Removed the heat sink & old thermal paste
2) Removed the 4 rubber spacer pads under the board. Major pain to get them off cleanly.
3) Placed board in preheated oven 100c/200f for 10 minutes to remove moisture and warm whole board up.
4) Removed board from oven, then applied flux around all 4 sides of each BGA. I tilted the board and heated the flux with the heat gun for a few seconds so the flux would flow under the chips. Not sure how much flux got under there but I used a liberal amount on each side.
5) Laid heat probe on first BGA.
6) Heated chip and surrounding board to 150c/300f for 2 minutes. Moving the heat gun in a circle pattern. I used a Wagner heat gun on low fan setting.
7) Re flowed the chip at 217c/422f for 1 minute. This was a little tough to accurately monitor because the probe sent with the meter only officially went up to 200c. I would raise and lower the heat gun from the chip to keep the temperature close to 217c target.
8) Followed steps 5,6, and 7 on the other BGA chip.
9) When finished, I used a piece of cardboard and fanned the board to cool everything down
10) When board was cool, I used some alcohol to remove any hardened flux from the top of the chips that may have migrated up there.
11) I applied some old Radio Shack thermal compound to the chips and reinstalled the heat sink and the 4 rubber pads on the bottom of board.
12) Installed board back in TV and turned on. Picture came on!!!

Who knows how long this repair will last, but it was fun getting it this far. Thanks to the advice on this forum and keeping me focused on the BGA's.

[diif]

Re: Vizio M43-C1 No Backlights

Nice work GeorgeT, with preheating the board and following the profile as close as possible, it should last a decent amount of time.

[GeorgeT]

Re: Vizio M43-C1 No Backlights

Thank you diff for the suggestion to get a temperature meter and follow a profile. Without that I was just guessing and getting nowhere. Also the preheating of the board to prevent popcorning was vital. Without these suggestions, the TV would be going to the recycling center.

[johnboiles]

Re: Vizio M43-C1 No Backlights

Ok update: my cowardly 375F 8min toaster oven bake lasted a smidge over 7 days. Interestingly the power LED came back after a few days for some reason haha.

I tried briefly to take off the heat sink tonight with my fine-tipped Weller and some solder wick but I don't think I have anything nearly strong enough for the job. I also briefly attempted to drill through the heatsink standoffs to replace them with screws but that wasn't proving to be very easy either.

I applied a bunch of flux around the BGA chips and I'm going to do 425 for 10 mins and see what happens.

[howardc64]

Re: Vizio M43-C1 No Backlights

Ok update: my cowardly 375F 8min toaster oven bake lasted a smidge over 7 days. Interestingly the power LED came back after a few days for some reason haha.

I tried briefly to take off the heat sink tonight with my fine-tipped Weller and some solder wick but I don't think I have anything nearly strong enough for the job. I also briefly attempted to drill through the heatsink standoffs to replace them with screws but that wasn't proving to be very easy either.

I applied a bunch of flux around the BGA chips and I'm going to do 425 for 10 mins and see what happens.

Mine still working after maybe 15 hours of use. You might try the GeorgeT's process with temp probe + heat gun + heating profile. But it does require taking the heatsink off. I suppose oven bake at 425F is just gross overkill in comparison (more components heated for longer profile) I guess the question is does it damage the board? I unfortunately don't have extensive experience or comparison.

Debating if I should get a low cost IR rework station. At least get good temp+profile or maybe even attempt BGA removal and use leaded solder balls which should yield much better reliability. Seen 4 Vizio TVs, 3 GPUs, and 1 phone BGA solder ball failures so far. Phone is even harder with underfills.

[johnboiles]

Re: Vizio M43-C1 No Backlights

I tried to do a bit of a profile. I used some Kester flux I had around (probably not low-viscosity?) and squirted that as best I could under the heatsink to the sides of the BGA chips. Then I did the following in the toaster oven

200F preheat 5 min
350F for 3.5 min
450F for 3 min

When I first put everything back together, I was getting spazzy artifacts that looked like some kinda frame sync thing wasn't firing. Then after a few minutes of turning it off and on again it started working. Probably when it fails again I'll get a little more aggressive until I definitively destroy it.

[howardc64]

Re: Vizio M43-C1 No Backlights

I tried to do a bit of a profile. I used some Kester flux I had around (probably not low-viscosity?) and squirted that as best I could under the heatsink to the sides of the BGA chips. Then I did the following in the toaster oven

200F preheat 5 min
350F for 3.5 min
450F for 3 min

When I first put everything back together, I was getting spazzy artifacts that looked like some kinda frame sync thing wasn't firing. Then after a few minutes of turning it off and on again it started working. Probably when it fails again I'll get a little more aggressive until I definitively destroy it.

FYI, I wouldn't trust the oven temps unless its convection. When my little toaster oven dial is at 380F, laser temp gauge shows BGA and nearby area at 420F. Your symptoms sounds like over heating. BTW, fixed son's Nintendo switch today baking logic board + eMMC card for 7min so thats 3 for 3 and we'll see how long it last.

Just bought a T862++ low end BGA rework station after seeing so many BGA solder ball failures. Will practice on my popcorned Vizio board. Still need to get BGA holder, stencil, and solder paste. Already got a good hot air station.

I will say this... oven reflow seems to be safest if no expertise. No need to worry about popcorn and low chance of overheating. Hot air gets a bit trickier (moisture removal, temp probe etc) And I suppose rework stations and reballing require the most equipment and skill.

[howardc64]

Re: Vizio M43-C1 No Backlights

Been doing more research on reflow+reball. Here is a quick summary although I'm by no means an expert. Here is a video on what happens on 2ndary reflow which is why pros say proper repair is remove BGA+reball

https://www.youtube.com/watch?v=aRUg...nnel=BobWillis

Regarding reball, probably need better IR welding machines to pull BGA off properly without damaging it and the board. My cheap T862++ (still almost $200) hasn't got the power and control to remove large BGAs off properly. Thus its mainly used for better than oven reflow (with proper knowledge on thermal envelop)

Heard a tech on video say NASA only sends leaded soldered parts into space haha.

Anyhow, for most of us consumers, oven is probably best we can do without spending for a repair shop. Curious what the life extension from the 4 reflow methods are : heat gun, hot air station, oven, and IR reflow. Curious if these < $100 repair services we see on ebay are IR reflow or full reball? Probably the former?

[BigRnastY]

Re: Vizio M43-C1 No Backlights

I have the same issue as you howard with the same model M43-C1. No image, flashlight test didnt work, blinking lights the whole works.

I purchased a mainboard as I did not stumble upon this thread until today but I replaced the mainboard as I am ultra new to this stuff and had to watch a youtube video just to replace the mainboard.

I replaced the board correctly I believe and it has the same issue!

Did I do it wrong or get a faulty board? is there a reset I should maybe do?

I ordered the correct board as well. It was like $70

If anybody can help that would be greatly appreciated!

[johnboiles]

Re: Vizio M43-C1 No Backlights

I had a replacement board pop up on my eBay saved search for $50 and pulled the trigger on it. But my most recent janky leave-the-heatsink-on toaster reflow is still working a month in so it's still in its box!

@BigRnastY I haven't done a replacement yet so I can't speak definitively to whether there are any tricks, but I think it _should_ just work. If I were you, I'd try to send the board back and get a refund.

[howardc64]

Re: Vizio M43-C1 No Backlights

My stats on 2 heatsink removed toaster reflow wo flux has been working so far (1+ mo). One board does have problem restarting immediately after longer use. Once it cools off, starts up fine. I'll probably reflow that one soon again using my newly acquired cheapo IR station with some flux.

@BigRnastY, no reset is necessary. if you/friend have VOM meter, check the PSU's power supply output to the main board and disconnect the T-con board connection (per my post #9 on the thread) if those are ruled out, its likely failed main board and perhaps the ebay board had the same failure. I don't think anyone is intentionally selling bad boards, once the TV is gutted, can't really test anymore.

I've seen 3 Vizios with these same basic main board design fail now. 2 from 2015 and 1 from 2016. Probably last 3-5 years depending on use before the 2 BGA balls fail.

[howardc64]

Re: Vizio M43-C1 No Backlights

Been doing more research on reflow+reball. Here is a quick summary although I'm by no means an expert. Here is a video on what happens on 2ndary reflow which is why pros say proper repair is remove BGA+reball

https://www.youtube.com/watch?v=aRUg...nnel=BobWillis

Regarding reball, probably need better IR welding machines to pull BGA off properly without damaging it and the board. My cheap T862++ (still almost $200) hasn't got the power and control to remove large BGAs off properly. Thus its mainly used for better than oven reflow (with proper knowledge on thermal envelop)

Heard a tech on video say NASA only sends leaded soldered parts into space haha.

Anyhow, for most of us consumers, oven is probably best we can do without spending for a repair shop. Curious what the life extension from the 4 reflow methods are : heat gun, hot air station, oven, and IR reflow. Curious if these < $100 repair services we see on ebay are IR reflow or full reball? Probably the former?

Here are more follow up info to reflow

Stats on older Macbook Pro's nVidia 8600 GPU reflow revealed the failure was junction inside the BGA (probably between the die and BGA package?) So reflow just temporarily fix that junction and reball is insufficient fix. Don't know if these Vizio BGAs have similar issues. Anyway, low cost of the board/TV yield little reballing stats. Here is some info on this this internal junction failure

https://www.youtube.com/watch?v=1AcE...=LouisRossmann

Beyond toaster oven reflow, next better reflow is probably an IR station with flux. Lots of XBOX/laptop GPUs a few years back gets this type of fix, just a few burst of IR heat to reflow temps with low residue flux fed under the BGA. Don't know if this flux can help oven reflows (might just boil off before reflow temp is reached? as low residue flux is really liquidy)

There are $30-$50 reflow controller mods for toaster ovens to convert them into a reflow station. Basically use a thermal couple and adjust the heating elements to follow a solder melting heat profile (gradual increase to about 160C (to properly thermal expand the board) before spiking up briefly above solder melting temps, and proper cool down) . Hobbyists use these to solder surface mounted components. Probably yield better results.

Reflowing without reballing also means any oxidized cracked surfaces aren't resoldered well at all. This is why good soldering effort require cleaning off all soldering surfaces with fresh solder+wick off etc. Hence, pros say reball is the only real fix (BGA internal junction issue not withstanding)

[nomoresonys]

Re: Vizio M43-C1 No Backlights

I had a replacement board pop up on my eBay saved search for $50 and pulled the trigger on it. But my most recent janky leave-the-heatsink-on toaster reflow is still working a month in so it's still in its box!

@BigRnastY I haven't done a replacement yet so I can't speak definitively to whether there are any tricks, but I think it _should_ just work. If I were you, I'd try to send the board back and get a refund.

I would at least test the board you bought, if it is faulty and you wait too long, you probably won't be able to get a refund.

[edhuk]

Re: Vizio M43-C1 No Backlights

This thread on problems with the VIZIO M43-C1 appears to run from when this 4K set came out in 2015 to now.
Clearly looks like the main board was a bad design and repair shops as well as DIY people such as myself are having to try to catch up.
I purchased a VIZIO M43-C1 with no picture/sound/BL
Rookie error: BEFORE testing voltages I ordered a power board. It was cheap so I thought I would give it a try as so many of these sets seem to be fixed with just the power board.
HOWEVER on checking voltages all was good.
Having read this entire thread, the MAIN BOARD 715G7288-M02-000-005T is the most likely candidate.
As later posters have found, this board is impossible to find in stock by the usual sellers.

So, I guess, like many of you, I'll just have to wait to see if the board becomes available again which looks increasingly doubtful.

[jjanssen7]

Re: Vizio M43-C1 No Backlights

The M43-C1 is a great candidate for a panel swap. The LCD panel fits into several Sharp and Insignia 43" models manufactured in the similar time period. So just buy one of those "cracked screens" and swap the panel and tcon over. No mods needed.

Just a thought....