Vizio M43-C1 No Backlights

[ziddey]

Re: Vizio M43-C1 No Backlights

Has a main board part interchange ever been determined? Just picked up an m50-c1 that needs a new board. Bad board is gxfcb0qk012040x / 715g7288-m02-000-005t.

Found https://www.tvpartstoday.com/756TXFC...fcb0qk0120.htm which lists "756TXFCB0QK0120 Vizio Main Board, 756TXFCB0QK012, 715G7288-M02-000-005T, GXFCB0QK012040X, GXFCB0QK012030X, GXFCB0QK012020X, CBPFETEKX6C, M50-C1"

I do see that the d50u-d1's gxfcb0qk0220030x is much cheaper and more readily available. Looks like a similar board, but the picture shows the cn210 connector is populated on this model.

edit: shopjimmy states "PLEASE NOTE: The main board you receive may or may not have connectors at locations CN210, CN212 and CN203. These connectors are not used in model M50-C1 and will not affect functionality. "

[dsant90]

Re: Vizio M43-C1 No Backlights

Just to add that for the D55u-d1, I only did it to one CPU, not two

[dsant90]

Re: Vizio M43-C1 No Backlights

I had the same problem as Neilc6 with my M43-c1. I removed the Mainboard and its heatsink, covered the components around the cpu to shield them from the heat. Pointed the heater at the cpu while monitoring its temperature with a laser thermometer pointed at it. Once its temp reached 121 degrees C, I began timing it with a stop watch and kept the temp between 121 and 130 for 5 minutes. Then repeated the procedure with the second CPU. Then let it cool to room temp and put everything back together. Tv is fixed! I don't know how long it will last, but I did the same with a Vizio D55u-D1 and that is still working after two months. I am not a technician or tv repair expert and I know nothing about the internal architecture of a CPU, but I learn about this from a Youtube video posted by Louis Rossmann who is a laptop repairman. Using this method you don't expose any of the other components to intensive heat.

[Dananar]

Re: Vizio M43-C1 No Backlights

See post #5 on this page from jjanssen7.
If the panel + T-con board swap works...I believe swaping the PS + MB + T-con from another M43-C1 with a different serial starting characters should work ?. Ex. From a Lttwseac to lttwspar....

[Dananar]

Re: Vizio M43-C1 No Backlights

Wondering if changing main board from a M43-C1 lttwspar serial with the one for lttwsear will work...

[howardc64]

Re: Vizio M43-C1 No Backlights

Proper reflow with good BGA reflow station is certainly the best solution but inaccessible to most people budgeting < $100 for fix (new disposable 50" UHD TV @ $200)

Cheap toaster oven reflow temp is imprecise with temp setting not matching temp @ BGA. Thats why I proposed 375F-400F (below lead-free melting temp). Temp around BGA could be slightly higher (my IR temp gun (what I had, obviously not good as thermal couple) shows 400F+ @BGA with 375F setting on my cheap toaster oven)

Removing soldered on heat sink is difficult with sink drawing away heat from the soldering iron. I used 2 irons (1 is $200 Hakko desoldering gun with a pulsed pneumatic suction tip), 2 people and gradually worked free all the solder points. Used limited amount of leaded solder to install in case need to remove again.

Tried fan cooling. Small fan hidden inside TV don't have enough airflow to achieve any temp reduction. Probably need to cut back of panel (or leave the back off all together), use big fan (more flow with lower noise) to make any temperature difference. Fan won't rescue a board that needs reflow so still need to reflow.

In my experience, toaster oven reflow lasting much longer than heat gun reflow so far. Primarily because I didn't dare to apply heat gun too much (with heatsink off) as it can easily damage the BGA+board. Toaster oven offers better temp "control" even if horrible by good BGA reflow station standards.

Anyway, just offering cheap none repair shop TV owner solution My heat sink off toaster oven reflow devices (2 TVs, 1 Nintendo Switch) are all still working as well. TVs seen about ~100 hours use since reflow so not heavily used.

[johnboiles]

Re: Vizio M43-C1 No Backlights

My simple heatsink-on toaster reflow from mid December is still working fine! I'm truly surprised! If you don't have the skill or tools to get the soldered-on heat sink off, just try a toaster reflow with it on first!

[nomoresonys]

Re: Vizio M43-C1 No Backlights

Very good info DXseekerMO, thanks.

[DXseekerMO]

Re: Vizio M43-C1 No Backlights

I find on Vizios when there is 15-19V on the 12V line and there is no 12V at the timing control board "VIN" test point that the Main Board is the culprit. This includes the Viz M50-C1.....and SO MANY MORE!

If your M50-C1 Viz has multi-colored pixels at either lower corner of the screen when turned on the screen is probably shorted. Try detaching one FFC from the T-CON at a time and see if the screen is white on one side and the picture comes back upon the other. Whichever FFC is detached when half the picture returns is the shorted side. I now use an M50-C1 with a shorted screen and 1 FFC taped over 6 traces as a tester TV.

Once you find which side is shorted cover at least 6 traces on the outboard side of the FFC with scotch tape, re-insert the FFC in to the T-CON and see if you have a full picture. If not, cover one more trace at a time until the picture returns.

M50-C1's that appear to turn themselves on over and over with no picture or multiple flashes of the status light probably need a Main Board.

M50-C1's need Power Supplies a lot less than what you think!

Unless the T-CON fuse is blown the T-CON is most likely good on your M50-C1

The NUMBER ONE FAILURE on the M50-C1 is the Main Board.

[diif]

Re: Vizio M43-C1 No Backlights

common.. only BGA reball will last years... others are could be days or more.. the problem its the soldering pasta when they apply it to the boards at first time before installing parts on it and then boards go to oven. in this manufacturing procedure allot in china they didn't used camera robot after the stencil pasta step to exam the pasta placing amount, even whom used this camera step where it should adjust to not less 95%. some reduce this tolerance even to 60% if they have busy orders. so any boards manufactured under this wrongdoing will face BGA issue. so what the decent reflow can do when the paste are so little. !!

You highlighted the most important bit. Decent reflow board preheated, accurate temperature profile and flux, why shouldn't it last as long again ?

Yes, replacing the balls with lead provides a much longer life, but on some things it's not worth it. Maybe they are junked but I don't hear anything back.

[alfatv]

Re: Vizio M43-C1 No Backlights

How hot do they get ?

I measured 65 degC on top of heatsink with back cover removed.

[diif]

Re: Vizio M43-C1 No Backlights

Have you done it for this particular M43-C1?
The problem is with 2 chips running very hot which leads to new failures.

I am thinking of attaching 2 heatsinks with fans like this in place of original heatsink
https://www.aliexpress.com/item/4001080930094.html

I've not seen a Vizio over here but I've reflowed and quite a few TV mainboards and have yet to have one back.

It's about 5 years old ? there's no reason a well done reflow shouldn't last as long. You can add a fan and heatsink although, it will still get hot and it will still expand and contact when going from off to on and vice versa. How hot do they get ?

The biggest cause of failures of home reflows is they weren't done hot enough from the temperatures I keep seeing them done at.
I'm ignoring those that kill them with a heat gun.

[alfatv]

Re: Vizio M43-C1 No Backlights

Without intentionally being rude, don't be discouraged by amateurs that aren't doing it right.

Lead free solder melts at around 217°C or 422°F.

A decent reflow will last years, I know as I've done plenty.

Have you done it for this particular M43-C1?
The problem is with 2 chips running very hot which leads to new failures.

I am thinking of attaching 2 heatsinks with fans like this in place of original heatsink
https://www.aliexpress.com/item/4001080930094.html

[Diah]

Re: Vizio M43-C1 No Backlights

Without intentionally being rude, don't be discouraged by amateurs that aren't doing it right.

Lead free solder melts at around 217°C or 422°F.

A decent reflow will last years, I know as I've done plenty.

common.. only BGA reball will last years... others are could be days or more.. the problem its the soldering pasta when they apply it to the boards at first time before installing parts on it and then boards go to oven. in this manufacturing procedure allot in china they didn't used camera robot after the stencil pasta step to exam the pasta placing amount, even whom used this camera step where it should adjust to not less 95%. some reduce this tolerance even to 60% if they have busy orders. so any boards manufactured under this wrongdoing will face BGA issue. so what the decent reflow can do when the paste are so little. !!

[R_J]

Re: Vizio M43-C1 No Backlights

Thanks for your quick reply!

I was considering the reflow route but many posters here say it won't last long even if the reflow works.

In looking at the heat sink it appears to be soldered to the underside of the board at 5 points. If I remove the 5 blobs of solder the heat sink should come off, right. I could then use the heat gun route to reflow the two main chips.

If something is not working and trying a repair MIGHT make it work, it is worth a try. Have a closer look as I believe there are 6 solder connections for the heatsink. It might also be the U202 eeprom ic. shopjimmy has them available $15.00 If you go this route there are 2 different ones depending on the board numbers.

[diif]

Re: Vizio M43-C1 No Backlights

Thanks for your quick reply!

I was considering the reflow route but many posters here say it won't last long even if the reflow works.

In looking at the heat sink it appears to be soldered to the underside of the board at 5 points. If I remove the 5 blobs of solder the heat sink should come off, right. I could then use the heat gun route to reflow the two main chips.

Without intentionally being rude, don't be discouraged by amateurs that aren't doing it right.

Lead free solder melts at around 217°C or 422°F.

A decent reflow will last years, I know as I've done plenty.

[edhuk]

Re: Vizio M43-C1 No Backlights

Heat (reflow) main board in toaster oven @ 375F for 8min (board surface temp will read ~400F using laser temp gun). Make aluminum foil ball for feet to keep board/components off of metal tray. Its the best DIY solution without BGA reflow tools.

Better if can remove heat sink before reflow but most of these main board's heat sink is soldered on and very difficult to remove.

Fixed 2 of these Vizio boards and a Nintendo switch main board with this method and been running for a few months now

Thanks for your quick reply!

I was considering the reflow route but many posters here say it won't last long even if the reflow works.

In looking at the heat sink it appears to be soldered to the underside of the board at 5 points. If I remove the 5 blobs of solder the heat sink should come off, right. I could then use the heat gun route to reflow the two main chips.

[jjanssen7]

Re: Vizio M43-C1 No Backlights

What are those models please

Rather than messing with reflows that in my experience only last a couple of months (at best) and therefore cannot be resold, I take the panel out of M43-C1 and put them in a new but cracked screen unit. Substitutes are:

Toshiba 43L621U
Toshiba 43LF621U
Insignia NS43DR710 (Warning, this model has bad LED lifetime too)
Sharp 43LB591 or the next year's model too (43L711?)

In all these cases, the screen and tconn together are swapped. No modifications required beyond that.

[howardc64]

Re: Vizio M43-C1 No Backlights

Heat (reflow) main board in toaster oven @ 375F for 8min (board surface temp will read ~400F using laser temp gun). Make aluminum foil ball for feet to keep board/components off of metal tray. Its the best DIY solution without BGA reflow tools.

Better if can remove heat sink before reflow but most of these main board's heat sink is soldered on and very difficult to remove.

Fixed 2 of these Vizio boards and a Nintendo switch main board with this method and been running for a few months now

[edhuk]

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....

Great suggestion!

The $20 power supply board arrived today and, as predicted, didn't fix the problem. Exact same symptoms Fading power light then 15 flashes just like the existing board that tested with good voltages.

So, I'll keep looking for a main board and may try a reflow using my heat gun. Not sure if I'll try oven baking as I see it melts the plastic parts on the main board as per a YouTube video.

Cheers!