Vizio M50-C1 no picture

[starionesir]

I have a model Vizio M50-C1 that powers on fine with back lights but no picture. I removed the back and didn't see any obvious signs of damage. I replaced the t-con board with a known good board, same model as original. No change.

I did notice that when you push a button like menu or volume the screen brightens in the area where you would normally see the picture. It just makes a slightly brighter whitish area. So it does respond to inputs from the remote. Out of curiosity I unplugged the t-con and powered the tv back on again. Odd thing is it functions the same. So the area that was getting brighter with hitting the inputs on the remote must be from the back lighting as the t-con was unplugged and the led panel was not powered on. So now I'm wondering if I have a bad logic board and it not feeding power to the t-con. I've been trying to locate a service manual or test points for checking voltages going from the logic board to the t-con so I don't end up buying a logic board only to find out that doesn't fix the problem.

[budm]

Re: Vizio M50-C1 no picture

Can we ate least see the pictures of the whole backside of the TV so we can see what we are dealing with?
How many cables between the TC-ON and the LCD panel does it have? You may have to have those cable connected one a time to see what happen and also need to check to see if the T-CON is getting 12VDC for it to run or not.

[starionesir]

Re: Vizio M50-C1 no picture

I'll see if I can have my wife take some pics and send them to me so I can post them. I can tell you two cables from t-con to panel. I wanted to check for 12 volts at t-con to see if the logic board was powering it on but wasn't sure where to test.

[starionesir]

Re: Vizio M50-C1 no picture

Here is the back.

[R_J]

Re: Vizio M50-C1 no picture

The best place to check for the voltage is on the t-con is the fuse, If this is your board it a white smd marked as F101

Depending on your tv's serial number, shopjimmy has complete board sets for around $80.00
This kit is compatible with TVs with serial numbers beginning with LTM6SRAR or LTC6SRAR

although the t-con by itself is only $15.00

[starionesir]

Re: Vizio M50-C1 no picture

Is it the part labeled F101?

[R_J]

Re: Vizio M50-C1 no picture

Yes

[starionesir]

Re: Vizio M50-C1 no picture

O I feel dumb I didn't notice you posted the picture. Yes that board is the one I have. I did replace the board and that didn't change anything which is why I'm leaning towards something else like the logic board not powering up the t con board.

I assume I'm looking for 12 vdc on the fuse to see if the logic board is commanding it to power on? If I don't have any power on either side of the fuse then next step would be to troubleshoot the logic board?

[Andrew F. Ali]

Re: Vizio M50-C1 no picture

You still have not measured for 12Vdc on the T-CON Bd.at F101.

[starionesir]

Re: Vizio M50-C1 no picture

No I had not measured for voltage yet. I was not sure where I was looking for voltage and how much voltage. I couldn't find a service manual online for my model tv.

As soon as I get home in next couple hours I'll check for power at the fuse and report back my findings. If I don't have power where's the next spot to check on the logic board to see if problem lies there.

[starionesir]

Re: Vizio M50-C1 no picture

This is the main board I have. Currently not available from Shop Jimmy but I have found some used ones on Ebay.

[Andrew F. Ali]

Re: Vizio M50-C1 no picture

I have purchased used boards from e-bay and they were all good, as long as you match the Part No., the one on the white label, with the one you are going to buy.

[starionesir]

Re: Vizio M50-C1 no picture

That's what I've read. I hadn't pulled the trigger on one yet until I know for sure it needs a new logic board.

[yohnsee]

Re: Vizio M50-C1 no picture

I think it is too soon to look for a new mainboard.
As Ali said, you should measure voltage. I personally am leaning towards a Tcon and/or panel failure, altough you dropped a brand new Tcon there.
There is one more test you could make: hook it up via HDMI to a known good source (set-top box, laptop, anything that gives image AND sound), try to turn to AV from memory (your memory), and see if it produces sound. If so, then your motherboard is NOT bad. You said yourself earlier, it looks like the set responds to menu and other buttons with changing the intensity of the backlight (if I read that correct). That is also a sign of a working mainboard.

[starionesir]

Re: Vizio M50-C1 no picture

Thanks for all who replied. I checked for voltage at the t-con board and confirmed I had 12 volts. I also tried running the t-con board with only one ribbon cable at a time to see what happened. When I ran it with the right side unplugged I got picture as you can see in this image. So the one side of the screen is toast I'm assuming and from what I can see getting a new screen is not worth the hassle and cost.

[budwich]

Re: Vizio M50-C1 no picture

The tv may still be saveable as there are methods to get the full picture back. Are there bonded tab along the side of the panel... much like the tabs at the bottom of the set which connect bottom edge boards to the panel.... on the side, you may only see tabs and no boards.... might have to take the front bezel off to see the side tabs.

IF there are side tabs, you may be able to remove them IF the issue is with one of them... perhaps the bottom one if the picture is showing the dark spot in the corner and its not a crack in the panel itself. Lots of threads with this type of issue (side tab problems) and the resulting "save" by removing the tabs on the side.

[starionesir]

Re: Vizio M50-C1 no picture

Not sure exactly what your talking about with side tabs. Still new with tv repair. What part am I looking for? The side of the screen with no picture has the dark shadow in the corner. Not sure what the shadow means exactly.

[Andrew F. Ali]

Re: Vizio M50-C1 no picture

the tv may still be saveable as there are methods to get the full picture back. Are there bonded tab along the side of the panel... Much like the tabs at the bottom of the set which connect bottom edge boards to the panel.... On the side, you may only see tabs and no boards.... Might have to take the front bezel off to see the side tabs.

If there are side tabs, you may be able to remove them if the issue is with one of them... Perhaps the bottom one if the picture is showing the dark spot in the corner and its not a crack in the panel itself. Lots of threads with this type of issue (side tab problems) and the resulting "save" by removing the tabs on the side.

+100

[starionesir]

Re: Vizio M50-C1 no picture

Andrew F. Ali, what am I looking for so I can open it up further tonight to see if I can salvage it.

[yohnsee]

Re: Vizio M50-C1 no picture

First, try to power on the set with both ribbon cables removed.
Do you still see the dark dot/area in the corner? If NOT, then we can move on.
I'll try to explain, what budwich said. You have to disassemble the display, so you can access the bare LCD panel. You need to take off 2 or 3 bezels to get so deep. Then, inspect the panel (the better if you send pictures of it) on the bad side (left, if I remember correct). You should see tabs, flexible pcbs, name them as you want. They are only connected to the LCD panel, nowhere else. They are glued on with a special conducting glue. You have to lift them off on the bad side, they come off easily. Then clean the residues, put the tv together and test. We can help more, if you post pictures of every step you go further.