HELP PLEASE ... GPU HDMI = No Signal (DVI works)

Hello guys, I'm new to this forum!
I'm sure many of you are great problem solvers when it comes to PCs, so I need your help.

My current system:
Windows 10 PRO, 64bit
Intel i5 3570k - CPU
GA-Z77X-UD3H (rev. 1.1) - Motherboard
Seasonic 620w - PowerSupply
16GB(1600 Mhz) Corsair Vengeance DDR3 - RAM

The problem: When I connect an HDMI cable to my TV from my GPU, I get No Signal.

A more detailed explanation:
A few years ago I bought an MSI GTX 660 Graphics Card. The card worked just fine, connected it through DVI to my monitor... all good so far. Then I tried to connect it to my TV(32 inch LG LED) as a second monitor through the HDMI port. I got No Signal. No second monitor appearing in Display Settings, nor inside Nvidia Control Panel. Windows project to a second monitor(extended, duplicate) didn't work either... TV not recognized at all, nowhere, not even in device manager.
Then I tried the other DVI port on the GPU: that worked just fine. So 2 monitor setup worked: DVI to monitor and the TV was connected through the second DVI (with DVI to VGA adapter, because the TV has VGA). But I didn't like the idea of bringing sound to the TV with an extra cable... So I went a diferent route: I decided to connect my TV through the HDMI port on my motherboard. That worked just fine, we got signal.
So Internal GPU(HD4000 from the CPU) was supplying the graphics for the TV and my GPU was powering my monitor graphics. But I still didn't like the idea... picky...
At a later time, I tried the HDMI port on my GPU again, no success. A friend suggested I try to use the display port on the GPU and go with DisplayPort to HDMI to the TV(TV has HDMI). That didn't work either... No Signal...

In case you're wondering, the HDMI cable works just fine, HDMI port on TV works just fine. Same cable and tv port work through mobo HDMI or other sources like a laptop.

I also tried changing settings in the BIOS, with no success. Disabled the internal Graphics, disabled CSM support, tried what I read online.... no success. My conclusion: 2 dead ports on my GPU(HDMI and Display Port)... so stuck with re-enabling internal Graphics and running the TV through the mobo HDMI.

Some time has passed... a few years... And I sold my GTX 660... I bought a GTX 950. Put it in my system, latest drivers installed. Connected my monitor through DVI. All worked fine. Then I connected the TV through the HDMI port on this new GPU. Guess what? No signal... AGAIN!!! TV not detected...

What could be the problem? My motherboard? I updated the BIOS to the latest version, still no success...
I really don't know what to do...

Your help is much appreciated! Thanks!

I knew it was tv related as soon as I read the title... some tvs don't have the proper hdmi standards built in i had the same issue with a tv i just sold. try a different tv see if it works.

Thanks a lot for the reply!
Should it be the TV if it works through the motherboard HDMI port and also through a laptop HDMI port?

Well that's interesting.

Let me make sure I get this right: the TV gets a signal through HDMI when it runs through the motherboard, and a laptop, but not the GPU?

Then that is not the TV, that means either the cable (unlikely) or the 950.

I'm not sure if that would be a hardware issue or a driver issue.

Yeah. Works through other sources on same cable and TV port... And had the same problem on my old gpu(gtx 660) which i sold yesterday... I'm really stuck on this issue...

Could be some weird issue with the motherboard... but I frankly don't know what that would be. I would say the motherboard's PCI lane the 950 is in would be the issue, but if the DVI works I just don't know.

Just in case, can you try another PCI-E lane for your GPU if you have one?

Only one of my PCI-E slots works at 16x, the other two work at 8x and 4x... So that wouldn't work for me :(

My apologies if I'm missing a massive compatibility issue, but that should work.

I'd say at least try it for troubleshooting purposes, to see if it was the lane or not.

PCIe x8 will run a GPU...

HOLY SHIT I HAVE THIS SAME PROBLEM. I have tried and tried for weeks to fix it and could not find a solution. I'm at a loss and assuming the gpu is defective. If you find a solution please for the lover of god save me.

Guess what guys, I tried plugging in my monitor through the HDMI port on my GPU and it works! So it's got to be the TV like @SoulFallen suggested. I found a thread online that tells me how to update the TV's HDMI EDID info. I'll try to do that and get back with an answer. Thanks a lot for the suggestions!

@CapnFox yeah... and it's not just us, others have the same problems.

I know :)... just limits the capabilities.

Do you guys know of any free software that allows me to overwrite the EDID of my TV? PowerStrip 3.9 does that but it costs ~$30...
This is the post that's probably the solution to my problem(if anybody else needs this):
DVI to HDMI on new 32LG5000 - no signal?

Custom Resolution Utility CRU used for over clocking monitors has something about extended EDID block and custom. Never looked into it as I did not have to to over clock. Maybe check that out. It is free.

Thanks for the recommendation. Tested that software, it doesn't have an option to write a new EDID to the TV. It doesn't work for me since I can't see the second display at all.

Fair enough. Sorry.

Actually it does not. The GPU's cant achieve that level of bandwidth to saturate the PCIe lane 8x or higher. But that discussion is for another day. :)

Ok, didn't know that. New thing I learned today. Thanks! :)

Hi guys. Same problem with GTX 660. After several unsuccessful attempts to get hdmi to work, I accidentally touched a wire near the GPU and the image appeared. In my case, there was a bad contact in the socket