Hardware & Technical RX 480 suddenly not displaying on TV

[kizcat]

I've hit the limit on my trouble shooting knowledge and really need help with this one.

The brief outline leading up today is as follows:

Since building my computer last November-ish, I have only ever had it connected to a TV, and up until the last couple of weeks it has worked pretty well, the only notable problem being that if I didn't turn my TV on before the computer I would end up with strange colour distortions towards the purple spectrum instead of normal colouring, but a restart always solved that.

The only changes to my configuration that have happened are within this last couple of weeks. I have had to change the HDMI cable, I am now using a 1.4 5m HDMI cable. (previously I was using a 1.5m cable but I don't know any more about it than that other than it may or may not have been from a PS4 - the cable wasn't mine)
The immediate changes to the new cable resulted in an occasional screen flicking to black once every 10 to 15 minutes lasting for about 2-5 seconds. But it appears to have suddenly gotten worse the last couple of days displaying a 'static' like image similar to when tuning an old analogue TV. and today it flickered and now nothing.

The only other changes have been a recent windows 10 update (that it just downloaded and installed of its own accord) and AMD graphics driver updates which I do regularly. Both of these changes have been rolled back and i've even done a system restore to 5 days ago when I was having no issues.

Things I have tried:

Rolling back update and system restore as above.

I have tried 2 other 1m HDMI cables and am getting no output on my TV on the 1m ones at all, and on the 5m one I get the BIOS splash screen just after turning the computer on (although with none of the options to press F2 for BIOS and F11 etc like it would normally tell me along the bottom) and then no signal at all.

Checked inside. All the cables are still connected correctly inside, nothing is loose, everything even sounds normal, no hotter than normal.

Unplugged everything except keyboard and mouse incase it was a power draw issue, which changed nothing.

I'm sure it isn't the graphics card as I have the computer specifically for VR, and after letting it boot up and run, even without a desktop display on the TV, the Oculus home interface works fine from within the headset.

I'm also sure it isn't the TV as I've tried all the cables on an Xbox One and have no issues with display from it.

I've deleted and reinstalled all the AMD crimson and drivers, no changes.

I use a DVI to HDMI adaptor between the computer and TV normally so the VR headset can use the HDMI out on the GPU. I have used all 3 HDMI cables via the adaptor and the GPUs HDMI out and it was made no different. no signal output to the TV.

The other thing I have tried is plugging the computer in to a different TV. (an older small one I was contemplating on throwing away). DVI to HDMI and HDMI to HDMI, all 3 cables, it displays fine on this other TV, no flickering or anything.

So I am absolutely stumped here.

Out of curiosity I plugged my main TV in as well, and tried to set it up as a second monitor/clone/extend (what ever option it would let me try), and the computer detects it's there, but doesn't seem to be able to display anything on it.

Has anyone got any ideas what might have happened or what I can do to fix this? Any help/suggestions would be appreciated!

TL;DR

Spoiler

No issues for months, use TV as monitor normally, changed HDMI cable 2 weeks ago, started getting flickering lasting 2-5 seconds every 10-15mins. Suddenly getting static like issues (similar to old tvs being tuned on analogue).
Today it was working fine, had a flicker, and then suddenly no signal.
Tried 3 different HDMI cables with no signal.
Everything plugged in properly and connected.
Still getting output from GPU to VR headset with no issues.
Rolled back and reinstalled drivers.
Unplugged everything except keyboard and mouse to rule out power issues.
Plugged into different older smaller tv and it's working fine with no flickering or issues.
Original TV is recognised by computer when plugged in as second display but still shows out signal/output.
Am stumped. help please

Spec: (nothing has been overclocked)
CPU: i5 6600k 3.5GHz
GPU: AMD RX 480 8GB
RAM: 2x 8GB DDR4 (cant remember the clock)
SSD 500gb
PSU: VS 550
MB: MSI Z170A PC MATE

 

[CMDR MAIN SEQUENCE]

How many HDMI inputs does the TV have? When you say you have tried an Xbox on the TV was it with the same HDMI port (as the computer)?

Tried a "restore factory defaults" on the TV?

 

[Shadowdancer]

I wouldn't rule out a slight defect on the graphics card, it's possible that some timing or filter circuit degraded to the point where it can communicate with some devices but not with others. The progressing nature you describe would agree with that.

Did you try attaching the TVs it doesn't work with and run them at (very) low resolutions?

 

[kizcat]

How many HDMI inputs does the TV have? When you say you have tried an Xbox on the TV was it with the same HDMI port (as the computer)?

Tried a "restore factory defaults" on the TV?

I wouldn't rule out a slight defect on the graphics card, it's possible that some timing circuit degraded to the point where it can communicate with some devices but not with others. The progressing nature you describe would agree with that.

Did you try attaching the TVs it doesn't work with and run them at (very) low resolutions?

The TV has 2 HDMI ports. HDMI1 (which is also an ARC port) and HDMI2.

The computer has always been in HDMI2. I have tried the xbox in the HDMI 2 port, and was getting a really low resolution through it, 640x480. Which the xbox auto-detected as correct. Changing it manually I was able to get 1080p with no issues for the xbox. (but still nothing on the computer)

I've plugged the computer into the HMDI1 ARC port and which the 5m HDMI cable it seems to be working now, at 1080, so far no flickers or anything (although its only been a couple of minutes)...... literally as i was typing that, flicker with static followed by flicker and back to normal. It wont display anything from the shorter cables.

On the smaller TV it was running at 1080 with no issues at all. It just seems to really not like the original TV now for some reason. I have just lowered the resolution to 1360x768, still nothing on HDMI2, just waiting to see if the flickering/static happens again on HDMI1 with the reduced resolution

I haven't tried the factory defaults on the TV yet, that will probably be my next step

 

[Shadowdancer]

I've plugged the computer into the HMDI1 ARC port and which the 5m HDMI cable it seems to be working now, at 1080, so far no flickers or anything (although its only been a couple of minutes)...... literally as i was typing that, flicker with static followed by flicker and back to normal. It wont display anything from the shorter cables.

Sounds like a bad component (99.9% it's a capacitor) that heats up and fails to meet specifications. If the card is still under warranty, use that.

 

[kizcat]

That's a shame, and frustrating. It went out of warranty about 2 months ago I think >.>
Still getting the flickering at a lower resolution, just not as significantly.

I don't get why it will work on 1 HDMI port and not the other suddenly though.

 

[shadragon]

I lost HDMI video from my Entertainment NAS. The box worked fine, but no video. We assumed it was a lightning strike. The NAS was on a UPS, but the cable system wasn't.

It is now.

 

[The Chairmaker]

Depending on manufacturer and country some rx480s have i believe 2 year warranties.

 

[kizcat]

I lost HDMI video from my Entertainment NAS. The box worked fine, but no video. We assumed it was a lightning strike. The NAS was on a UPS, but the cable system wasn't.

It is now.

Hmm... I might have to consider a surge protector of some kind I think.

I happened to notice, just out of pure luck because it was so quiet at the time, that when anything kicks in elsewhere in my flat, fridge or freezer, even the boiler, is when I get the sudden flicker. So I am now wondering whether it's a power draw issue. Just strange it's only started happening since changing to a longer HDMI cable (5m from ~2m). and strange that the two 1m ones give no output at all.

None of my other devices are affected at all.

(although I haven't ruled out graphics card issues as mentioned by people above)


Edit:
Although to add to the problem, the TV has auto changed it's resolution on both my HDMI channels to 640x480, which mean beyond the initial splash screen I now cant get anything from my computer on either channel. and there seems to be no way to manually change it (i've also factory reset the TV but it didn't seem to help)

So could it be the the PC has auto detected the TV and force changed the resolution during one of these 'flickers' and basically got itself stuck there?

(As a side note it displays absolutely fine on my other TV - no flickers when other devices turn on, it's fine)