HDMI output from desktop to HDTV doesn't work

Hi all,

I recently built a new desktop computer and I have encountered a problem where I can no longer connect the computer to my HDTV.

I have asked one or two forums so far on this issue, but unfortunately, no one has been able to come up with my solution. The symptoms of my problem are very strange. This post will be quite detailed and long so I will organise it a bit. If anyone could offer any help that would be great. Thanks.

Relevant Specifications

- CPU: Intel i5-2500K
- Motherboard: AsRock Z68M-USB3
- GPU: No discrete card, using Intel HD3000
- TV: Panasonic Viera 50" TH-P50S20A and also tested on Panasonic Viera 50" TH-50PX80, with same symptoms
- OS: Windows 7 Home Premium 64 bit

Summary of Problem

- For a few days after I built my new desktop, the HDMI port on the motherboard worked connecting my HDTV to display my computer. Both images and audio worked fine.
- Having not changed any software or hardware afterwards, or any settings on the computer or the TV, the HDTV no longer shows any signal, visual or audio when the computer is connected via HDMI.
- Windows 7 "Screen Resolution" and "Intel Graphics and Media Control Panel" are able to detect the HDTV and allow the changing of various settings, such as resolution, cloned desktop/single desktop/extended desktop and refresh rate, among others. The settings can be changed and are effectively implemented by the OS, but the TV shows no signal no matter what settings are chosen. (for example, if I choose extended desktop, my mouse can move off my primary display which is the monitor onto the HDTV, but there is no signal on the HDTV so nothing can be seen or heard on that side)

Steps I have performed in attempting to resolve the problem

- Changed and used two other HDMIs cable in case the first cable was broken --> No solution
- Tested the HDMI cable with my PS3 and laptop and Blu-Ray player to see if it was working --> The HDMI cable is working 100%
- Tested all three HDMI ports of my TV to check if they were working --> All were working with my other devices, none of them worked with the desktop
- Updated/uninstalled/rolled back Intel HD drivers --> No solution
- Used Windows System Restore to restore my configuration back to a date prior to the problem occuring --> No solution
- Reinstalled Windows 7 completely from the start and then installed drivers first thing --> No solution
- Tested whether the HDMI output on the motherboard was faulty by connecting my monitor using its HDMI port instead of the usual DVI-D --> Monitor worked fine visually, and could even output audio through a connected speaker, so both images and audio worked
- To see whether this was an isolated incident with the TV I connect to, I tried connecting to my other TV, an older Panasonic HDTV. The symptoms are the same. (Windows 7 and Intel software detects, but no visual or audio signal is shown)

Summary of My Diagnosis

As I have tried various steps in software and hardware, I am completely baffled at the moment. It seems my hardware should be fine and so should my software. It's just when it all comes together, it doesn't seem to work, as seen below.

Hardware:

- Motherboard/HDMI port: Tested to work fine with my monitor
- HDMI cable: Tested to work fine with multiple devices (laptop, PS3, Blu-Ray player)
- TV: Tested to work fine with multiple devices (laptop, PS3, Blu-Ray player)

Software:

- Intel drivers: Up to date, even tried older versions (also see below observation with my laptop)
- Windows 7: Restored to earlier system point and also tried reinstalled Windows completely after that didn't work

Further Strange and Puzzling Observations

- It suddenly stopped working, when it was working for a few days. I did not change any software or hardware. The fact that it worked initially indicates that there was no inherent incompatibility between the TV and my desktop.
- Windows 7 still detects the TV fine, and allows tinkering with its settings. It doesn't change the fact that no signal is dispalyed though.
- Both my TVs are affected, though both of them are Panasonics. My monitor however, is unaffected and works with HDMI.
- I have a laptop that has a Core i3-2357M processor and uses Intel HD3000 graphics as well. It can output to the TV absolutely fine over HDMI. I have compared the laptop with the desktop, and the drivers for Intel HD3000 are the exact same version. The driver for the TV, generic PnP monitor, is the same version as well.

Conclusion

Would anyone have any idea what is going on here? I'm very puzzled by the fact that everything should be fine, individually. Does anyone have other steps I could try?

My friend suggested that perhaps I could have a fault with the HDMI port that has stopped successful signals being sent to HDTVs, but not to monitors. But does such a fault even exist? Aren't HDMI signals all the same and it the way it works is the same regardless of whether the display is meant to be a TV or a monitor?

Also, has anyone ever heard of a motherboard fault/HDMI port fault where something could be detected but a successful signal could not be sent?

If you read through all of that, thank you, I know it was a long post.

Hi Tmg3,
I've EXACTLY the same problem with my HDTV (1080p) and Corei5 laptop (intel HD graphics card). I also went through all the steps mentioned above. I was searching the net for solution and found your post. Plz share if you have found out the solution. I'll be very grateful.
Regards
Durrani