MacBook suddenly won't detect my TV anymore - already tried anything

Hello everyone,

I hope I can find help here... I couldn't find any in Apple Stores...

_+*If you don't want to read the long text, there are some cliff notes below*+_

I have a problem with my 42" Toshiba LCD TV.

Here's my setup:

MacBook 13" Unibody with 4GB RAM, Snow Leopard 10.6.4 and all the latest updates.

I used to use it as my movie display, only plugging it in when watching a movie etc... For work I am using a Dell 2209WA, which is still working perfectly with exactly the same cable configuration.

My connection should be standard and looks like this:

1. Mini-Display Port to DVI
2. DVI-to-HDMI-cable
3. Plugged in into my TV

Some day, I decided to watch a movie, plugged of the Dell and plugged in the Toshiba TV. No signal, my MacBook didn't even detect any external display.

I searched up the internet, and found that there were problems with the update 10.6.2, and after 10.6.3 seemed to work for most of the persons concerned, 10.6.4 seemed to mess it up once more.

Fortunately I am running time machine, so I started to restore older OS X versions, starting with 10.5.8 and going the way all up to 10.6.4 again. It just wouldn't work. So I formatted my MacBook and made a fresh install of Mac OS Snow Leopard, again starting with every single update step. But nothing worked, so I restored my latest 10.6.4 backup.

I went to a friend's house and connected my MacBook with the same cables to his TV, and it worked perfectly. I then visited an Apple Store, describing my problem and connecting it to their TV - it worked. I was like... come on!!!

Nevertheless I bought a new MiniDisplay-Port-to-DVI-Adapter I could bring back any time, just to test it. I even bought new cables. Nothing helped.

I then started to reset PRAM, and CMS. I moved stored display profiles to trash, restarting and hoping it would work, but nothing...

Any time I connect the DisplayPort, my MacBook screen blinks, as it should, but does not recognize any display. I tried SwitchResX, nothing as well.

_+*Here are the Cliffnotes of what I've done and what's going on:*+_

MacBook won't recognize/detect Toshiba TV
MacBook recognizes/detects Dell TFT with same cable configuration
MacBook works fine with other TVs
I changed cables
I changed HDMI ports
I tried another adapter (DisplayPort)
PRAM and SCM reset without success
Deleting display profiles without success
I tried every Snow Leopard Release from 10.5.8 to 10.6.4
SwitchResX did not work
I restored my TV's standard configuration, and turned any auto image adjustion off
checked whether MacBook is concerned by nvidia callback - negative
It seems that there is either a problem with my television or with my driver's/software's configuration on the MacBook. Maybe it is sending a signal/resolution that cannot be displayed, but why should it?

If it does, it would have to detect the TV first I guess... A fact that brings me to the point that it might be the TV and not the MacBook is that it didn't even work with a fresh installed SL, so there were definately no wrong display profiles saved and applied.
I don't know what to do, is there anyone who can help me? Any advice is greatly appreciated!

Regards from Germany

dohdoh