So, i first lifted up one leg of the D5, D3, D6 and the picture was still dim.
Then i continued to lift up one leg of D4, D1 and D2 and behold, the picture is way brighter than it was before!
Though, there's still some kind of problem with that video card. I got another LCD monitor (SyncMaster 213T), and only with this video card, it is blinking - has picture for about half a second and then goes to search for input again. The monitor works correctly with other videocards and computers. So it seems like what ever this new monitor is using to detect the signal, that signal is still weak...
But the good news is, the brightness itself is good now. So need to replace those diodes. (Y)
EDIT: I've changed the lcd to not auto-switch input, but the picture is still getting lost constantly. Looks like the screen is loosing sync or whatever is needed to display the picture and from it i assume, some signal is still too weak.
I also just went through the black and white marked lines once more on the card, as they were marked in a picture in this thread, and they look healthy at every testpoint.
"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!