SamyGO

Did you really check your cable and get symbols you entered in terminal window?

For example - i have trouble with my ExLink - one day it stopped working. I figured out - my both com ports do not work. So i use usb2serial adapter and it works well.

Check connection settings - you could change connection speed to 57600 and watch what happens.

If your TV is under warranty - service should replace mainboard with new one. If not - you`ll pay for it...

As i said, desperate step with little chance for success - try shortening eeprom pins, might it helps... Your goal is any log on putty terminal...

Could i ask silly question ... Do you connect ExLink to "service" port?

Yes, it makes sense do not tell anything about patching/hacking...
Sure - same problem could be after firmware from samsung website.

What port is your "service" port? I see here 4 places to connect...

Sure. do not worry.
One more try: look at those contacts. If wires are going to cpu (not to tuner), you could shorten it, but if it leads to tuner, then leave it in peace

I have to go now, later i find the how to. It is here, on forum. You could search.

Read from here. But as i said - your problem is not related with service settings, but who knows...