Thanks Florian for your response.
I have to admit that you method is pretty hardcore! Personally I am afraid to do that - I might fry something in the process and there is way to many "points of interest" to check...maybe I will put the card it a sock or something..
What bothers me is that I can't find any topic on the subject (radically heat affected tuning). I suspect the transposition circuit (a FET or transistor going bad).
pyjamagroove