With tuners its usually the 6ghz npn transistor that goes. Its part number BFG94...
Here is the link i used to find the info (all in german but hey use translators)
Get a new Tuner Here: DBox2 Ersatztuner Nokia-Kabel - [email protected] - Shop
Ask your local TV repair man to install it for you
If any peeps need to source the transistor use google for the part number as there are some stockists in the UK.