Thanks for your answer! What pins do you mean? I reopened my beomaster and can't seem to findthe pins you mean. I can't really figure out where these copper things connect?

When you remove the panel with the copper tabs, look carefully on the electronic board at the place where the tabs would go if it would be in it's place. You will see small metal pins, about 1 centimeter in lenght that goes up from the electronic board. There's one pin for each function. The copper tab HAS to sit on them for the sensi-touch to function properly. Try to touch these pins (only those pins...) with a finger: You body act as an antenna and send a signal to activate the related functions. If it works, then it's just that the copper tabs don't touch these pins properly when close... It's tricky to put the front panel properly, but when you will locate these pins, it will be much easier for you...

Thanks again! Indeed it is tricky to put the front panel back, I can't fit it in properly. Dothe copper things have to tocuh the pins with the back (straight) of the tip in the front (v-shaped)?

Sorry to go in such detail, but I can't get it to work at the moment. Thanks in advance!

Update! I managed to get the copper things connected to the pins, they were bent in the wrong direction. 

However, then the next problem shows up. When I assemble the unit the volume controles work fine. But on the right side it stays at "fm5". All the copper things are perfectly aligned, so they must tocuh the pins as well. When I push another button ("tape" for example) it switches to that channel but immediately switches back to fm5, as if that one is always triggered. Thorough cleaning and some sanding doesn't help. When dissassembled, it switches perfectly between channels when I touch the pins on the board.

Any suggestions? Thanks!

Thans Martin. But if the problem world be in the lamps or the transistors, wouldn't it be weird that everything is working perfectly when the sensi-touch is not connected, i.e. when I touch the pins on the board? That is what made me think there was sommering else wrong?

Yes, but your fingers used directly on the pins will give a completely different (and much stronger) signal.
But check those bronze forks again. They will have to grip their respective pin with their forks and with a little
tension too.

Martin