last night i wanted to watch Alien, after i inserted the disc into the player (CLD-S315) he showed me NO SOUND.
I have the audio channels switched through, but there was no sound!
does anyone have an idea?

What player are you using? Some PAL players does not have support for analog audio. For some reason they removed the circuit/support because digital audio were the new thing. Try a PAL disc that has digital audio and another one with analog audio to confirm this.

EDIT: I see now that you have a Pioneer CLD-S315. If you see in this link, you can see that it only has analog sound for NTSC discs.

Thank you for your quick response

If you want a PAL LaserDisc player that will play pretty much anything you throw at it (with the exception of oddities like the Japanese high-definition titles that were produced right at the end of LaserDisc's life), I'd recommend the CLD-D925. It's reasonably good at picture (with a few issues shared by most similar Pioneer players — I'd certainly expect it to be no worse than the one you have), has automatic side changing (so half the amount of getting up to change the disc), and plays PAL and NTSC discs with both analogue and digital audio. Many would argue it's the best player that the PAL regions ever got, and so if you can find it in Germany for a reasonable price (I don't know what shipping costs would add...), I'd go for it.

Ditto that

I use a CLD-2950 for PAL discs, which is also a really nice player. I think most later released players got analog support back. Guess Pioneer realized it was stupid to remove.

I have a DVL-919E for PAL playback. It also plays all audio formats.