connection problem with an Cherry 3700 Numpad

[Phenix]

Hello

Just purchased an Cherry 3700 HAD Numpad and Im wondering why I have problems.
line: Numpad->Adapter->PS2 Adapter->USB PC

sometimes it gets connected for ~30 seconds (then I am able to type numbers.., but quite often nothing happens. In another case just Enter worked).

The one I got has ghetto greens installed, Numlock LED doesn't work (so far).

Is this problem caused because I have no board plugged in in the socket? (wiki says that there may be problems)

[kbdfr]

[…] Is this problem caused because I have no board plugged in in the socket? (wiki says that there may be problems)

No. The problem is caused by bad modding to ghetto greens, affecting both the "5" key and the "Esc" key.
In addition, the "Enter" key stabilizer is installed the wrong way round.

Well, this obviously is a completely nonsensical answer
but do you really expect an answer? After all,
- as you yourself write, "wiki says that there may be problems" when no board is connected to the socket, and
- you can easily find out yourself by… just plugging a board into the socket.

[Phenix]

If i had an board with that connector I would have tried.

[kbdfr]

But you are the only one with that specific numpad.
The only answer you can possibly get is "perhaps" - which you already know from the wiki.