hooked up TT and preamp to receiver sound fades out after 4-5 seconds


I just bought a realistic lab 400 turntable and hooked it up to my receiver a pioneer vsx 56txi into the phono input. I will add that I am a total newbie to this. I got nothing no sound at all. I researched and bought a phono preamp behringer PP400. I hooked it into the phono in on the audio of the receiver and connected the ground wire and had sound for about 4-5 seconds and than no sound. I tried connecting to the cd audio in and same thing only sound for about 4-5 seconds. Everything else works fine regarding sound. Stumped. I would appreciate any suggestions you might have.
atrust
Exactly! noromance is correct, once you purchased a external phono pre amp you need to use one of the normal line level inputs like...CD or AUX or Tuner or just about any input will work as long as its not the internal phono. 
The OP states that he tried hooking it up to the CD input, but the same thing happens.

I looked at that receiver.  My lord does that have a bunch of crap on it.  Most AV receivers need to be set up right from the beginning to work with non surround/video sources.

IMHO, there is something in the receiver's vast menu, not set up correctly.