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

@mofimadness That's what makes this board great. Amidst the sturm und drang and other noise, these thoughtful, methodical solutions and thoughts still surface.

Yes thank you mofimadness. I did all that you said at the beginning. I tried phono first , than changed it to line. The same result. Than I went to cd and did the same thing, same results. That is why I am pulling my hair out. That is when I posted here and walked away from it for the day before I end up with a flying TT. Thank you for your responses. I will start over and try again sometime today.

Try removing the headshell, checking to be sure there is no dirt or grim built up inside the connector, (on both the tonearm and the headshell itself), then reinstall it. Check to be sure the stylus assembly is firmly mounted into the cartridge body. Might not be all the way in and is causing a disconnect.

Also, try to start the cartridge a few tracks inside the LP. You might have a break in the tonearm wires that starts almost right at the beginning of the record.

Is there another system you could try the turntable out on?  We need to eliminate each piece, a piece at a time to see where the problem is.

Well I set it up again like I did before and same thing. So I just started turning things on in different orders and it turned something on. I am getting sound now and it stays on. The only problem is it only comes from the rear 2 speakers and not the 2 front and center speakers. But at least I have sound and less hair. Thanks for all your suggestions which were all correct user error I guess or just luck. Thank goodness because this TT was almost going to have to grow wings to survive. Enjoy you day.

Seems like you have an issue with the set-up of the AVR.  I would do a hard re-set and work from scratch.