HELP ! Noise Issue - DUAL CS 455-1

Hi Guys, 

I just plugged back my old dual cs 455-1 after fews years of being stock in a box and a very unpleasant noise (like strong grounding noise) appears.  

When I touch one the rca it makes a very high pitch sound too. 

I tried the following things but with nothing better: 
- record player on or off: same noise 
- cartridge on or removed from the arm: same noise 
- I removed the stock rca cable and card and replaced them by brand new RCA socket and new ground cable: same noise 
- If I unplug the ground cable from the amp or if I let it connected on the amp: no change 

I am wondering if it would be possible that the ground cable is not properly attached where it should be on the player. 

Where should it be attached exactly (beside that on the little screw on the card and chassis)? 

Would you have any idea of what the problem could be? 

I spent two days trying to identify the problem with no success, I am desperate now  

Thanks in advance