SME 20/2 SME.V with hum and statics, and the left channel is drifting(sound on/of)

Czarivey, Thank you for a good advice! I will order new wire and give it a go:) And if i can't manage it I'l have to send it to SME for repair.

have a super weekend.

It's possible. 
There are 2 ways:
1. By pulling individual wire -- solder one end of new wire to either front or back of the old wire and another end respectively. "Circle" the new one into the tube
2. By pulling all at a time -- solder or better stick them together with crazy glue and pull them all at once till new wires stick out the arm tube.

you should try moving either all or individual wire before making decision which way is better -- certainly what comes out easier. Also decide which direction they go easier out or in...
In most cases you don't have to disassemble "tifany" to pull wires out

Thank you czarivey. Cartridge clips has also been canged, I have tried diferent cables, so it should not be clips or rca. So yes, i also think it is the internal wire, properbly in the "tiffany" connection in the arm. I tried to move/rotate the "tiffany" connection on the arm when the left chanel was "drifting" yesterday, and then the channel comes back. Do anyone know if it is possible to change the internal wire in a SME.V by yourself?

You can look up the RCA termination if loose. Check also cartridge clips if they have any loose connection to the arm wires. Otherwise, the arm may have internal wires issues.
The internal wire damage is usually done within moving parts of the arm which may also mean that there might be either incorrect assembly from the brand new or structural damage or defect.