My RCA out are working but the main volume knob has a problem, it crackle when moved and mute the output until I tweak with it and push it around gently. Works for some minutes and then again....

Anyone got the same problem before ?
Is it necessary to change the knob part with a spare original or maybe some soldering would be good ?

pots ('knob') do wear out over time - because it is crackly this is what I would guess has happened..

If you can figure out what the resistance value of the potentiometer is (usually written on the side of the component) you could get one from an electronic components store.. then swapping is simply a matter of unsoldering the old one and putting the new one in.. If you know what you're doing it's easy.. if you dont unfortunately you'd have to pay for it - and probably get charged a ridiculous price.

thanks man I gave a look at the inside but dropped the idea of doing it by myself... at least for now i'll keep tweaking it to make it sound....thanks again

Seems like a problem amongst SPs.. I have the same problem with my 202. My headphone jack on the 202 was dislodged and was repaired by a tech for $60. Unfortunately, when I got it back I only noticed the RCA problem after I had already reached my apartment.