I MAY have stripped my VTA tower, as turning the adjustment knob seems to make no difference. One of Mat's videos says "this can be fixed". Is that something I can do myself? Also, I have it (I think) at maximum height, but the cartridge (Sumiko Celebration II) BARELY clears the record with the tonearm lifter "up.". I have the unipivot needle as far down as it will go and still allow the tonearm to pivot. TT is a Rosewood Signature 21.