yeah i got my 2500 used on ebay and it came with the q1 qlink like that.
what mine was doing was, let say i had the slider near the bottom and the pitch wqs real low, i could just barely touch the slider (like rock it just a bit to the side) and the pitch would jump to somewhere near the top of the range of the qlink, and it even recorded this way in the sequencer.
i called vst and ordered a new potentiometer (slider) and unsoldered the bad one off and popped the new one on, making sure to out a good well done glob of sauter err..sauder?? on the two middle anchor pins and everything was good to go after.
but two interesting things happened after;
1- i opened the bad slider and found out that it works by use of a loop (more like a U shape) of conductive wire that, as you move the slider down, the connecting point moves further away from the top of the "U" of wire, and this increases the resistance on the voltage moving through the U. (imagine a U wire with a dash though it...the dash being the bottom of the slider. the dash moves up and down the U)
what was causing it to jump values was simply, that the casing was loose and when i nudged the slider, it actually lifted the connector on the bottom of the slider off the U and it opened up the circuit, dropping the values assigned to the slider back to somewhere around 0-3
2- i found that the new slider i put on was of much better build quality and should not be as susceptible to the same issuse. BUT it has a horrible "feel" it was all scratchy and had no resistance, unlike the original slider that had a smooth feel and a bit of resistance when you move it.
so what i did was blast some wd40 in the new pot and after a few days when it set it a bit, i now have the choise of a traditionial 2500 slider (Q2) and a real quick moving flick back and forth dj style slider (the new Q1)
