Need advice. "sparks" or "clicks" on vir

[mousehead2]

Hello anyone and everyone,
I just bought a used c on ebay. The seller claimed it was "absolute mint" but I'm not sure. On certain patches (in particular, patch E60 marimba1zs) as I play a chord for awhile (15, 20, 40 seconds) I start to hear "sparky" sounds - the same sound one gets when changing patches while the previous one is still fading. I know this topic was dealt with before but that was quite awhile ago and the OS has changed since then.
I tried "everything":
-Increasing the attack and decay envelope times on both envelopes
-decreasing the release times
-unassigning all Lfos and mods
-turning off all effects and reverb/delay
-decreasing osc volume, patch volume, and main volume
-routing audio out of out 2
-unison is off already
I was able to produce the same effect on a unit at the local music store, but their unit seemed a little beat up and buggy anyway, so I'm not sure what that means either. The funny thing is that while I don't feel that I can cause it, once it DOES start, it feels that I can "catch" it (cause it to happen) the way one can "catch" the echos from a delay (play directly on top of them) or "catch" a Lfo's phase. In other words, I feel that I can help it to keep happening... It only happens on a handful of patches and usually takes some time to kick in. But once it starts, it seems to happen more easily, sometimes with the first chord.
Does anyone find this to happens also? Can anyone out there also cause it (for E60 marimba1zs especially)? Is it normal for Virus? Or should I venture to return the unit? Any advice would be helpful. Sorry this is so long, but thanks. By the way, I'm listening with headphones...
Mousehead