Patches and discussion for Ensoniq VFX family

I know that there is a lot of info on the web (and I am looking) but I have a somewhat time-sensitive situation, so I am asking for any thoughts or opinions to help save time.

After years of wanting, I finally got a VFX (it's an SD-II model). I got it off ebay, from a long time seller with 100% positive feedback. The price was fair and the unit came as pictured, reasonably well packed.

The synth starts up fine and appears to work normally in all regards except for an issue with the keys.

The AFTERTOUCH is *very* spotty. It in all cases, it requires quite a bit of pressure but, even then, some keys send a full pressure response, some keys send none at all, some keys send less than the full range but are consistent, while some keys fluctuate (sending pressure sometimes but not other times).

What I an hoping to hear is whether or not any of you folks think this is something that can be dealt with or not. If it can be dealt with, I'm not in a hurry. I won't mind if I'll need to do research and/or order some old parts if they're available, or even buy a second vfx as a parts machine. I'm willing to take it on as a project, as I bought this just for my own use and pleasure.

The time sensitive part is that I just received this and I really need to figure out whether or not to wrestle with it or tell the seller I want to send it back. Like I said, he seems like a good guy and I don't want to take him to task or blast him with negative feedback, but I also don't want to take a week to figure out whether or not I'll keep the thing and _then_ ask him for a refund.

PS - another much smaller issue (that I can deal with if necessary) is that one key (C#5) won't trigger any sound on any patch unless it's played quite hard. But the *main* issue is the aftertouch.

I'm open to and grateful for ANY AND ALL opinions.

Thanks and kind regards, Scott