I'd recomend doing what I did. I got a good condition 4000 from EBay. Had very little battery issues but a bad Par: port and, after a few months the sound started going. I'd added a CD drive and max memory so I wanted to preserve the system.
I sent it over to JJ at AmigaCenter.com in France. Had the bad sound and par: port fixed, added a rechargeable battery, and generally reconditioned the board. I had additional issues with my processor card which were also cured. Highly recommend his service! He put up with quite a few questions from me and guided me when I needed it after the repair.
The downside, from Elk Grove, to your north, the shipping to desination times were on order of 2-3 weeks by international mail.
Good luck on your hunt!
Bob
