I've got about 12 old white PC Engine, some of which are in horrible condition but I've yet to come across one that doesn't work. They are built like tanks.
I have. I originally bought two untested PCE + CD/interface unit sets. One had the original white PCE and the other one had the Core Grafx 1. The original white PCE didn't power up at all, and the CD drive that came with the other set had a bad motor. I ended up pairing the working Core Grafx with the working CD drive that came with the broken white PCE to make one working set. I don't really have the resources at my tiny place in Tokyo to try to repair this stuff, so I just sold the non-working stuff honestly as "non-working" on Yahoo auctions.
I love buying untested stuff and putting it to use though, so I'm going to get another untested white PCE. I've got a bid on one right now for 100 yen. It's mine!