I bought a Shimano 105 front derailleur (FD5600) from a local guy on eBay for $19. It came off a 2007 Cannondale. I saved shipping by picking it up. I installed it on my 17 year old Trek 1000. But the chain would rub in the inside of the cage when the chain line turned this way or that. I adjusted it the best i could.
Then it occurred to me that the 2007 Cannondale likely had a 10 speed cassette on the back and a narrower chain. That my fat 7 speed chain was just too fat for this derailleur. I did a search on Google, and sure enough, the FD5600 is apparently designed for a 10 speed chain. If I want a Shimano 105 front derailluer, I think I want the FD1050. So I will keep an eye out on eBay for one.
So int he mean time, I removed the Shimano 105 front derailleur and reinstalled the Suntour Blaze derailleur which is original to the bike. The shift cable is just barely long enough, so I will probably replace that tonight with a fresh cable.