OK, so no power at the floppy port, no change with fresh solder. Time to start testing on the analog board itself, see if voltages are present where they need to be, starting from the switch and working forward. I'm currently getting ready to leave town for the week, so I can't go in to detail myself, but perhaps someone else can?
It might be worth watching this:
. and this:
in which Bruce does some analog board repair
Also, get familiar with chapter six of Pina's Repair Secrets, where he walks through power / analog related issues in detail.
Ultimately - take heart! These analog boards are pretty much always repairable, and the process is fun and addictive.