Well, I've got the soldering iron out again. The Panasonic DVR died last night, and the Internets told me that it was caused not by DW pushing the wrong buttons, but by the failure of two capacitors (as seen here
They were indeed bad, and I've removed them. Yay for the Internets!
Here are my questions:
1. Should I do any cleaning of the connection on the board before soldering in the new caps?
2. Should I invest in a better soldering iron than this 40 W model?