In my day job, I work in I.T. Support. One unexpected solution to printer problems involves baking a circuit board in an oven.
a) HP Laserjet P2015 printer displays Paper Jam and Toner lights.
b) Intermittent problems then all status lights staying lit except for the Paper Jam light.
c) Various problems on other devices such as video cards and XBOX 360s have also been fixed this way. Google for "bake circuit board".
1. remove circuit board from device
2. preheat oven to 190ºC
3. remove any plastic cover tape from circuit board
4. cook the circuit board for 6 minutes
5. take it out and let it cool undisturbed
6. refit plastic cover tape
7. re-assemble device and test
N.B. This is not an exact science! Actual heat and bake times can vary, e.g.:
350ºF = 176.67ºC, 8 minutes
375ºF = 190.56ºC, 6 minutes
400ºF = 204.44ºC, 5 minutes
It is not clear which component benefits from the heat treatment. The visible solder on the surface does not melt, but there are several solder alloys which do melt at relatively low temperatures (see table at http://www.rfcafe.com/references/electrical/solder.htm).