[Radioactive]

Scratching my head on "heating the circuit board". I build a lot of my audio components and have never heard of this. Heat and circuit boards are not friends.

Repaired the inner led couple of weeks ago. Found which resistor was the problem by hooking up the tail light assembly and pushing on each component to find the open circuit. Used a plastic soldering tool to hold the smd resistor in place while hitting the ends long enough to re-melt present solder. No flux or additional solder. Holding the iron on the solder pad too long can damage board and/or resistor.

Edit- I stand somewhat corrected on heating board. Try to avoid SMD if I can. There is technique of heating the whole pcb for "mass" soldering of SMD components. I would be careful using this to resolder just a small number. You risk disturbing other components or over heating the board if not done correctly.