Eggtimer Rocketry Eggtimer TRS Assembly Manual page 19

__ Similarly, solder the LOWER optoisolator into place.
__ Locate the two 10K 0805 SMT resistors immediately to the right of the optoisolators,
they will be marked "103" on the board. There are actually a group of four of them, but we are
only concerned with the two immediately next to them optoisolators right now.
__ Using only a tiny bit of solder, tin ONE pad of the UPPER of the two 10K resistors.
Remove ONE 10K resistor (marked "103") from the carrier tape.
__
__ With the tweezers, gently place the 10K resistor onto the pads. Holding the soldering
iron in your other hand, gently heat up the resistor lead above the tinned pad until the solder
flows, hold the heat for another 2-3 seconds, then remove the iron. Hold the part in place for at
least 5 seconds to allow the solder to cool.
__ Using only a tiny amount of solder, solder the other pad into place. You may want to
use a very small piece of PAPER masking tape to hold the resistor in place so that it won't
come off the board in case you overheat it a little and heat transfers to the other pad. (Trust us,
this happens...)
With a 10x jeweler's loupe, inspect the solder joints. Redress as necessary.
__
__ Similarly, solder the LOWER of the two 10K resistors.