Section 4 - The Processor Side - Eggtimer Rocketry Eggtimer TRS Assembly Manual

Remove the SN74HC02 from it's package. Note that there is a notch, dot, or bar marked on
one end, this should be facing UP. With tweezers, hold the SN74HC02 in place, making sure
it's centered on the pads. If you have trouble with this, you can cut an 1/8" wide strip of paper
masking tape and use it to hold the part to the board while you solder. Holding the soldering
iron in your other hand, heat up the lead on the pad that you tinned, hold the iron for 5 seconds
after the solder flows then remove the iron. Wait at least 10 seconds before releasing the
tweezers to give the solder a chance to cool.
With a 10x jeweler's loupe, inspect the solder pads to make sure that the leads are centered on
the pads. If they are not, reheat the solder joint and move the part into place.
When you are satisfied with the alignment, solder the other leads to the pads. Skip over pads
and alternate sides to help prevent solder bridges, and allow at least 10 seconds between each
solder joint to allow the part to cool.
With the 10x jeweler's loupe, inspect all of the solder joints to make sure that they are nice
and shiny, cover the pad and the lead, and that there are no bridges. Reheat/resolder as
necessary, and use solder wick to clean up any bridges.
Section 4 – The Processor Side
Looking at the bottom of the board, you can see the spot for the processor, it's a long 28-pin
part with the notch on the left side. You will also see that there are a number of SMT
components sitting right smack dab in the middle of it. These parts are installed first, then after
the board is tested the actual processor is installed. Because you cannot acces s these parts