Eggtimer Rocketry Eggtimer TRS Assembly Manual page 11

Note that some of the components are static sensitive, so you should avoid sources of static
electricity while you are handling them. We recommend that you assemble the Eggtimer TRS
on a wood or metal surface unless you are fortunate enough to have a high-temperature anti-
static mat (don't buy one just to build the Eggtimer TRS, however!) Avoid putting it on plastic
surfaces that generate static, and preferably put it together in a room that's not carpeted. That
being said, it's very unlikely that you will zap any of the components in the Eggtimer TRS
with static electricity, but consider yourself notified of the possibility...
Also note that some of the components are polarized, i.e. it matters which way you put them in.
If you solder one of these components in backwards, the effect will range from something not
lighting up (LEDs) to nothing at all working. It is CRITICAL that you test-fit the parts before
you solder, and that you make SURE that you have them pointed the right direction before
soldering. Like the old adage says, "Measure twice, cut once." If you solder a part onto the
board incorrectly, it can be a minor pain to remove if it only has two pins, or it can be virtually
impossible for something with a lot of pins. The Eggtimer TRS Limited Warranty does not
cover incorrect assembly, so if you mess up badly enough you may end up having to get
another kit and starting over; neither of us want that.
There are several different resistor values, so make sure you get the right ones in the right
place. They are marked on the boards, but once again you need to make SURE that you have
them in the right place before soldering. Unsoldering parts on a small circuit board like the
Eggtimer TRS isn't a lot of fun, even if you have a vacuum desoldering tool. Trust us, we've
been there before...
It is very important that you assemble the Eggtimer TRS in the order listed. This makes it
easier to access the surface-mount components, if you start soldering out of order it's going to
be tough for you to get to the pads of the SMT parts. Some of the instructions will call for you
to tack-tape parts to the board to maintain alignment while you solder, or to protect sensitive
areas from solder. You should ONLY use paper masking tape for that purpose, DO NOT use
"Scotch"® tape or electrical tape for this; plastic tapes can pick up static electricity and
damage parts, and electrical tape tends to leave a sticky residue.
Before you solder anything, make absolutely sure that you have the correct part and that it is
inserted in the board correctly. The board has all of the component values, outlines, and
polarities silk-screened on the top, so there shouldn't be any doubt about what goes where and
how. Nevertheless, if you have any questions about the assembly procedure, do not hesitate to
drop us a line at support@eggtimerrocketry.com before you solder the parts to the board. You
may have to wait a day for the answer, but it could save you a lot of grief later on!
The Eggtimer TRS Limited Warranty does not cover damage to parts while attempting to
desolder them because you inserted something incorrectly. We spent a lot of time making
sure that the assembly instructions were clear, but once again if you have any questions about
the assembly procedures drop us a line at support@eggtimerrockety.com before you solder.
In general, you are going to be soldering components from the inside of the board outwards.
This makes it easier to reach those itty bitty SMT pads than if you did it by component type
and had to keep going back and forth across the board. Most importantly with the SMT parts,