Now it's time to work on the yellow LED. We'll need two female/female jumper cables, one 220ohm resistor and our 5mm super bright yellow LED.
Secure the LED to a pair of helping third hands. Trim the legs short and apply solder to tin them. The longer leg is postiive, shorter is negative. The bigger metal piece inside the LED diffuser indicates positive polarity.
Prep Jumper Cables
We'll need to prep the two jumper cables just like we did for the PowerBoost 1000C. Remove the plastic connectors using a hobby knife, exposing the metal contacts.
Slip on a piece of heat shrink over the exposed contact and carefully bend the connector so its right-angled. Appy heat to shrink and insulate the exposed metal. You'll need to do this to both wires but only one end.
Connect Jumper Cables to LED
Slip on another piece of heat shrink to the other end of the jumper cable. The straight jumper contacts can be inserted to the shorted legs of the LEDs. Appy a bit of solder to secure the wires, then apply heat to insulate the exposed connections.
Cut the ground wire and remove a bit of insulation for each half. Tin the two wires and shorten the legs of the resistor.
Add a piece of heat shrink to one of the ground wire halves.
Tin the shortened legs of the resistor and solder the resistor inline with the two ground wires.
Slip the piece of heat shrink over the resistor and appy heat to insulate the exposed wire and resistor.
With the resistor added and exposed connections insulated, it's a good idea to test the LED using a coincell battery. Place the positive wire over the positive side of the battery and negative over negative. The LED should instantly light up.
Install LED diffuser
Insert the LED ring over the LED diffuser cap. If it doesn't fit, you'll need to use a filing tool or hobby knife to loosen the tolerances. Then, insert the LED diffuser over the LED - it should press fit and stay in place. If not, use filing tool or hobby knife. If it doesn't stay in place, use glue to secure them together.