The Liminal Build Guide SMD – (Pt. 1 of 4)


Part 1.0 – SMD

SMD Diodes
(ft. Smol Parts)


1.1 | Tools and Stuff

A hobbyist should, and probably already does, have these basic tools in their fanny-pack of wonders. But These are the ones I recommend and use daily.

  1. A Good Temperature-Controlled Soldering Iron
    • The Hakko FX-888D is the hobbyist standard for many and has been the single best choice for some time now. Smart design, good construction, underrated colorway.
  2. Solder Wire
    • My Newest Favorite Being an Absolute Unit of Kester 60/40 .5mm ID Wire recommended by most of the 40% Discord. This roll is enough to last most people a lifetime.
  3. Tweezer
    • Literally any tweezers. Ceramic, Steel, Copper, Wood, Anything (okay not plastic).

1.2 | Polarity of SMD Diodes

20/20 vision recommended

SMD Diodes (and all other switching diodes) do have a correct orientation (polarity). As such, they need to be soldering in the correct direction in order to function as intended.

Have a look at the images below. Take note of the sides of the diodes, and where they need to be positioned on the PCB.

Take a look at your prepared diodes and make sure you understand how they are seated correctly.

SOME DIODE LOCATIONS ON PCB ARE ORIENTED DIFFERENTLY
THAN THE REST.

DOUBLE CHECK ALL POSITIONS TO MAKE SURE ALL
SQUARE HOLES ON PCB ARE LINED UP TO BARRED-LINES ON DIDOES.


1.3 | Seating/Soldering SMD Diodes

Once again, there are a number of ways people prefer to set and soldering SMD PCB components. In this guide I will be showing you my personal method.

A.) First get a diode set and positioned in your tweezers’s mighty grip. Getting this ready before touching your iron to anything will make your life a whole lot easier.


B.) Diode in position, take your Soldering Iron, heated to 380-410°C, and touch the tip to one of the pads on the PCB. Hold this for 2-4sec. to allow for the solder to visually melt and be “flow-able”.

(The PCBs come with solder paste pre-applied to the surface. You wont need to lead any solder wire yourself just to seat the SMD Diodes in place)


C.) As soon as the solder on the pad has heated up and is free to wiggle around a bit, take your diode and slide it into place on the pad. The foot of the diode will look like it has “attracted” some solder and the paste should flow around the foot a small bit.

(The foot of the diode will be roughly center with the pad on the PCB)

Lift your iron off the solder as soon as the diode is in place and hold the diode there for 2-3sec while the solder re-sets and becomes solid again.

(Don’t blow the solder as it cools, this can introduce moisture into the contact points.)


D.) Turn yourself (or PCB) around and get a good look at the rear side of the seated diodes (anode end)

This side is a little different as since the other side has been seated at a certain height, you might need a little more solder to get a solid connection between the foot of the diode and the PCB.


E.) Same process as before but this time after heating up the paste on the PCB and visually seeing the solder melt and flow, take a bit of wire solder and lead it into the foot/pad area.

A very small amount is needed. Just enough to grab that foot and bridge it down to the pad below (Don’t commit the dreaded “solder-glob” sin of the hobbyist keyboard builder)

Be confident in doing this. You have extra diodes if you mess up. Hold, Lead, Bridge, Let-Go.

AND REPEAT!

Note: There are 52 Total Diode Positions*
*There is an 87% chance you will miss one or forget to solder one and not notice till you get your entire build done, all the while wondering why its not working.


1.4 | Snack Break

This is the part where you go wash your hands and say hello to your fellow friendly neighbor from a comfortable 4meter distance. After you engage in some extremely uncomfortable eye-contact, shut your door as slow as physically possible and wash your hands again. Then go grab hand-full of baby carrots and a case of some nice cold Capri-Sun.

Enjoy yourself. You are an extraordinary individual.