Soldering the Cube to the PCB
Place the LED cube on the top side of the PCB with the correct
orientation as shown in Figure 36. The uncut common layer anode
leads should be facing the side of the board where the transistors are
mounted. (See the edge of the PCB with four pads named L0, L1, L2,
L3.) There will now be 16 pads named PD0 to PD7 and PB0 to PB7
for connection of the common cathode lines.
The 16 common cathode leads of the cube should be inserted
into these pads using narrow tweezers. It would be helpful to tilt the
cube a little and then insert the four common cathode leads by row.
See a close-up in Figure 37.
Try to keep a distance of 1/2” between the PCB and the LEDs to
avoid unwanted short circuits between the cube connections and
PCB pads. Make sure the cube is symmetrically placed on the PCB.
Now — with the exception of the pins PB7, PD2, and PD1 — the
common cathode leads can be soldered on the bottom side. You will
need to hold the cube PCB upside down to solder the common
cathode pins on the bottom of it (see Figure 38).
Trim the excess wire from the soldered common cathode
leads leaving a tiny portion from the roots, and then solder the
pins. Solder PB7, PD1, and PD2 from the top side of the PCB.
On the bottom side, cut PB7 flush to the PCB, and the PD1 and
PD2 leads as short as you can.
Place the P1 DC barrel jack on the bottom side. Since PB7
pin overlaps the P1 jack, it is necessary that PB7 is cut flush to
the PCB (or else the jack won’t sit flush to the PCB which again
means the jack wouldn’t sit in its place properly). The barrel jack
pins are smaller than the hole diameters on the PCB, so make
sure the jack is soldered such that it matches the component
outline. Solder one of the pins of the jack on the bottom side.
Turn the PCB upside down and solder PB7 and the
remaining P1 jack pins on the top side of the PCB. Also solder
PD1 and PD2 from the top side of the PCB.
Now, the four common layer anode leads (the uncut staircase type
leads; see Figure 36 again) need to be joined to their corresponding
pads (L0, L1, L2, L3) on the PCB. Use straightened tin wire pieces to
make the connections. The common anode to bottom Layer 0 is
connected to pad L0. The common anode on Layer 1 is connected to
pad L1. The common anode to Layer 2 is connected to pad L2. Finally,
the top (Layer 3) common anode lead should be connected to pad L3.
Next, trim the extended anode leads to the solder joints as shown in
A close-up of the anode
connection wires going into the
PCB pads is shown in Figure 40.
Figure 36. LED matrix on the PCB; note the extended
anodes above the L0 to L3 PCB pads.
the LED matrix
the PCB pads.
Figure 38. Soldering the LED matrix on the bottom
side of the PCB.
the L0, L1,
L2, and L3
Figure 39. Connecting the common
anodes to the PCB using tinned wire.
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