Node Card - Step-By-Step Assembly Guide

[TOC]

Table of contents
  1. Node Card - Step-By-Step Assembly Guide
    1. Before You Begin
      1. Step 1. Review Configuration Options
      2. Step 2. Gather Tools and Materials
        1. Required Materials
        2. SMD Assembly Tools
        3. PTH Assembly Tools
        4. Inspection and Handling
      3. Step 3. Prepare the PCB
    2. SMD Assembly
      1. Step 4: Apply Solder Paste
      2. Step 5: Install Small SMD Components (No Orientation Required)
      3. Step 6: Install Small SMD Components (That Have a Direction)
      4. Step 7: Install Larger SMD Components
    3. PTH Assembly
      1. Step 8: Install Through-Hole Components
    4. Solder PCB
      1. Step 9: Reflow Solder
      2. Step 10: Solder PTH (Plated Through-Hole Components)

Before You Begin

Step 1. Review Configuration Options

Before soldering, determine which options you are building:

  • Power input method(s)
  • CAN bus connection type
  • Node Bus Hub connection (local vs remote)
  • I/O device support
  • Indicators, buzzer, battery backup, SD card, display

Refer to the Assembly Configuration Options in the Node Card documentation.

Step 2. Gather Tools and Materials

Node Card assembly

Required Materials

  • Node Card PCB and stencil
  • PTH and SMD components for your selected configuration
  • PCB standoffs (M3, ~11 mm) and nuts

SMD Assembly Tools

  • Reflow oven (countertop, digital)
  • Solder paste
  • Solder paste applicator (syringe, container, or automatic dispenser)
  • Paste scraper
  • Push pins (for stencil alignment)
  • Sticky pickup tool and/or fine tweezers
  • Isopropyl alcohol and lint-free wipes

PTH Assembly Tools

  • Soldering iron with fine tip
  • Solder (PTH components)

Inspection and Handling

  • Multimeter
  • Magnification (loupe or microscope)
  • Foam board or heat-resistant work surface

Step 3. Prepare the PCB

  1. Inspect the PCB for damage or contamination.
  2. Clean both sides with isopropyl alcohol.

SMD Assembly

Do not install through-hole components, the ESP32 module, or tall connectors at this stage.

Step 4: Apply Solder Paste

Node Card assembly – small SMD components placement

  1. Place the PCB flat on 1/4” foam board to support it during stencil work.

  2. Position the stencil on top of the PCB and align it using the tooling holes (1.0 mm hole along the top edge and along the bottom edge).

  3. Insert push pins through the tooling holes to hold the stencil aligned and in place.

  4. Apply solder paste across the stencil openings, then scrape off the excess so paste remains only in the pads.

  5. Remove the stencil carefully, lifting straight up to avoid smearing paste.

  6. Install the standoffs and nuts now at the four mounting holes using nuts, leaving the board supported and level. This keeps the through-hole leads clear of the surface during reflow

Step 5: Install Small SMD Components (No Orientation Required)

Node Card assembly – small SMD components placement

  1. Place the small surface-mount components that do not have a direction or polarity.

    This includes:

    • All resistors (Rx)
    • Small ceramic capacitors (Cx)
    • Ferrite beads (FBx)

    These parts can be placed in either direction, so orientation is not critical.

Step 6: Install Small SMD Components (That Have a Direction)

Node Card assembly – oriented small SMD components

Install the small surface-mount components that must be placed in a specific direction.

This includes:

  • Diodes (Dx)
  • Zener diodes (ZDx)
  • LEDs (LEDx)
  • Transistors (Qx)
  • PESD1CAN ESD protection diodes (Dx)
  • Small ICs (Ux), such as logic or interface chips

These parts must be oriented correctly:

  • Match the stripe, dot, or notch on the part
  • Align it with the marking on the PCB silkscreen
  • For LEDs, refer to the back of the LED for the cathode markings

Take your time with this step—correct orientation here prevents problems later.

Step 7: Install Larger SMD Components

Node Card assembly – larger SMD components

Install the larger surface-mount components that sit higher on the board and are easier to place once the small parts are done.

This includes:

  • Larger polymer or electrolytic capacitors (Cx)
  • SMD fuse holder (Fx)
  • SMD connectors (Jx), such as USB-C
  • Tactile switches (SWx)
  • SMD voltage regulators (VRx)
  • Buzzer

For polarized parts:

  • Match the polarity marking on the component
  • Align it with the PCB silkscreen

For connectors and switches:

  • Ensure the part sits flat and square on the PCB before reflow

PTH Assembly

Step 8: Install Through-Hole Components

Node Card assembly – PTH components

Install the through-hole components while the board is still flat and before reflow.

This includes:

  • Fuse (Fx)
  • Connectors (Jx), if used
  • Inductor (Lx)
  • Switches (SWx)
  • Female Headers (Jx)
  • Male Pins (JPx)
  • Voltage regulators (VRx)

To keep these parts from moving during reflow:

  • Apply a small amount of solder paste to at least two holes f
  • or each through-hole component
  • Insert the component fully so it sits flush against the PCB
  • The solder paste will hold the part in place during the reflow step

Do not solder the leads yet—final soldering will be done after reflow.

Note: Applying paste to two holes is enough to hold the part during reflow.

Solder PCB

Step 9: Reflow Solder

  1. Place the board with standoffs into the reflow oven (place tin foil on the wire rack to support the 4x standoffs).
  2. Reflow the board until all solder paste has flowed and joints appear smooth and shiny.
  3. Remove the board and allow it to cool naturally. Do not disturb components while the solder is cooling.
  4. Inspect all solder joints under magnification:
    • No solder bridges
    • No tombstoned or shifted parts
    • Clean, even fillets on pads and leads

Step 10: Solder PTH (Plated Through-Hole Components)

Most PTH components were tacked in place during reflow to hold alignment. This step completes the mechanical and electrical soldering.

  1. Verify Alignment
    • Confirm each PTH component is fully seated onto the PCB.○
    • If needed, reheat a single pin and adjust before proceeding.
  2. Complete Soldering
    • Fully solder all pins for each PTH component.
    • Ensure solder flows through the hole and wets both the pad and lead.
  3. Trim and Inspect
    • Trim excess lead length.
    • Inspect for incomplete fill, lifted pads, or accidental bridges.
  4. Clean (Optional)
    • Remove flux residue if needed to improve visibility for upcoming testing.
Last updated on: December 17, 2025 © 2025 Pat Fleming