Assembly

Before starting assembly

Soldering

Zener diodes (D49,50)

Solder D49 and D50.
Diode is a polarized component and therefore take care of direction.
A Black line on diode is cathode. (square pad on pcb) zener diode

Resistors (R1,2,3,4,7,8)

Solder resistors. Don't place on R5 and R6. (They are for i2c)

RefValueColor code
R1,7,81.5kBrown/Green/Red/Gold
R2,375Purple/Green/Black/Gold
R410kBrown/Black/Orange/Gold
R5,6I2CDo not place

resistor

Diodes 1N4148 (D1-48)

Diode is a polarized component and therefore take care of direction. A Black line on diode is cathode. (square pad on pcb) 1N4148

Crystal

crystal

Capacitors (C1,2,4,5)

There are 2 kinds of lead pitch.

RefValueLead pitch
C1,222pF2.5mm
C4,50.1uF5mm

MLCC

USB connector

Narrow pitch! Be careful of solder bridge between pins. USB

LEDs

LED is a polarized component and therefore take care of direction. A short leg is cathode. (square pad on pcb) LED

If you use leds, make bridge J4 and J5 on bottom side. LED jumper

IC socket

Solder IC socket. IC socket is a polarized component and therefore take care of direction. Check the notch on silk and IC Socket.
ic socket

Electrolytic capacitor(C3) and Resettable fuse(F1)

Electrolytic capacitor is a polarized component and therefore take care of direction. A short leg is cathode. (square pad on pcb)

And after soldering resettable fuse, bend like the image. Electrolytic capacitor and resettable fuse

Tactile Switch(SW50,51) and pin header

SW and pin header

ATMEGA328p

Insert ATMEGA328P into IC Socket.

ATMEGA328 is a polarized component and therefore take care of direction. See the image. ATMEGA328p

Check list before connect USB

  • No short between VCC and GND, USB connector pins.
  • Direction of polarized components.(ATMEGA328p, diode, resettable fuse, electrolytic capacitor)
  • Resistor value

NEXT

Connect USB cable and test bootloader