Soldering and assembling
Following tools are necessary to assemble the USB Morse keyer PCB:
- Soldering iron with tiny tip (or SMD rework station)
- Solder
- Solder flux
- A couple of tweezers
- Bench magnifying glass or microscope
- Nipper or cutting tool
During soldering try to solder small SMD components first. During the prototype construction, I solder all SMD capacitors and resistors in the first round. After that, solder U2 (LM324), U5 (TDA7052A), U3 (CH340G), and U4 (L78M05) ICs in order. In next step solder all the transistors.
While assembling through-hole components make sure to follow the following order to avoid any hassles.
- Solder all the ferrite beads.
- Solder SK1 - 28-pin IC socket.
- Solder RV2, SW4, D3, D4, and D5.
- Solder Y1 - crystal. To void short-circuits place some Mylar pad or similar insulator in between the crystal and circuit board.
- Install J5, J7, and J9 headers.
- Install SW1, SW2, SW3, and RV1.
- Solder J1, J3, and J8 sockets.
- Solder all the remaining components into the board except J2, J4, and J6.
- At last solder J2, J4 and J6 sockets.
- Flash PIC16F886 MCU and plug it into SK1 IC socket.
- Connect LCD1 into J5.
Final views of the assembled board should look similar to this:
The top side of the PCB:
The bottom side of the PCB:
