Assembling the PCB

The first picture on the left shows the components for the power supply installed. The 5 volt regulator, 33V zener diode and large 2200uF capacitor. Note the capacitors orientation when installed. Connect a 9 volt battery across the zener and make sure that the CPU voltage is getting regulator to 5v. If not and correct before continuing.

The center picture shows the the various resistors for the remote input step signals, keypad, LCD pull-ups and LCD contrast pot that need to be installed as well as the 20Mhz ceramic resonator. 

The right picture shows the PIC18F6722 installed. This will be the most delicate and important soldering process of the entire project! I needed to use my inspection scope and a fine soldering tip and a great deal of patience in order to get it properly positioned to solder all 64 pins without shorting to one another. Patience here pays large dividends in troubleshooting later. Use an ohm meter and fine wires as probes to make sure each pin is not shorted to its neighbor. Hopefully, an Exacto knife between the pads in question will address this. Finally, make sure that you check continuity between the top of each pin and its corresponding connection pad by touching the pin very lightly so as to not press to hard on the pin and give you a false indication of a good connection. I had a few cold solder joints that I caught by doing this. Again, this will help avoid intermittent issues later.

The ceramic resonators lettering seems to want to be installed facing the 2200uF cap or the CPU does not startup and run.

The MCLR/Vpp 10K resistor and 1N4148 diode circuit has been installed just below the CPU pad. Position the diodes band closest to the CPU pads.

A small decoupler cap has been installed just to the left of the CPU pad. 

A 10K pull-up to support in-circuit programming has been installed just below and to the left of the 20Mhz ceramic resonator.

The step and direction signals are all 10K. With regard to the 2 sets of 4 resistors around the 2200uF cap, the 2 outer most resistors are 1K value and the 2 inner most resistors are 10K values. All of the step and direction pull-ups are 10K.

The above picture on the left shows my Pickit-3 installed and in the process of programming a board. The complete programming process has been described in the "Programming the PIC18F6722" section of this website and should be done at this point.

The center picture shows the LCD and keypad ribbon cables that will eventually need to be installed soldered. For now, just solder the LCD ribbon cable to the LCD. But do not solder the ribbon cable to the PCB at this time!

Notice that I skipped the last two holes (#15 & #16) with the ribbon cable as they are not needed .... assuming the correct LCD was ordered.

The picture on the left shows me just sticking the ribbon cable into the PCB and just holding  it to make good enough contact to see of the CPU would boot-up once a 9 volt battery was connected. If you do not see the CPU boot at this point then something somewhere is not right and needs to be found and corrected before continuing on.

The center picture shows the 1K pull-up resistors and 2 amp flyback diodes installed into the PCB. Make sure that the diode bands are positioned towards the center of the board. The circuit design says 1 amp diodes but I installed heavier 2 amp ones for the larger motors that I am using. I never got around to updating the schematic yet .... someday.

The picture on the right shows the 4 amp Darlington transistors installed and soldered in. Make sure that the alignment of the transistors is consistent as that will make bending them (below picture) and installing them on the heat-sink easier later.

NOTE: I actually pre-bend the transistors now using a jig or nice pair of needle nose pliers. I do this so as not to stress the plastic case or break a leg of the transistor. This way seems easier to me in order to get almost identical bends on the legs of the transistor. The spacing consistency between the transistors will make the process of positioning the completed PCB assembly on the heat-sink and installing the associated mounting screws much easier later.

Above is (hopefully) what the completed PC board looks like.