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ARRL ETP Solder 101 24-Hour Clock Kit Construction Manual
Parts Inventory
Cross-check the parts against this parts list. Note the resistor color codes,
especially the 10K (brn-blk-org) and 1K (brn-blk-red) resistors, which may
be difficult to tell apart. (Use good lighting and a magnifier.) Use care to
correctly identify the 78L05 voltage regulator, which is similar in
appearance to the 2N3906 transistors. The 0.1µF and 10pF capacitors may
also look very similar.
QTY
Description
❒ 1 printed circuit board
❒ 1 PIC16C54 microcontroller
❒ 1 18-pin DIP socket
❒ 1 78L05 voltage regulator
❒ 4 2N3906 PNP transistor
❒ 4 7-segment LED
❒ 1 1N914 diode
❒ 1 4 MHz crystal
❒ 4 10pF capacitor (100)
❒ 2 0.1µF capacitor (104)
❒ 8 220 ohm 1/4 W resistor (red-red-brn)
❒ 3 750 ohm 1/4 W resistor (vio-grn-brn)
❒ 4 1K ohm 1/4 W resistor (brn-blk-red)
❒ 4 10K ohm 1/4 W resistor (brn-blk-org)
❒ 3 SPST pushbutton switch
❒ 1 3-AA cell battery holder
❒ 1 vertical power jack, 2.1x5.5 mm
❒ 1 2-56 1/2-inch screw
❒ 1 2-56 nut
A Functional Approach
[B]
[C]
[D]
[E]
[A]
[F]
[G]
A
B
C
D
E
G
F
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Summary of Contents for ARRL ETP Solder 101
- Page 1 ARRL ETP Solder 101 24-Hour Clock Kit Construction Manual A Functional Approach Parts Inventory Cross-check the parts against this parts list. Note the resistor color codes, especially the 10K (brn-blk-org) and 1K (brn-blk-red) resistors, which may be difficult to tell apart. (Use good lighting and a magnifier.) Use care to correctly identify the 78L05 voltage regulator, which is similar in appearance to the 2N3906 transistors.
- Page 2 Safety • Apply power to the board only when instructed. • Double-check part identification and polarity (if any) before soldering. • Wear eye protection when soldering and trimming component leads. Use care when clipping off the excess leads because they can flip up and cause eye injury.
- Page 3 Power Circuit Locate the 1N914 diode. Note the banded end of the diode (the cathode). Install the diode at the appropriate location, taking care to install it with the banded end turned to match the band of the component outline. Mount the diode flush with the surface of the board.
- Page 4 PIC Socket Installation Locate the 18-pin IC socket. One end of the socket is marked with a notch. The socket outline on the circuit board also has a notch. When you install the socket, turn the socket so that the notches match up. Notch Hold the socket in place flush against the board and solder two opposite corner pins.
- Page 5 Current Limiting Resistor Installation Install eight 220-ohm resistors (red-red-brn) at the indicated locations, flush against the circuit board. Solder and clip the excess leads. 220-ohm resistors Install four 1K-ohm resistors (brn-blk-red) at the indicated locations, flush against the circuit board. Solder and clip the excess leads. 1K-ohm resistors...
- Page 6 Install three 750-ohm resistors (vio-grn-brn) at the indicated locations, flush against the circuit board. Solder and clip the excess leads. Install three 10K-ohm resistors (brn-blk-org) at the indicated locations, flush against the circuit board. Solder and clip the excess leads. You should have no resistors remaining.
- Page 7 Display 7-Segment LED installation Locate the four 7-segment LEDs that make up the time display. The pins on the back of these LEDs are not arranged symmetrically — this helps you install the LEDs correctly. If you try to force the LEDs in the wrong direction, you can bend the pins and damage the LEDs.
- Page 8 Oscillator installation Install the 4MHz crystal in the indicated position. The orientation of the crystal is not critical. Solder the crystal flush with the board and clip off excess leads. Install the four 10pF capacitors in the indicated locations. Solder and clip Crystal oscillator and loading capacitors off excess leads.
- Page 9 Microcontroller Installation You will now install the PIC 16C54 microcontroller. To align the pins of the PIC with the holes in the socket, turn the PIC over and gently bend the pins on each side inward until they are at a 90° angle with the bottom of the PIC.
- Page 10 Power Connector Installation Locate the power connector. The power connector is installed from the bottom, or solder side of the board. Install the connector and hold it in place against the work surface while you tack solder a single pin. Check that the connector is flush against the circuit board surface.
- Page 11 Back-Up Battery Holder installation Carefully bend the two leads on the back of the battery holder out at a 90° angle, and install the battery holder from the solder (bottom) side of the circuit board. Before you solder the battery holder leads, use the 2-56 screw and nut to fasten the battery holder to the back of the PCB.
- Page 12 Tests and operation It’s now time to fire-up your completed project. Install the wall wart barrel plug into the power connector on the back of the clock, then plug the wall wart into an outlet. The digits of your clock should illuminate and the center colon dots should blink at 1-second intervals.
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