■ PHOTO 5.
are eight of these transistors. A transistor goes where you
see a cluster of B, E, and C letters.
5. The 555 (U1) is mounted next. Make sure pin 1 is
6. Now mount the capacitors starting with C1, a 0.01
µF ceramic disc. C1 is located at the far left near the
middle of the board. C2, C3, and C4 are 4. 7 µf tantalum
polarized capacitors. Look for the + sign on Figure 4 at
C2, C3, and C4. C5 is a 0.001 µF ceramic located next to
the 555 chip, U1. C6 (a 0.1 µF ceramic) is located above
the two diodes. C7 (also 0.1 µF) is located near U1
7. The 10 LEDs are mounted using a spacer. Look at
Photo 5. The wood spacer is seven inches long, 0.35 inches high, 0.1 inches thick at the base, and tapered to 0.05
thickness at the top. It’s shaped like a trapezoid. Be sure
that the flat side of the base of the LED is positioned as
shown in Figure 4. Put the wood spacer in place and
solder only one lead of each LED. This will allow you to
pull out the wood spacer. Sight down the LED row and
adjust any that are out of line. Now solder the other lead.
The POWER LED is located at the lower left corner next
to R21. The flat side is facing in towards the center of the
board. Use the wood spacer and solder only one lead.
Remove the spacer and solder the second lead.
8. Install the jumper wire next to the 555 chip as shown
on Figure 4.
9. Figure 5 is an x-ray view of the foil as seen from the
parts side. My CAD software (free from ExpressPCB) will
not allow me to flip the board over. Start at the bottom
left side of the board and note a nine inch (preferably a
#20 stranded black) wire connected underneath it going
to the cell holder negative terminal. Do not solder to the
cell holder at this time. Using a different color wire, (red,
for example), connect a nine inch #20 stranded wire to a
toggle switch. Now connect a three inch wire from the
switch to the board as shown. This becomes the POWER
switch. Twist the two nine inch wires together for about
five inches starting at the cell holder end.
10. The BUZZER switch is next. Solder a three inch
wire to the board and switch. The BUZZER has its own
red and black wire, and will be addressed when it is
fastened to the front panel.
11. The RESET switch (far right) is a push button switch,
the same used at the hand switches. Connect two 2.5
inch wires to the switch and to the board as indicated in
Figure 5 — the left wire on the top of the board and the
right wire underneath the board. Just sweat the wire to the
foil. Set the PCB board aside for now.
Front Panel Construction
Patterns for construction of the actual quiz box (listed
as Figures 6 and 7) are available on the Nuts & Volts
website at www.nutsvolts.com along with all the other necessary files to complete this project. The front panel board is
10 x 5.2 x 0.1 inches and is made of Masonite material. I
spray paint the board and then silkscreen the letters/
numbers on. Using a punch works better than drilling.
Construct the front panel as follows:
1. Mount the BUZZER to the front panel by pushing
the two wires from the buzzer through the middle 7/64”
hole. Use two #2-56 x 1/2” screws through the buzzer
mounting holes and then down through the remaining
7/64” holes. Using #2 tooth washers and nuts, secure the
buzzer to the front panel.
2. Solder the black BUZZER wire to the top of the
PCB as shown in Figure 5. Solder the red buzzer wire
■ FIGURE 5.