Connecting 2 or More Quiz Boxes
Figure 3 shows the schematic for when two or more
quiz boxes are connected together (also see Photo 3).
Observe that pin 1 of both D-SUB sockets connects Vcc +
of both quiz boxes and pin 5 connects the grounds. What
happens to the base of Q8, the reset circuit? Pin 4 of line
“E” says that the base of Q8 gets grounded. The reset
switch on all quiz boxes connected on the right side of
the first quiz box no longer function. The left quiz box
becomes the control box.
Now look at line “D”, pin 3, and realize that all of the
SCR cathodes of both boxes are connected. The two quiz
boxes now function as one 20 contestant quiz box. There
is no limit to the number of boxes that can be connected
together. Any four-pin male and female round plug and
socket can be mounted on the side of the wood case
to use however, the D-SUB socket has not been easy
Note: When connecting two or more quiz boxes,
have all power switched OFF on all boxes until the boxes
are properly connected. Turn OFF all BUZZER switches
except the leftmost box to conserve power and
extra noise. When all boxes are connected and
you are ready to quiz, turn ON all the power
switches on all the boxes.
■ PHOTO 3.
2. Place resistors R11-R20 and R- 38, 1K ohm. Using the
Parts List, put the remainder of the resistors and two
diodes on the board. The cathode of both diodes (D12,
D13) is to the right as the symbol indicates.
3. The SCRs should now be installed. The pin-out is
shown in the upper righthand corner of Figure 4. A top
view of the SCR is shown defining the (A) anode, (G) gate,
and (K) cathode.
4. The 2N3904 transistors are next with the pin-out
shown at the lower righthand corner of Figure 4. There
Circuit Board Construction
Figure 4 and Photo 4 show the layout and
placement of parts on the PCB (printed circuit
board). A suggested PCB construction goes
1. Insert and solder resistors R1-R10, 3.3K ohm,
at the top of board. The last 3.3K ohm resistor is
R36 located at the lower righthand corner.
■ PHOTO 4.
■ FIGURE 4.
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