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Take a break and get your soldering skills saved up for the construction of
the display board. Locate the small display board and install the following
parts:
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65. Install U1, a 4511, BCD to 7 segment display driver IC. Do not use a
socket for this part since it must sit below the LED displays. Observe
correct orientation.
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66. Install jumper JMP5.
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67. Install DS2, one of the LED displays. Notice the decimal point faces
the lower right of the board. This is where the soldering becomes difficult.
The pads are very close to the traces, and solder bridges are easier to
make. A small tipped soldering iron with a clean tip (wipe it often on a
damp sponge) is required for best results. This is where patience really
counts!
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68. Install R3, 75 ohm resistor (violet-green-black). This is a current
limiting resistor for DS2.
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69. Install LED display DS1 use the same care that you used for
installing DS2.
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70. Install R2, 75 ohm resistor (violet-green-black). This is another
current limiting resistor.
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71. Install S2, one of the mini push button switches. It should sit neatly
above the board. S2 selects the desired message's address.
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72. Install S1, the mini push button switch for selecting the mode.
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73. Install S3, the last mini push button switch. S3 is the PLAY switch.
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74. If you are planning to use this kit in the stand alone mode (without
hook-up to a radio transceiver), install MK1. This is the small microphone
in the silver can with black top. Look closely at the mike and notice how
the pins are off center. The mike must be installed as shown in the parts
layout diagram.
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75. Install R25, 1K ohm resistor (brown-black-red). This resistor supplies
power to the microphone.
Now is a good time to check out all of your solder joints, on both the main
board and your display board, also check for proper part orientation and
polarity.
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76. Locate POT1, the switched potentiometer. Mount the potentiometer
CB-1 • 13
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