SP-1
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14
84. Install R14, 10K (brown-black-orange).
85. Install R20, 10K (brown-black-orange).
86. If you have not done so already, install U1, MC65118 in its previously
installed socket . Do this with care and make sure that all 28 IC pins make it
into their socket holes. (It's quite easy to get a pin bent back under the IC
body as well as just missing a socket hole.) Also be sure to place the IC so
that the dotted or notched end lines up with the dot or notch on the PC
board silkscreen. If necessary consult the Parts Layout Diagram for correct
placement.
Take a break, clean up the workspace a bit, and then give your work a good
double check, looking especially for the following:
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Correct orientation of parts?
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Any missed solder connections?
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Untrimmed wires bent back on another connection?
INITIAL TEST: SPEAKERPHONE MODE
1. Solder a Jumper Wire from point "A" to point "C" (near D3).
2. Set both S1 and S2 to their "out" or off position. Set the volume control to a
mid-range point.
3. Next, test the modular phone cord you intend to use with the SP1, even if it is
brand new. Do this simply by trying it on another telephone. Then, connect the
cord between the SP1's J2 and a working, correctly-wired phone jack.
(Defective modular plugs, cords or jacks are a major cause of telephone
malfunction.)
4. Connect a speaker in accordance with Assembly Step 5. For decent audio
quality, use a speaker at least 3" in diameter. A properly-enclosed speaker will
sound better and louder than a speaker lying naked on a workbench.
5. Press S1 to the "in" (on) position. You should hear a normal dial tone. Adjust
volume control as desired. If you do not get a dial tone, recheck all your work,
starting with the phone line and speaker wires.
6. With S-1 still on, tap the microphone, and you should hear the sound in the
speaker.
7. Speak in a normal tone of voice near the microphone, and the dial tone
