Ramsey Electronics FM10A - Manual (Page 10)

Wiring the audio input circuits
We encourage you to peek at the schematic diagram and learn the
functions of the following parts. However, the sequence of installation is in
the order of convenience and speed. If you wish, insert the parts groupings
as one operation, then solder and nip all connections.
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8. Install R1, one of the small yellow trimmer potentiometers marked
"102". Don't confuse it with R7 which is marked "104".
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9. Install R4, the other yellow trimmer marked "102". These two
trimmers will allow you to adjust the input level.
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10. Install C1, .0047 µF (marked .0047 or 472). If you are building your
kit for use in North America or Japan, resistors in steps 11 and 12 are
installed as printed. For use in Europe, Russia and some other
countries, use 10K ohm resistors in steps 11 and 12. These resistors set
the pre-emphasis characteristics for the FM10A. Pre-emphasis is a
technique used in FM transmitters to increase the high frequency signal
to noise ratio. If you desire a "brighter" sound you may use the 10K ohm
resistors rather than the 15K ohm parts.
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11. Install R3, 15K [brown-green-orange].
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12. Install R6, 15K [brown-green-orange].
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13. Install C4, .0047 µF (marked .0047 or 472).
Electrolytic capacitors have a right and wrong way to be installed. Usually,
capacitors have a black strip which indicates their ( - ), negative lead and the
PC board or Parts Layout Diagram will show the ( + ), positive side of the
capacitor's installation hole. Be sure to place the ( + ) capacitor lead into the
PC board ( + ) hole and the ( - ) lead into the ( - ) hole. Observe correct
polarity when installing the following three electrolytic capacitors:
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14. Install C2, 4.7 or 10 µF. Don’t forget... the proper orientation is noted
on the PC board or Parts Layout Diagram.
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15. Install C5, 4.7 or 10 µF. Observe correct polarity.
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16. Install C3, 4.7 or 10 µF. Remember correct polarity.
Diodes also have a right and wrong way to be installed. The cathode
(banded) ends face toward the outside of the PC board, away from the IC
circuitry. Observe correct polarity when installing the following three diodes.