Ramsey Electronics SCA1 User Manual - page 13
SCA1
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25. Install C1, .01uf disc [marked .01 or 103 or 10nf].
26. Install C11, .001uf disc [marked .001 or 102].
27. Install C3, .001uf [marked .001 or 102].
28. Using a scrap resistor lead, form a jumper wire to insert in the PC
board in the JMP1 position. Jumpers act as electronic bridges carrying
signals over PC board traces underneath.
29. Install R14, 22K ohm [red-red-orange].
The VCO/PLL section of the SCA1 is now complete. The VCO’s internal
oscillator frequency can be adjusted using pot R1. The PLL section will then
compare the applied input frequency with the VCO frequency. If they are within
“locking range” the PLL section will adjust the VCO control voltage to make it
lock to exactly the same frequency as the input. If the input frequency changes
(as when it is frequency modulated), the VCO will track and follow it exactly. In
this way, the control voltage provides an exact replica of the modulation on the
input signal.
AUDIO FILTERING AND AMPLIFICATION
30. Install R10, 1K ohm [brown-black-red].
31. Install C16, 10uf electrolytic capacitor (observe correct polarity).
32. Install R9, 1K ohm [brown-black-red].
33. Install C14, .01 disc [marked .01 or 103 or 10nf].
34. Install C13, .1 uf disc [marked .1 or 104].
35. Install C12, .1 disc [marked .1 or 104].
36. Install R8, 1K ohm [brown-black-red].
37. Install Q2, the 2N3904 transistor. Observe correct placement of the flat
side.
38. Install jumper, JMP2. Use a scrap resistor or component lead..
39. Install R11, 1K ohm [brown-black-red].
40. Install C15, 10 uf electrolytic. Make certain that the polarity is correct.
41. Install C17, 220 uf electrolytic. Check that polarity!