Ramsey Electronics FR1 Assembly And Instruction Manual page 9

13. Install R11, 47K ohm (yellow-violet-orange).
14. Install D1, varactor diode. It has a black body with green and red bands.
Observe the correct positioning of the banded end by following the
silkscreen. The green band is positioned as shown on the silkscreen.
15. Install C17, 4.7 or 10 uf electrolytic capacitor. Observe polarity.
16. Install C14, 100 pf disc capacitor (marked 100, 101, or 101K).
17. Install slug tuned coil L1.
Time for a breather... So far we've installed all the parts necessary to tune
our receiver. D1, the varactor diode acts as the variable tuning capacitor
and the other resistors and capacitors are used to properly connect D1 to
the tuning and AFC (Automatic Frequency Control) voltages.
18. Install C19, 100 to 220 uf electrolytic capacitor. Don't forget to observe
proper polarity. C19 is a large value capacitor whose function is to 'smooth'
out any voltage fluctuations which may appear on the power supply
voltage to U3.
19. Install D2, the Zener diode. It has a gray painted glass body with a
black band. Orient the band as shown on the layout diagram. A Zener
diode acts as a voltage regulator, keeping the voltage across it constant.
This keeps frequency drift to a minimum.
20. Install C6, 100 pf disc capacitor (marked 100, 101, or 101K).
21. Install R8, 10K ohm (brown-black-orange).
22. Install R16, 270 ohm (red-violet-brown).
23. Install C11 and C12, both 22 pf disc capacitors (marked 22).
24. Install C20 .01 uf disc capacitor (marked .01 or 103 or 10 nf).
25. Install U3, the SA602 IC mixer-oscillator. The marked end of the IC
(band or dot) must face the EDGE of the PC board. If you wish, install an 8-
pin DIP socket, still remembering to orient and install the SA602 correctly.
PLEASE don't be afraid to solder U3 directly to the PC-board; we have seen
more repair problems with DIP sockets than from direct soldering of ICs.
26. Install C21, .01 uf disc capacitor (marked .01 or 103 or 10 nf).
27. Install R17, 270 ohm (red-violet-brown).
28. Install C4, .001 uf disc capacitor (marked .001 or 102 or 1 nf).
29. Install R5, 10K ohm (brown-black-orange)
30. Install Q2, 2SC2498 or 2SC2570A NPN transistor. Transistors are
VERY critical of correct orientation of their leads. Be sure to pay close
attention to the position of the flat side of the transistor.
FR-1 • 9