Ramsey Electronics FX-440 Manual page 91

STAGE DR ASSEMBLY:
Our assembly sequence will begin at the antenna input and will be
complete when the installation of C78 couples the collector of 017 to pin
20 of the MC3335 FM IC. Primarily for learning purposes, we will install
- only .the components needed for receiving.
Be very att ive to capacitor values (in picofarads) and to coil
descriptio throughout this section.
[ I
r\./',9R1.1nstall C71, 4.7 ors pf.
[ ] [v(
DR2. Install C72, 4. 7 or 5 pf.
[ I
[~DR3.
Winding of L12: . .. .
1
Use the heavier gauge, bare, tinned wire in your
kit
for winding
L 12. Wind this coil on the threads of the 1/4 • x 20 bolt to assure
perfect forming of the coil. (Or, if need be, the job can be done
using any true 3/16" OD object such as a screwdriver shaft, etc.
DO NOT try any other diameter).
This coil will appear to have 2 turns if viewed from the top. The
"legs• or leads on L12 should be 1/4" long and the coil should sit
118" maximum above the PC board. Install L12 as shown:
1/8 in. 1/4 in.
[ ] !u---eR4. Install L24, .015 uh. The .015 uh inductors are the small
red color 2 turn pre-wound coils.
[ ] [\,f'
DRS. Select L23, another .015 uh coil. Bend out each lead from
the coil so it extends straight out. Insert one lead into the L23 hole
on the PC board, allow the coil to sit about 1/4 •·above the board
and solder, the other lead will be soldered to the S0-239 antenna
connector
at
a later step.
_IL
L23
[ ] [ \.f"DR6. Install C63, 27 pf.
\~
L23~7
PC Boord
[ ] [
~DR7.
Correctly identify and install PIN diode D6. It is the only
BA389 used in the circuit, and its number is stamped plainly on
· the diode body. Be sure to orient the cathode end correctly!
.... FX-440 Assm. 31