Ramsey Electronics FR220 Instruction Manual - page 19
FR-220
• 19
❒
76. Install R15, 470K ohms (yellow-violet-yellow).
5. FINAL CONNECTIONS: THE LM386 AUDIO IC STAGE
You now have a working FM receiver ready for adjustment. The output of
the MC3359 FM IC simply needs to be boosted to listening level. A few
more connections, and your receiver will be ready for adjustment and
testing! Now would be a good time to review some of your previous work
and also to make sure you have on hand what you'll need for testing:
antenna, fresh battery, earphone or speaker with correct plug or adapter.
❒
77. Review the instructions for installing U1 and U2. Insert the LM386
IC with the band or dot oriented correctly. Solder the 8 connections.
❒
78. Install C32, a 100 to 220 uf electrolytic, observe correct polarity.
❒
79. Install C31, .01 uf (marked .01 or 103 or 10nf).
❒
80. Install C36, 4.7 or 10 uf electrolytic, observe polarity.
❒
81. Install C33, 100 to 220 uf electrolytic, observe polarity.
❒
82. Install the battery snap terminal in the two holes below S1,
making sure that the positive (red) lead is inserted into the (+) hole on
the PC board.
❒
83. The battery bracket may be attached in a variety of ways. A wire
jumper can be passed through the two holes on the PC board, then
both ends soldered on the underside of the board. You may prefer to
use very small screws or even a double-sided mounting adhesive
strip or glue. In using such methods, make sure that the battery will
not block the PC board's mounting hole in its vicinity.
Wiring of the PC board is now complete. If you have the the patience, we
suggest a short break. Then, take a magnifying lens and a bright light
and examine all your solder joints, touching up any connection which
appears less than perfect. Make sure all excess leads have been
trimmed, and that there's not one bent back flat against the board,
probably causing a short. Brush the solder side of the board with a stiff
brush to make sure that no loose wire trimmings or solder drippings (tsk
tsk) are lodged between connections.