Ramsey Electronics FM25A Assembly And Instruction Manual - page 11
FM25A
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1. Install S1, the DPDT horizontal push-button switch. It fits correctly only
one way. Ensure that the white plastic switch extends out over the edge of
the printed circuit board. Solder all six pins.
2. Install S2, the small black mini push-button switch. Solder all 4 or 2 pins
depending on the switch provided. This switch snaps into place and sits
flush with the top of the board.
3. Install J2, the Right Channel input jack. Solder all 4 points of the jack se-
curely.
4. Install J3, the Left Channel input jack. Solder all 4 points of the jack.
5. Install J4, the RF output (antenna) jack. Solder all 4 points of the jack se-
curely.
6. Install J1, the 2.5 mm phone jack (external DC input). Solder all 3 pins.
7. Install the 16-pin DIP socket supplied with your kit. There is no right or
wrong direction to this socket, but the U2 IC itself certainly needs to be in-
serted correctly (later). Taking care of this socket early in the project will
help you with positioning additional parts and will fine-tune your soldering
technique. Before soldering, make sure the socket body is flush against the
PC board, and that all 16 pins have been inserted. Bend the two corner
pins to hold it in place while you are soldering. After soldering make sure
that it is flat on the board. Solder all 16 pins and then CAREFULLY check to
ensure you have not caused any "solder bridges" between pins.
8. Now that the IC socket has your prime attention, carefully insert the mi-
crocontroller IC, U2 (marked with a white sticker) into the socket, taking
gentle care that ALL 16 pins get into their proper holes. The orientation of
the notched end, as shown on the Parts Layout Diagram is critically impor-
tant.
9. Install U1 (marked 145170). This IC does not have a socket. Don’t be
afraid of heating it too much. Bend the two corner pins as you did with the
socket for U2. Be sure that all of the pins are through the board and not
bent over on top. Place the notched end as shown on the PC board.
10. Install the 18-pin DIP socket as you did the 16-pin socket in step 7. Be
sure that all 18 pins are through the board before soldering. Install U3
(marked BA1404) in the same manner that you did U2. Watch the place-
ment of the notched end.
Progress Note: The preceding steps have secured a sufficient number of com-
ponents to your PC board to make general orientation around the board much
clearer for installing additional parts. Further parts will be installed in six phases
or groupings.