Ramsey Electronics FT146 - Manual (Page 9)

FT146 • 9
❒ 3. Install J2, the subminiature phone jack. Solder all three points. Be
gentle and patient in inserting, so as not to damage the solder tabs.
❒ 4. Install R13, 5K trimmer pot. This is the modulation adjustment control.
❒ 5. Install U1, LM358 op-amp IC chip. In installing the IC, you may wish to
use an 8-pin DIP socket rather than soldering the IC directly to the board.
Reasons for doing this might include the peace of mind of being able to
easily replace the IC if ever necessary. However, please be aware that we
have seen more service problems with improper socket insertion than from
soldering in IC's. Even if this is your first IC, don't be afraid to use enough
heat to make 8 clean connections, but DO be sure to orient the end marked
by a band or dot correctly. Before soldering, make sure that the IC or
socket is perfectly flat against the top of the PC board and that all pins are
properly in each PC board hole. This little 8 pin chip contains two separate
amplifiers and is used to amplify the microphone output and process the
audio for transmisssion.
❒ 6. Install C39, .001 uf disc capacitor (marked .001, 1 nf or 102).
❒ 7. Install C38, .001 uf disc capacitor (marked .001, 1 nf or 102).
❒ 8. Install C36, .01 uf disc capacitor (marked .01 or 10 nf or 103).
❒ 9. Install R14, 100K ohm (brown-black-yellow).
❒ 10. Install R18, 100K ohm (brown-black-yellow).
❒ 11. Install R19, 100K ohm (brown-black-yellow).
❒ 12. Install C41, .001 uf disc capacitor (marked .001, 1 nf or 102).
❒ 13. Install R20, 270 ohm (red-violet-brown).
❒ 14. Install C42, 10 uf electrolytic capacitor. Electrolytic capacitors are
polarized with a (+) and a (-) lead and must be installed in the correct
orientation. Ordinarily, only the negative side is marked on the capacitor
body with a dark band and the (-) sign clearly shown, while PC boards will
usually show the (+) hole location. Use care to ensure proper polarity.
❒ 15. Install JMP2, jumper wire. Use a piece of wire clipped from a previously
installed component bent into a small "U" or wire staple shape. Jumpers act
as electronic "bridges" carrying signals over PC board traces underneath.
❒ 16. Install another wire jumper, JMP1.
❒ 17. Install C34, 10 uf electrolytic capacitor. Remember to observe correct
polarity.
❒ 18. Install C37, .001 uf disc capacitor (marked .001, 1 nf or 102).
❒ 19. Install R17, 47 K ohm (yellow-violet-orange).
❒ 20. Install C40, .001 disc capacitor (marked .001, 1 nf or 102).