Ramsey Electronics FT146 - Manual (Page 17)

FT146 • 17
❒ 97. Install D4, 1N4148 style signal diode (glass body with black band).
Observe correct orientation of the banded end.
❒ 98. Install TP3, the last test point. Select a 1K resistor, R29 (brown-black-
red). Trim back one lead wire to a length of inch. Bend this wire into a small
loop as before. Insert the resistor into the PC board and hold it carefully
while you solder it to the board.
❒ 99. Install R22, 1K ohm (brown-black-red).
❒ 100. Install C15, 39 pf disc capacitor (marked 39 or 39K).
❒ 101. Install L4, 2 turn coil wound previously. Be sure it sits flush against the
PC board.
❒ 102. Install C14, 56 pf disc capacitor (marked 56 or 56K).
❒ 103. Install L3, another 2 turn coil. Be sure it sits flush against the PC board.
❒ 104. Install C13, 39 pf disc capacitor (marked 39 or 39K).
❒ 105. Install C7, .001 uf disc capacitor (marked .001 or 1000 or 102).
❒ 106. Install C12, trimmer capacitor (black body with orange top).
❒ 107. Install L2, 1 turn coil wound previously. Ensure it sits flush.
❒ 108. Install L1, 6 hole ferrite bead RF choke you wound.
❒ 109. Install C1, .01 uf disc capacitor (marked .01 or 103 or 10 nf).
❒ 110. Locate Q6, SD1127 RF power transistor. This transistor mounts
somewhat differently from all the other parts. Turn over the PC board and
set the transistor snugly into the large hole and bend the leads over and into
the indicated holes. The leads should be as short as possible without
shorting against the transistor case. Solder the three transistor leads. See
drawing in the step below.
❒ 111. Now we call for something unusual - soldering the transistor case to the
PC board. Run a neat "flow" of solder around the transistor case to the PC
board ground plane. The SD1127
power transistor is designed by
the manufacturer to be soldered
directly to a PC board ground
plane for heat sinking and proper
VHF performance. This part is different from other metal can transistors in
that the case is connected internally to the emitter rather than the collector.
This provides much higher gain at VHF frequencies.
Component side of
b d
Solder side of
board
Solder can to PC
board